Shuhui Bo - Cochemist

Synthesis of chromophores with ultrahigh electro-optic activity: Rational combination of the bridge, donor and acceptor groups

Co-reporter:Fenggang Liu, Hongyan Xiao, Huajun Xu, Shuhui Bo, Chaolei Hu, Yanling He, Jialei Liu, Zhen Zhen, Xinhou Liu, Ling Qiu

Dyes and Pigments 2017 Volume 136() pp:182-190

Publication Date(Web):January 2017

DOI:10.1016/j.dyepig.2016.08.048

•A series of high performance chromophores had been synthesized and studied.•The glass transition temperature of the three chromophores is higher 110 °C.•The films containing the three chromophores showed ultrahigh electro-optic activity.A series of high performance chromophores P1P3, based on N-(4-dibutylaminophenyl) tetrahydroquinolinyl or julolidinyl donors, and phenyl-trifluoromethyl-tricyanofuran acceptors linked together via π-conjugation through thiophene or vinylene moieties as the bridges, have been designed and synthesized. Density functional theory (DFT) was used to calculate the HOMO-LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Chromophores P1 and P3 had good thermal stabilities with glass transition temperature higher than 110 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers with rational chromophore designs. In electro-optic activities, the poled films of P1/APC, P2/APC and P3/APC afforded r33 values of 223, 283 and 278 pmV−1, respectively, at 1310 nm at the doping concentration of 25 wt%, which showed significant enhancement over the similar EO polymer systems previously reported.

Enhanced electro-optic activity from the triarylaminophenyl-based chromophores by introducing different steric hindrance groups

Co-reporter:Lu Chen, Yanling He, Fenggang Liu, Jialei Liu, Hua Zhang, Fuyang Huo, Shuhui Bo, Hongyan Xiao, Zhen Zhen

Materials Letters 2017 Volume 196(Volume 196) pp:

Publication Date(Web):1 June 2017

DOI:10.1016/j.matlet.2017.03.052

•Site-isolated chromophores L1 and L2 were synthesized with easy five steps and high yield.•Both chromophores L1 and L2 have good thermal stability and solubility in organic solvents.•The r33 values of film-L1/APC and film-L2/APC are respectively 2.3 times and 3 times of that of film-T1/APC.Chromophores L1 and L2 based on modified triphenylamine donors with diverse steric hindrance groups, have been designed in order to achieve large macroscopic r33 value of NLO polymers comparing to traditional triarylaminophenyl chromophore T1. In electro-optic activities, the doped film L1-APC and L2-APC showed r33 value of 37 pm/V and 49 pm/V at the concentration of 25 wt%, which were more than two times higher than that of film T1/APC (16 pm/V). These properties, together with the good thermostability, suggest the potential use of the new chromophores as advanced material devices.Download high-res image (50KB)Download full-size image

Enhanced electro-optic activity of two novel bichromophores which are synthesized by Cu(I) catalyzed click-reaction

Co-reporter:Yanling He, Lu Chen, Fenggang Liu, Hua Zhang, Fuyang Huo, Zhuo Chen, Jialei Liu, Zhen Zhen, Xinhou Liu, Shuhui Bo

Dyes and Pigments 2017 Volume 139(Volume 139) pp:

Publication Date(Web):1 April 2017

DOI:10.1016/j.dyepig.2017.01.009

•Two novel bichromophores YL1 and YL2 were synthesized by Cu(I) catalyzed click-reaction.•The Td values of the new bichromophores are both higher than 250 °C.•The r33 values of film-YL1/PMMA and film-YL2/PMMA are higher than that of film-YL/PMMA.Two novel bichromophores YL1 and YL2 based on traditional aniline chromophore YL were synthesized by Cu(I) catalyzed click-reaction and systematically investigated in this paper. The UV–Vis, electrochemical property, thermal stability and EO activity of these chromophores were systematically studied and discussed. These two bichromophores showed good thermal stability. Then nonlinear optical polymer films were fabricated by doping chromophores into polymethylmethacrylate (PMMA). The doped films containing bichromophores YL1 and YL2 showed r33 values of 20 and 17 p.m./V at concentration of 25 wt% at 1310 nm. These values were respectively 2.85 times and 2.43 times of the EO activity of chromophore YL (7 p.m./V). High r33 values indicated that the new structure of bichromophores YL1 and YL2 can reduce intermolecular electrostatic interactions, thus enhancing macroscopic EO activity. These properties suggested the potential use of the new bichromophores in nonlinear optical materials.Download high-res image (181KB)Download full-size image

Synthesis of novel nonlinear optical chromophores: achieving enhanced electro-optic activity and thermal stability by introducing rigid steric hindrance groups into the julolidine donor

Co-reporter:Hua Zhang;Hongyan Xiao;Fenggang Liu;Fuyang Huo;Yanling He;Zhuo Chen;Xinhou Liu;Ling Qiu;Zhen Zhen

Journal of Materials Chemistry C 2017 vol. 5(Issue 7) pp:1675-1684

Publication Date(Web):2017/02/16

DOI:10.1039/C6TC05414E

A series of chromophores z1–z4 have been synthesized based on julolidine donors modified by four different rigid steric hindrance groups including benzene, 2,3,4,5,6-pentafluorobenzene, 3,5-bis(benzyloxy)benzene and 3,5-bis(2,3,4,5,6-pentafluorobenzoate)benzene, respectively, with the same thiophene bridges and strong tricyanovinyldihydrofuran (TCF) acceptors and with high yields. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Besides, to determine the redox properties of these chromophores, cyclic voltammetry (CV) experiments were performed. All these four chromophores showed superb thermal stabilities with high thermal decomposition temperatures above 265 °C. Most importantly, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate their relatively β values into bulk high EO activities. By doping chromophores z1–z4 with a high loading of 25 wt% in APC, EO coefficients (r33) of up to 99, 104, 97 and 89 pm V−1 at 1310 nm can be achieved, respectively. The normalized r33 value was increased to 6.84 × 10−18 pm cc per (V molecules) for z4 possessing the largest steric hindrance group which indicates the weakest dipole–dipole interaction and highest polarization efficiency. The high r33 value, good thermal stability and high yield suggest the potential use of the new chromophores in nonlinear optical areas.

Enhancement of electro-optic properties of bis(N,N-diethyl)aniline based second order nonlinear chromophores by introducing a stronger electron acceptor and modifying the π-bridge

Co-reporter:Hua Zhang;Yuhui Yang;Hongyan Xiao;Fenggang Liu;Fuyang Huo;Lu Chen;Zhuo Chen;Ling Qiu;Zhen Zhen

Journal of Materials Chemistry C 2017 vol. 5(Issue 27) pp:6704-6712

Publication Date(Web):2017/07/13

DOI:10.1039/C7TC01175J

A series of highly polarizable chromophores y1, y2, yz1 and yz2 based on the same bis(N,N-diethyl)aniline donor, a tricyanofuran acceptor (TCF) and a CF3-Ph-TCF acceptor linked together via thiophene and modified thiophene π-conjugation have been synthesized and are systematically investigated in this paper. Density functional theory (DFT) calculations suggested that the molecular quadratic hyperpolarizability (β) value of the CF3-Ph-TCF based chromophore is 16.8% (yz1 compared with y1) and 46.8% (yz2 compared with y2) larger than those TCF based chromophores. These chromophores showed good thermal stability and their decomposition temperatures were all above 230 °C. Compared with the results obtained from the chromophores (y1 and y2) with the TCF acceptor, the new chromophores (yz1 and yz2) with the CF3-Ph-TCF acceptor show better intramolecular charge-transfer (ICT) absorption (108 nm and 97 nm red-shift). By doping chromophores y1, y2, yz1 and yz2 with a high loading of 25 wt% in amorphous polycarbonate (APC), electro-optic (EO) coefficients (r33) of up to 149, 139, 142 and 252 pm V−1 at 1310 nm can be achieved, respectively. A normalized r33 value of 15.57 × 10−18 pm cc per (V molecules) and an order parameter of (Φ) up to 27.3% was obtained for yz2 possessing the bis(N,N-diethyl)aniline donor, the alkoxy chain modified thiophene bridge and the CF3-Ph-TCF acceptor, which indicated that the structure–property relationship was essential. The high r33 value, good thermal stability and high yields suggest the potential use of new chromophores in a nonlinear optical area.

Synthesis and characterization of a novel indoline based nonlinear optical chromophore with excellent electro-optic activity and high thermal stability by modifying the π-conjugated bridges

Co-reporter:Chaolei Hu;Zhuo Chen;Hongyan Xiao;Zhen Zhen;Xinhou Liu

Journal of Materials Chemistry C 2017 vol. 5(Issue 21) pp:5111-5118

Publication Date(Web):2017/06/01

DOI:10.1039/C7TC00735C

Two novel second order nonlinear optical (NLO) chromophores based on indoline donors and tricyanofuran (TCF) acceptors linked together via modified polyene π-conjugation bridges have been synthesized in good overall yields and systematically characterized. Thermal stability, optical property and electro-optic property were measured to investigate the effects of the introduced rigid benzene derivative steric hindrance group on the bridge. Besides, density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. After introducing the benzene derivative steric hindrance group into the bridge, chromophore CLH-2 showed very good thermal stability with a decomposition temperature of 250 °C, which was 83 °C higher than chromophore CLH-1 without the isolation group on the bridge. In electro-optic activity, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate the relatively small β values into bulk high EO activities. By doping chromophores CLH-1 and CLH-2 with a high loading of 45 wt% in APC, EO coefficients (r33) of up to 63 and 102 pm V−1 at 1310 nm can be achieved, respectively. The r33 value of the new chromophore CLH-2 was about 1.6 times that of chromophore CLH-1. The high r33 value, good thermal stability and high yield suggest the promising applications of the new chromophore in nonlinear optical areas.

Synthesis of julolidine-containing nonlinear optical chromophores: Achieving excellent electro-optic activity by optimizing the bridges and acceptors

Co-reporter:Fenggang Liu, Huajun Xu, Hua Zhang, Lu Chen, Jialei Liu, Shuhui Bo, Zhen Zhen, Xinhou Liu, Ling Qiu

Dyes and Pigments 2016 Volume 134() pp:358-367

Publication Date(Web):November 2016

DOI:10.1016/j.dyepig.2016.07.038

•Two series of high performance chromophores A1-C2 had been synthesized and studied.•The decomposition temperature (Td) of the six chromophores is higher than 200 °C.•The films containing the chromophores showed ultrahigh electro-optic activity.Two series of highly efficient nonlinear optical chromophores A1-C1 and A2-C2 based on the julolidinyl donors and tricyanofuran or phenyl-trifluoromethyl-tricyanofuran acceptors (CF3-Ph-TCF) linked together via π-conjugation through thiophene or pyrrole or tetraene moieties as the bridges, have been synthesized and investigated. The ultraviolet absorption, solvatochromic, thermal stabilities and electro-optic activities of these chromophores were systematically studied to illustrate structure-performance relationships within the six chromophores. All the chromophores exhibited good thermal stabilities with the decomposition temperatures (Td) higher than 200 °C. Appropriate combination of the π-conjugated bridge, electron-donor and electron-acceptor as well as the isolated group in the chromophores plays an important role in achieving larger electro-optic activities. Exemplified by the chromophore A2 with CF3-Ph-TCF acceptor, it gave a very large r33 value of 223 pmV−1 at 1310 nm at the doping concentration of 25 wt%.

Synthesis of novel nonlinear optical chromophores: achieving excellent electro-optic activity by introducing benzene derivative isolation groups into the bridge

Co-reporter:Chaolei Hu, Fenggang Liu, Hua Zhang, Fuyang Huo, Yuhui Yang, Haoran Wang, Hongyan Xiao, Zhuo Chen, Jialei Liu, Ling Qiu, Zhen Zhen, Xinhou Liu and Shuhui Bo

Journal of Materials Chemistry A 2015 vol. 3(Issue 44) pp:11595-11604

Publication Date(Web):12 Oct 2015

DOI:10.1039/C5TC02702K

Three novel second order nonlinear optical (NLO) chromophores based on julolidinyl donors and tricyanofuran (TCF) acceptors linked together via modified polyene π-conjugation with rigid benzene derivative steric hindrance groups (chromophore CL1 and CL2) or unmodified polyene π-conjugation (chromophores CL) moieties as the bridges have been synthesized in good overall yields and systematically characterized. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Besides, to determine the redox properties of these chromophores, cyclic voltammetry (CV) experiments were performed. Compared with CL, after introducing benzene derivative steric hindrance groups into the bridge, chromophores CL1 and CL2 had good thermal stabilities with high thermal decomposition temperatures which were 32 °C and 24 °C higher than chromophore CL, respectively. Most importantly, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate their relatively small β values into bulk high EO activities. By doping chromophores CL, CL1 and CL2 with a high loading of 45 wt% in APC, EO coefficients (r33) of up to 121, 197 and 202 pm V−1 at 1310 nm can be achieved, respectively. The r33 values of new chromophores CL1 and CL2 were about 1.6 times of chromophore CL. The high r33 value, good thermal stability and high yield suggest the potential use of the new chromophores in an nonlinear optical area.

Synthesis and optical nonlinear properties of novel Y-shaped chromophores with excellent electro-optic activity

Co-reporter:Yuhui Yang, Hongyan Xiao, Haoran Wang, Fenggang Liu, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Journal of Materials Chemistry A 2015 vol. 3(Issue 43) pp:11423-11431

Publication Date(Web):24 Sep 2015

DOI:10.1039/C5TC02764K

A series of Y-shaped chromophores A1, A2, B1 and B2 based on the same thiophene π-conjugation and tricyanofuran acceptor (TCF) but with different donors (modified phenothiazine and triphenylamine) have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed excellent thermal stability with their decomposition temperatures all above 270 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-C containing 25 wt% chromophore B1 displayed an r33 value of 72 pm V−1 at 1310 nm, and the doped film-D containing B2 showed a value of 95 pm V−1 at a concentration of 25 wt%. These values are all much higher than the traditional FTC chromophore (39 pm V−1). High r33 values indicated that the special Y structure can reduce intermolecular electrostatic interactions and thus enhance the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of these new chromophores as materials for advanced devices.

Auxiliary donor for tetrahydroquinoline-containing nonlinear optical chromophores: enhanced electro-optical activity and thermal stability

Co-reporter:Fenggang Liu, Maolin Zhang, Hongyan Xiao, Yuhui Yang, Haoran Wang, Jialei Liu, Shuhui Bo, Zhen Zhen, Xinhou Liu and Ling Qiu

Journal of Materials Chemistry A 2015 vol. 3(Issue 36) pp:9283-9291

Publication Date(Web):06 Aug 2015

DOI:10.1039/C5TC01610J

A series of chromophores FTC, L1 and L2 have been synthesized based on three different types of electron donors, including diethylaminophenyl, tetrahydroquinolinyl and N-(4-dimethylaminophenyl) tetrahydroquinolinyl groups respectively, with the same thiophene bridges and strong tricyanovinyldihydrofuran (TCF) acceptors. In particular, the donor part of the chromophore L2 was modified with an additional donor N-(4-dimethylaminophenyl) substituent, resulting in enhanced thermal stability and electro-optic activity. Cyclic voltammetry measurements showed that chromophore L2 had a smaller energy gap than chromophore L1 due to the additional donor. Moreover, density functional theory calculations suggested that the molecular quadratic hyperpolarizability (μβ) value of chromophore L2 is 29% and 44% larger than that of chromophores L1 and FTC, respectively. The doped film containing the chromophore L2 showed an r33 value of 100 pm V−1 at the concentration of 25 wt% which is much higher than the EO activity of the chromophore L1 (57 pm V−1) and two times higher than that of the traditional chromophore FTC (39 pm V−1).

Nonlinear optical chromophores based on Dewar's rules: enhancement of electro-optic activity by introducing heteroatoms into the donor or bridge

Co-reporter:Huajun Xu, Dan Yang, Fenggang Liu, Mingkai Fu, Shuhui Bo, Xinhou Liu and Yuan Cao

Physical Chemistry Chemical Physics 2015 vol. 17(Issue 44) pp:29679-29688

Publication Date(Web):07 Oct 2015

DOI:10.1039/C5CP04959H

In this work, we investigated the enhancement of the electro-optic response by introducing electron-rich heteroatoms as additional donors into the donor or bridge of a conventional second-order nonlinear optical chromophore. A series of chromophores C2–C4 based on the same tricyanofuran acceptor (TCF) but with different heteroatoms in the alkylamino phenyl donor (C2 or C3) or thiophene bridge (C4) have been synthesized and systematically investigated. Density functional theory calculations suggested that chromophores C2–C4 had a smaller energy gap and larger first-order hyperpolarizability (β) than traditional chromophore C1 due to the additional heteroatoms. Single crystal structure analyses and optimized configurations indicate that the rationally introduced heteroatom group would bring larger β and weaker intermolecular interactions which were beneficial for translating molecular β into macro-electro-optic activity in electric field poled films. The electro-optic coefficient of poled films containing 25 wt% of these new chromophores doped in amorphous poly-carbonate afforded values of 83 and 91 pm V−1 at 1310 nm for chromophores C3 and C4, respectively, which are two times higher than that of the traditional chromophore C1 (39 pm V−1). High r33 values indicated that introducing heteroatoms to the donor and bridge of a conventional molecular structure can efficiently improve the electron-donating ability, which improves the β. The long-chain on the donor or bridge part, acting as the isolation group, may reduce inter-molecular electrostatic interactions, thus enhancing the macroscopic EO activity. These results, together with good solubility and compatibility with the polymer, show the new chromophore's potential application in electro-optic devices.

Synthesis and optical nonlinear property of NLO chromophores with alkoxy chains of different lengths using 8-hydroxy-1,1,7,7-tetramethyl-formyljulolidine as donor

Co-reporter:Haoran Wang, Fenggang Liu, Yuhui Yang, Huajun Xu, Chengcheng Peng, Shuhui Bo, Zhen Zhen, Xinhou Liu, Ling Qiu

Dyes and Pigments 2015 Volume 112() pp:42-49

Publication Date(Web):January 2015

DOI:10.1016/j.dyepig.2014.06.024

•Three chromophores had been synthesized and systematically investigated.•The chromophores that had longer alkoxy chains had lower energy between ground state and excited state.•The chromophores that had longer alkoxy chains resulted in relatively larger r33.Three chromophores ZR1, ZR2 and ZR3 based on the electron donor bearing different lengths of alkoxy chains, the same π-electron bridge and tricyanofuran acceptor, have been synthesized and systematically investigated. Density Functional Theory calculations and cyclic voltammetry measurements suggested that ZR2 (with hexyloxy) and ZR3 (with octoxy) had relatively small energy gaps between ground state and excited state than ZR1 (with butoxy) due to the auxiliary electron-donating ability and steric hindrance of their longer alkoxy chains on the donor. The electro-optic coefficient of poled films containing 20% wt of the new dyes doped in amorphous polycarbonate afforded values of 48, 62 and 65 pm/V at 1310 nm for ZR1, ZR2 and ZR3 respectively. These results indicated that the introduction of the longer alkoxy chains on the donor could effectively reduce the intermolecular electrostatic interactions and aid the alignment of the chromophores. This conclusion is conducive to future molecular design.

Novel chromophores with excellent electro-optic activity based on double-donor chromophores by optimizing thiophene bridges

Co-reporter:Yuhui Yang, Shuhui Bo, Haoran Wang, Fenggang Liu, Jialei Liu, Ling Qiu, Zhen Zhen, Xinhou Liu

Dyes and Pigments 2015 Volume 122() pp:139-146

Publication Date(Web):November 2015

DOI:10.1016/j.dyepig.2015.06.012

•New double-donor chromophores were synthesized and systematically investigated.•The influence of different substituted group was systematically discussed.•Chromophore y3 showed smallest energy gap.•The film-C containing chromophore y3 displayed higher r33 value of 157 pm/V.Three novel nonlinear optical chromophores based on the same bis(N,N-diethyl)aniline donor have been synthesized and systematically characterized. These chromophores showed good thermal stability and chromophore y1 showed the best thermal stability of 249 °C. Besides, compared with the chromophore (y1) without the substituted group, chromophores y2 and y3 show better intramolecular charge-transfer absorption. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic coefficients. The electro-optic coefficient of poled films containing 25% wt of chromophores y1–y3 doped in amorphous polycarbonate afforded values of 149, 138 and 157 pm/V at 1310 nm for chromophores y1–y3 respectively. These results indicated that the double donors of bis(N,N-diethyl)aniline unit can efficiently improve the electron-donating ability and the special structure can reduce intermolecular electrostatic interactions, thus enhancing the macroscopic electro-optic activity. These properties, together with good solubility, suggest the potential use of these chromophores as advanced materials.New double-donor chromophores were synthesized and the large hyperpolarizability can be effectively translated into large electro-optic coefficients.

Facile bromine-termination of nonlinear optical chromophore: remarkable optimization in photophysical properties, surface morphology and electro-optic activity

Co-reporter:Jieyun Wu, Shuhui Bo, Wen Wang, Guowei Deng, Zhen Zhen, Xinhou Liu and Kin-seng Chiang

RSC Advances 2015 vol. 5(Issue 123) pp:102108-102114

Publication Date(Web):23 Nov 2015

DOI:10.1039/C5RA20801G

This paper describes how a small molecular structure modification can enhance the microscopic and macroscopic properties of chromophore. A new chromophore WJ10 is synthesized by applying bromine-termination to the remote donor of WJ6, an existing donor–π–acceptor chromophore. This small molecular change can significantly enhance the photophysical properties of chromophore and generate intriguing inverted solvatochromism in solutions. The absorption intensity of chromophore WJ10 in a guest-host electro-optic polymer film is 40–50% higher than that of the chromophore WJ6, which results in the increase of microscopic first-order hyperpolarizability of WJ10 in guest–host electro-optic (EO) polymer film. DFT calculations was carried out to explain this intriguing photophysical property in both solutions and in films. Bromine-termination also has the influence on macroscopic surface morphology of WJ10 in EO films, making WJ10 more homogeneously dispersed than WJ6. In EO activities, EO coefficient obtained with the WJ10 film is more than two times larger (211 pm V−1) than benchmark value 104 pm V−1 obtained from WJ6. The enhanced electro-optic activity with WJ10 is due to the enhancement of the microscopic hyperpolarizability and the better chromophore alignment in the poling process. This study demonstrates the structure–property relationship in bromine-termination of nonlinear optical chromophore, which can be further explored for the synthesis of new organic EO materials.

A study of two thermostable NLO chromophores with different π-electron bridges using fluorene as the donor

Co-reporter:Haoran Wang, Fenggang Liu, Yuhui Yang, Maolin Zhang, Chengcheng Peng, Shuhui Bo, Xinhou Liu, Ling Qiu and Zhen Zhen

New Journal of Chemistry 2015 vol. 39(Issue 2) pp:1038-1044

Publication Date(Web):13 Nov 2014

DOI:10.1039/C4NJ01653J

Two chromophores C1 and C2 based on a fluorene electron donor with different π-electron bridges and the same electron acceptor have been synthesized and systematically characterized using NMR, MS and UV-vis absorption spectra. The energy gap between the ground state and the excited state and molecular nonlinearity were studied using UV-vis absorption spectroscopy, Density Functional Theory calculations and cyclic voltammetry measurements. The different properties between C1 and C2 were systematically compared. The results showed that C2 had a better performance than C1. The electrooptic coefficient of a poled film containing 25 wt% of C2 doped in amorphous polycarbonate afforded a value of 40 pm V−1 at 1310 nm. In addition, the excellent thermostability of C2 made itself a favourable candidate for practical application.

Synthesis and the luminescent properties of the Nd3+ ions doped three kinds of fluoride nanocrystals in organic solvents

Co-reporter:Zhuo Chen, Changyong Tian, Shuhui Bo, Xinhou Liu, Zhen Zhen

Optical Materials 2015 Volume 48() pp:86-91

Publication Date(Web):October 2015

DOI:10.1016/j.optmat.2015.07.025

•Three kinds of Nd ion doped nanocrystals (NCs) were prepared.•There is slight difference of the NCS’ luminescent properties in solid station and liquid station.•The optical loss of the organic solvent indicated that the Nd3+ ions-doped fluoride NCs was examined and studied.Oleic acid (OA)-modified LaF3:Nd, NaYF4:Nd and CaF2:Nd nanocrystals (NCs) with the different Nd3+ ion concentration (2% and 5%) have been prepared. The structure and morphology of NCs were identified by XRD, TEM, FT-IR and TGA. The size of OA-modified NC is a mean diameter of 5–10 nm and can be dispersed in common organic solvents to form a transparent solution. The optical loss of NCs in organic solvent is the first time to discuss in this work. The luminescence properties of NCs were also characterized and studied by fluorescence spectrometer. The nanoparticles in solid and in the solution all exhibited the strong emission at the 1060 nm when the materials were excited around 800 nm. Compared with the LaF3 and CaF2 matrix, NaYF4 as the host can protect the Nd3+ ions more efficiently away from the nonradiative transitions. The longest luminescent lifetime of the solid NaYF4:2%Nd NCs was up to 136 μs, and the little difference of the fluorescence lifetime existed between the NCs in solid state and in solution. The low optical loss in organic solvent indicated that the Nd3+ ions-doped fluoride NCs are promising materials for optical amplification fields.

Nonlinear optical chromophores containing a novel pyrrole-based bridge: optimization of electro-optic activity and thermal stability by modifying the bridge

Co-reporter:Fenggang Liu, Haoran Wang, Yuhui Yang, Huajun Xu, Maolin Zhang, Airui Zhang, Shuhui Bo, Zhen Zhen, Xinhou Liu and Ling Qiu

Journal of Materials Chemistry A 2014 vol. 2(Issue 37) pp:7785-7795

Publication Date(Web):18 Jul 2014

DOI:10.1039/C4TC00900B

Three novel second order nonlinear optical chromophores based on julolidinyl donors and tricyanovinyldihydrofuran (TCF) acceptors linked together via modified pyrrole π-conjugation (chromophores A and B) or thiophene moieties (chromophore C) as the bridges have been synthesized and systematically characterized. In particular, the pyrrole moiety bridge has been modified with the electron withdrawing group (–Br, –NO2) substituted benzene ring. The introduction of side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole–dipole interactions so as to translate their hyperpolarizability (β) values into bulk EO performance more effectively than chromophore C. Moreover, DFT calculations suggested that the additional electron withdrawing groups in chromophores A and B could increase the β value compared to that of chromophore D without substituted phenyl groups, and they showed different influences on the solvatochromic behavior, thermal stability, and electro-optic activity of the chromophores. EO responses (r33 values) of guest–host polymers containing pyrrole-bridged chromophores were reported. Incorporation of chromophores A and B into APC provided large electro-optic coefficients of 86 and 128 pm V−1 at 1310 nm with a high loading of 30 wt%. Film-C/APC containing 25 wt% of chromophore C provides an EO coefficient of 98 pm V−1.

Synthesis and optical nonlinear property of Y-type chromophores based on double-donor structures with excellent electro-optic activity

Co-reporter:Yuhui Yang, Huajun Xu, Fenggang Liu, Haoran Wang, Guowei Deng, Peng Si, Heyan Huang, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Journal of Materials Chemistry A 2014 vol. 2(Issue 26) pp:5124-5132

Publication Date(Web):16 Apr 2014

DOI:10.1039/C4TC00508B

New Y-type chromophores FTC-yh1 and FTC-yh2 containing bis(N,N-diethyl)aniline as a novel electron-donor, thiophene as a π-conjugated bridge and tricyanofuran (TCF) as an acceptor have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed better thermal stability with their decomposition temperatures all above 240 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-A containing 25 wt% chromophore FTC-yh1 displayed a value of 149 pm V−1 at 1310 nm, and the doped film-B containing FTC-yh2 showed a value of 143 pm V−1 at the concentration of 25 wt%. These values are almost four times higher than the EO activity of usually reported traditional single (N,N-diethyl)aniline nonlinear optical (NLO) chromophores FTC. High r33 values indicated that the double donors of the bis(N,N-diethyl)aniline unit can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of the new chromophores as advanced material devices.

Novel second-order nonlinear optical chromophores containing multi-heteroatoms in donor moiety: Design, synthesis, DFT studies and electro-optic activities

Co-reporter:Huajun Xu, Maolin Zhang, Airui Zhang, Guowei Deng, Peng Si, Heyan Huang, Chengcheng Peng, Mingkai Fu, Jialei Liu, Ling Qiu, Zhen Zhen, Shuhui Bo, Xinhou Liu

Dyes and Pigments 2014 Volume 102() pp:142-149

Publication Date(Web):March 2014

DOI:10.1016/j.dyepig.2013.10.042

•A series of novel second-order nonlinear optical chromophores has been synthesized and systematically characterized.•The resulting NLO chromophores exhibited both good thermal stability and good solubility in common organic solvents.•The film-C displayed the highest r33 value of 31 pm/v at the same doping concentrations of 20 wt%.A series of novel second-order nonlinear optical chromophores containing additional heteroatoms in donor moieties has been synthesized and systematically characterized. The resulting nonlinear optical chromophores exhibited both good thermal stability (the decomposition temperature in the range of 249 °C–275 °C) and good solubility in common organic solvents such as chloroform, acetone and N, N-dimethyl formamide. In order to investigate the influence of additional heteroatom on the electro-optic activities, UV–Vis spectra and density functional theory calculations were carried out. The results revealed that the donor derived from m-phenylenediamine had higher electron density compared with other three donors. As to electro-optic activities, the doped polymer film-C displayed the highest electro-optic coefficient value of 31 pm/v at the doping concentration of 20 wt%. All these results indicated that the nonlinear optical activities could be enhanced by introducing suitable additional heteroatoms into donor moiety.

Synthesis and characterization of a novel second-order nonlinear optical chromophore based on a new julolidine donor

Co-reporter:Yuhui Yang, Fenggang Liu, Haoran Wang, Maolin Zhang, Huajun Xu, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Physical Chemistry Chemical Physics 2014 vol. 16(Issue 37) pp:20209-20215

Publication Date(Web):05 Aug 2014

DOI:10.1039/C4CP03185G

A new chromophore HK containing the cis,cis-1,7-diethoxy-3-isopropyljulolidine group as a novel electron-donor, thiophene as a π-conjugated bridge and a tricyanofuran (TCF) acceptor has been synthesized and systematically investigated in this paper. Its corresponding chromophore FTC using 4-(diethyl amino)benzyl as the electron donor group was also prepared for comparison. This is the first time that the cis,cis-1,7-diethoxy-3-isopropyljulolidine group was introduced into NLO materials. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gap and first-order hyperpolarizability (β) of the new chromophore. The HOMO–LUMO gap was also investigated by cyclic voltammetry (CV). Upon using the cis,cis-1,7-diethoxy-3-isopropyljulolidine group as the donor, a reduced energy gap of 1.007 eV was obtained compared with chromophore FTC (ΔE = 1.529 eV). The high molecular hyperpolarizability of the new chromophore can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped films containing the new chromophore HK showed a value of 72 pm V−1 at the concentration of 25 wt% at 1310 nm. This value is almost two times higher than the EO activity of the usually reported traditional (N,N-diethyl) aniline nonlinear optical (NLO) chromophore FTC. High r33 values indicated that the new julolidine donor can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with good solubility, suggest the potential use of the new chromophore in advanced materials devices.

Donor modification of nonlinear optical chromophores: Synthesis, characterization, and fine-tuning of chromophores' mobility and steric hindrance to achieve ultra large electro-optic coefficients in guest–host electro-optic materials

Co-reporter:Jieyun Wu, Chengcheng Peng, Hongyan Xiao, Shuhui Bo, Ling Qiu, Zhen Zhen, Xinhou Liu

Dyes and Pigments 2014 Volume 104() pp:15-23

Publication Date(Web):May 2014

DOI:10.1016/j.dyepig.2013.12.023

•We synthesized three donor-modified nonlinear optical chromophores.•Poling process fine-tuned the steric chromophores' hindrance and free mobility.•Large electro-optic coefficients was achieved in guest–host electro-optic materials.•Steric hindrance improved the temporal stability of electro-optic coefficients.We synthesized three new donor-modified push–pull chromophores with the same divinylenethiophenyl bridge and tricyanofuran acceptor, but with different modified donor moieties. Structure analysis and photophysical properties were carried out to compare the molecular mobility and steric hindrance effect of different donor-modified chromophores. Density functional theory calculations and thermal properties showed the different results of chromophores' microscopic nonlinearity and thermal stability. In electro-optic activities, the poling process demonstrated that guest–host electro-optic polymers containing the chromophores with different steric hindrance and molecular free mobility, required different optimal poling condition to achieve the large macroscopic electro-optic coefficients. After the exploration of the poling condition, it showed an ultra large electro-optic coefficient (266 pm/V) for electro-optic polymer WJ5-APC-2, which indicated the fine-tuning of steric hindrance and molecular free mobility of chromophore WJ5 in host polymer APC-2. Meanwhile, steric hindrance also improved the temporal stability of electro-optic coefficients for WJ5-APC-2.

Comparison of second-order nonlinear optical chromophores with D–π–A, D–A–π–A and D–D–π–A architectures: diverse NLO effects and interesting optical behavior

Co-reporter:Fenggang Liu, Yuhui Yang, Shengyu Cong, Haoran Wang, Maolin Zhang, Shuhui Bo, Jialei Liu, Zhen Zhen, Xinhou Liu and Ling Qiu

RSC Advances 2014 vol. 4(Issue 95) pp:52991-52999

Publication Date(Web):03 Oct 2014

DOI:10.1039/C4RA08951K

Four second-order nonlinear optical chromophores with D–π–A, D–A–π–A and D–D–π–A architectures have been synthesized and systematically characterized. Chromophores A and C have been synthesized with an additional acceptor (–CN) or donor group (thiophene) on the π bridge, termed the D–A–π–A and D–D–π–A configurations. D–π–A structural chromophores B and D were chosen as reference compounds for comparison. The results show that incorporation of the –CN group could increase poling efficiency possibly due to reduced intermolecular dipole–dipole interactions which results in comparable r33 values (48 pm V−1). An r33 value of 45 pm V−1 was obtained for the film C/APC suggesting significant site isolation. Compared with the D–π–A structural chromophores B and D, chromophores A and C demonstrated similar or enhanced NLO effects and better optical transparency.

Synthesis and electro-optic activities of new side-chain polycarbonates containing nonlinear optical chromophores and isolation groups

Co-reporter:Guowei Deng, Heyan Huang, Chengcheng Peng, Airui Zhang, Maolin Zhang, Shuhui Bo, Xinhou Liu, Zhen Zhen and Ling Qiu

RSC Advances 2014 vol. 4(Issue 9) pp:4395-4402

Publication Date(Web):05 Nov 2013

DOI:10.1039/C3RA45514A

Dendritic julolidine-based nonlinear optical (NLO) chromophore (JTCFC) possessing isolation group was designed and synthesized to realize effective isolation of NLO chromophores in the polymer backbone. Electro-optic (EO) polycarbonates (PC-JTCFCs) consisting of the dendritic JTCFC and comonomers were prepared through a facile copolymerization strategy. The sufficiently high polymerizability of the dendritic JTCFC, which could be caused by the well-isolation of chromophores and lack of steric effect, afforded the EO polycarbonates with ultra-high molecular weight (Mw up to 145990). The DSC analysis showed that the EO polycarbonates exhibited similar Tg values (near 150 °C), indicating that the interchromophore interactions are effectively suppressed. The effective isolation of NLO chromophores directly suppressed the dipole–dipole interactions and improved the translation of microscopic hyperpolarizability into macroscopic EO activity. After corona poling, the synthesized EO polycarbonates exhibited a maximum EO coefficient (r33) of 55 pm V−1 at 1310 nm, which was greatly enhanced as compared to the guest–host systems reported previously. Moreover, the prepared EO polycarbonates also possessed good temporal stability, 85% of the initial r33 value of PC-JTCFC-3 could be kept after 500 h at 85 °C.

Novel NLO-phores containing dihexyl amino benzo[b]thiophene exhibiting good transparency and enhanced electro-optical activity

Co-reporter:Maolin Zhang, Huajun Xu, Chengcheng Peng, Heyan Huang, Shuhui Bo, Jialei Liu, Xinhou Liu, Zhen Zhen and Ling Qiu

RSC Advances 2014 vol. 4(Issue 31) pp:15870-15876

Publication Date(Web):21 Mar 2014

DOI:10.1039/C4RA00883A

Two new chromophores (A and B) were synthesized, in which a benzo[b]thiophene moiety was first introduced as a donor group. To investigate the macroscopic EO activity of the new chromophores, guest–host doped polymer films were fabricated by doping chromophores A and B into amorphous polycarbonate (APC). The poled films containing A with a loading density of 20 wt% achieved a maximum EO coefficient (r33) of 42 pm V−1 at 1310 nm, while for the poled films containing B, the r33 value is 75 pm V−1 at 1310 nm. UV-vis spectral absorption of the new chromophores were studied in solutions and films, and chromophores A and B showed a maximum absorption in chloroform of 658 nm and 688 nm, respectively. Compared to the FTC (r33 = 20–50 pm V−1 at 1310 nm, λmax = 685 nm in chloroform) analogues, they exhibited enhanced electro-optical activity together with a high optical gap. This new type of chromophore provided better optimization of the nonlinearity-transparency trade-off.

Comparison of nonlinear optical chromophores containing different conjugated electron-bridges: the relationship between molecular structure-properties and macroscopic electro-optic activities of materials

Co-reporter:Jieyun Wu, Hongyan Xiao, Ling Qiu, Zhen Zhen, Xinhou Liu and Shuhui Bo

RSC Advances 2014 vol. 4(Issue 91) pp:49737-49744

Publication Date(Web):19 Sep 2014

DOI:10.1039/C4RA09368B

In electro-optic (EO) materials, realization of large EO coefficients for organic EO materials requires the simultaneous optimization of chromophore first hyperpolarizability, acentric order, molecular shape etc. As these parameters are complicatedly inter-related, thorough analyses are required to understand the dependence of macroscopic EO activity upon chromophore structure and property. Herein, we presented the synthesis of three chromophores containing different conjugated electron-bridges by acidic and alkaline formylation. Electron-rich moieties thiophene and formyl-thiophene in the different positions of chromophores played the different roles of electron-bridge, site-isolator and electron-isolator, generating intriguing property variations of electron distribution of push–pull structure, intramolecular charge-transfer, solvatochromism, microscopic hyperpolarizability and related density functional theory calculation results. In addition these molecular structure–property relationships were rationally related to the EO activities to understand the impact of microscopic molecular property on macroscopic EO activities of materials.

Synthesis and optical properties of new fluorinated second-order nonlinear optical copolymers: an attempt toward the balance between solubility and long-term alignment stability

Co-reporter:Chengcheng Peng, Jieyun Wu, Jialei Liu, Ling Qiu, Xinhou Liu, Shuhui Bo and Zhen Zhen

Polymer Chemistry 2013 vol. 4(Issue 9) pp:2703-2708

Publication Date(Web):01 Feb 2013

DOI:10.1039/C3PY20935K

A new fluorinated co-polyarylate (P) was synthesized by interfacial polymerization of 1,1-bis(4-hydroxyphenyl)-1-phenyl-2,2,2-trifluoroethane (BPAPF) and diphenolic acid (DPA) with isophthaloyl chloride (IPC). P1–P3, containing different concentrations of tricyanofuran (TCF) accepter chromophores, were obtained by the esterification reaction between P and chromophore 1 catalyst by DCC and DPTS. The obtained co-polyarylates were characterized and evaluated by UV-Vis, 1H NMR, FT-IR, GPC, DSC and TGA. All the co-polyarylates P1–P3 exhibited excellent thermal stability, film forming ability and good electro-optic (EO) activity. The largest r33 value of the copolymers is 52 pm V−1 at the wavelength of 1310 nm, when the concentration of chromophore 1 is 18 wt%.

Synthesis and characterization of novel electro-optic chromophores based on 4-hydroxycarbazole

Co-reporter:Tingting Zhou, Jialei Liu, Guowei Deng, Jieyun Wu, Shuhui Bo, Ling Qiu, Xinhou Liu, Zhen Zhen

Materials Letters 2013 Volume 97() pp:117-120

Publication Date(Web):15 April 2013

DOI:10.1016/j.matlet.2013.01.100

Two novel nonlinear optical (NLO) chromophores with 4-hydroxycarbazole as the electron donor were successfully designed and synthesized. The 4-hydroxycarbazole had two reaction sites where the isolated groups were introduced to the chromophores. The prepared chromophores were characterized by MS, 1H NMR and UV–vis spectra. Poled films of the chromophores doped in APC afforded the maximum electro-optic (EO) coefficient (r33) of 40 pm/V at 1310 nm. This result was better than the similar chromophores reported using carbazole and aniline derivates as electron donor, which indicated that the introduction of isolated groups suppressed the dipole–dipole interaction between chromophores effectively and could aid the alignment of chromophores and improve the EO activity. This had been further demonstrated by the crystal structure analysis.Highlights► Two novel chromophores are successfully designed and synthesized. ► Introduction of isolated groups effectively suppressed the dipole–dipole interaction. ► The maximum r33 value of 40 pm/V at 1310 nm was obtained by corona poling.

Synthesis and electro-optic activities of novel polycarbonates bearing tricyanopyrroline-based nonlinear optical chromophores with excellent thermal stability of dipole alignment

Co-reporter:Guowei Deng, Heyan Huang, Peng Si, Huajun Xu, Jialei Liu, Shuhui Bo, Xinhou Liu, Zhen Zhen, Ling Qiu

Polymer 2013 Volume 54(Issue 23) pp:6349-6356

Publication Date(Web):1 November 2013

DOI:10.1016/j.polymer.2013.09.042

Two series of novel electro-optic (EO) polycarbonates incorporating two kinds of tricyanopyrroline-based nonlinear optical (NLO) chromophores were designed and synthesized. These new polycarbonates were prepared through the facile copolymerization of diol NLO chromophores and bisphenol A bis(chloroformate), and the successful preparations were demonstrated by 1H NMR and Fourier transform infrared (FT-IR) spectra. These polycarbonates possessed good thermal stabilities and also showed higher glass transition temperatures (Tg) in the range of 156–165 °C. After corona poling, the EO coefficients (r33) of two poled polycarbonates films were up to 52 pm/V (PC-DTCPC-Ph-2) and 46 pm/V (PC-DTCPC-FPh-2) at the wavelength of 1310 nm. The higher Tgs endow the polycarbonates' poled films with good temporal stability of poling-induced dipole alignment, and the resulting poled films of PC-DTCPC-Ph-2 and PC-DTCPC-FPh-2 could retain 95% and 93% of the initial EO activities at 85 °C for more than 500 h respectively.

Facile synthesis and electro-optic activities of new polycarbonates containing tricyanofuran-based nonlinear optical chromophores

Co-reporter:Guowei Deng;Tingting Zhou;Heyan Huang;Jieyun Wu;Jialei Liu;Xinhou Liu;Zhen Zhen;Ling Qiu

Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 13) pp:2841-2849

Publication Date(Web):

DOI:10.1002/pola.26673

ABSTRACT

Two series of novel electro-optic (EO) polycarbonates containing two different kinds of nonlinear optical (NLO) chromophores with tricyanofurane (TCF) electron acceptor have been successfully prepared through the facile polycondensation between diol NLO chromophore and bisphenol A bis(chloroformate). These new polycarbonates which were characterized by ¹H-NMR and Fourier transform infrared exhibited good solubility in common polar organic solvents. They also showed glass transition temperatures (T_g) in the range of 124–156 °C. The morphology studies indicated that these polycarbonates had good film quality before and after corona poling. The EO coefficients (r₃₃) of two polycarbonates films were up to 45 pm/V (PC-TCFC-2) and 75 pm/V (PC-DFTC-3) at the wavelength of 1310 nm. Moreover, good temporal stability of the poling-induced dipole alignment was also achieved, and the resulting poled films of PC-TCFC-2 and PC-DFTC-3 could retain 90 and 80% of the initial EO activities at 85 °C for more than 500 h, respectively. Both EO activity and temporal stability results were better than the guest–host EO polymers containing the same concentration chromophores, which indicated that such kind of polycarbonates could effectively suppress the intermolecular electrostatic interaction and translate microscopic molecular hyperpolarizability into macroscopic EO activity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2841–2849.

Enhanced electro-optic coefficient (r33) in nonlinear optical chromospheres with novel donor structure

Co-reporter:Jieyun Wu, Jialei Liu, Tingting Zhou, Shuhui Bo, Ling Qiu, Zhen Zhen and Xinhou Liu

RSC Advances 2012 vol. 2(Issue 4) pp:1416-1423

Publication Date(Web):16 Dec 2011

DOI:10.1039/C1RA00838B

The synthesis and characterization of new push-pull chromophores A and B, from tricyanofuran (TCF) electron withdrawing and various electron donating moieties, have been demonstrated to compare the roles of donors in electro-optic performance. The crystal structure analyses of the intramolecular hydrogen bond, molecular coplanarity and π–π interactions reveal that A forms cross-stacking, while B forms antiparallel dimer packing, which indicates weaker intermolecular interactions of A than B. Also, the photophysical properties, solvatochromic behavior and Density Functional Theory (DFT) calculations were also investigated. In electro-optic activities, the doped films-A containing chromophore A display an r33 value of 36 pm V−1 at the saturated doping concentration of 40 wt%, while the doped films-B containing B show a maximum r33 value of 16 pm V−1 at the saturated concentration of 25 wt%. High loading density and high r33 value indicate that the chromophore A with julolidinyl-based donor can efficiently reduce the interchromophore electrostatic interactions and enhance the macroscopic optical nonlinearity, showing that chromophore A with julolidinyl-based donor has promising applications in nonlinear optical (NLO) materials.

Synthesis and optical properties of a crosslinkable polymer system containing tricyanofuran-based chromophores with excellent electro-optic activity and thermal stability

Co-reporter:Zhuo Chen;Ling Qiu;Zhen Zhen ;Xinhou Liu

Polymer International 2012 Volume 61( Issue 9) pp:1376-1381

Publication Date(Web):

DOI:10.1002/pi.4216

Abstract

Crosslinkable polymers with side-chain systems were investigated in order to increase the content of nonlinear optical chromophores and improve the stability of oriented chromophores. A series of crosslinkable copolymers having varying concentrations of chromophores with tricyanofuran as an acceptor were successfully synthesized and characterized. The crosslinked electro-optic (EO) polymers revealed the highest EO coefficient (r₃₃) of 47.0 pm V⁻¹ at 1310 nm, which was similar to r₃₃ of uncrosslinked systems. Compared to the uncrosslinked EO polymer systems, the crosslinked ones exhibited significantly enhanced temporal stability. The results of the EO coefficients and thermal properties indicated that the crosslinking effectively improved the stability and did not influence the r₃₃ values. Copyright © 2012 Society of Chemical Industry

Preparation and characterization of the soluble NLO polyarylates with enhanced electro-optic properties

Co-reporter:Liang Wang;Jialei Liu;Zhen Zhen;Xinhou Liu

Polymer Science, Series B 2012 Volume 54( Issue 5-6) pp:297-305

Publication Date(Web):2012 May

DOI:10.1134/S1560090412050041

Three novel nonlinear optical polyarylate polymers were prepared containing one main-chain polymer (mPAR-chr1) and two side-chain polymers (sPAR-chr1, sPAR-chr2) with different kinds of chromophores. The obtained polymers were characterized and evaluated by UV-Vis, 1H NMR, DSC and TGA. All the polymers exhibited excellent thermal stability, film forming ability and good electro-optic (EO) activity. The relationship between EO coefficients (r33) and the chromophore concentration of the three polymers had been also characterized and discussed. There were no obvious differences found in EO activity between main-chain and side-chain polyarylates with the same chromophore (chr1). Due to the stronger electron-withdrawing tricyanopyrroline acceptor and the steric effect of the large dendritic groups of chromophore 2 (chr2), polymer sPAR-chr2 showed the largest EO cofficients (64 pm V−1) in these new polymers.

Synthesis and characterization of a novel indoline based nonlinear optical chromophore with excellent electro-optic activity and high thermal stability by modifying the π-conjugated bridges

Co-reporter:Chaolei Hu, Zhuo Chen, Hongyan Xiao, Zhen Zhen, Xinhou Liu and Shuhui Bo

Journal of Materials Chemistry A 2017 - vol. 5(Issue 21) pp:NaN5118-5118

Publication Date(Web):2017/04/25

DOI:10.1039/C7TC00735C

Two novel second order nonlinear optical (NLO) chromophores based on indoline donors and tricyanofuran (TCF) acceptors linked together via modified polyene π-conjugation bridges have been synthesized in good overall yields and systematically characterized. Thermal stability, optical property and electro-optic property were measured to investigate the effects of the introduced rigid benzene derivative steric hindrance group on the bridge. Besides, density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. After introducing the benzene derivative steric hindrance group into the bridge, chromophore CLH-2 showed very good thermal stability with a decomposition temperature of 250 °C, which was 83 °C higher than chromophore CLH-1 without the isolation group on the bridge. In electro-optic activity, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate the relatively small β values into bulk high EO activities. By doping chromophores CLH-1 and CLH-2 with a high loading of 45 wt% in APC, EO coefficients (r33) of up to 63 and 102 pm V−1 at 1310 nm can be achieved, respectively. The r33 value of the new chromophore CLH-2 was about 1.6 times that of chromophore CLH-1. The high r33 value, good thermal stability and high yield suggest the promising applications of the new chromophore in nonlinear optical areas.

Enhancement of electro-optic properties of bis(N,N-diethyl)aniline based second order nonlinear chromophores by introducing a stronger electron acceptor and modifying the π-bridge

Co-reporter:Hua Zhang, Yuhui Yang, Hongyan Xiao, Fenggang Liu, Fuyang Huo, Lu Chen, Zhuo Chen, Shuhui Bo, Ling Qiu and Zhen Zhen

Journal of Materials Chemistry A 2017 - vol. 5(Issue 27) pp:NaN6712-6712

Publication Date(Web):2017/06/05

DOI:10.1039/C7TC01175J

A series of highly polarizable chromophores y1, y2, yz1 and yz2 based on the same bis(N,N-diethyl)aniline donor, a tricyanofuran acceptor (TCF) and a CF3-Ph-TCF acceptor linked together via thiophene and modified thiophene π-conjugation have been synthesized and are systematically investigated in this paper. Density functional theory (DFT) calculations suggested that the molecular quadratic hyperpolarizability (β) value of the CF3-Ph-TCF based chromophore is 16.8% (yz1 compared with y1) and 46.8% (yz2 compared with y2) larger than those TCF based chromophores. These chromophores showed good thermal stability and their decomposition temperatures were all above 230 °C. Compared with the results obtained from the chromophores (y1 and y2) with the TCF acceptor, the new chromophores (yz1 and yz2) with the CF3-Ph-TCF acceptor show better intramolecular charge-transfer (ICT) absorption (108 nm and 97 nm red-shift). By doping chromophores y1, y2, yz1 and yz2 with a high loading of 25 wt% in amorphous polycarbonate (APC), electro-optic (EO) coefficients (r33) of up to 149, 139, 142 and 252 pm V−1 at 1310 nm can be achieved, respectively. A normalized r33 value of 15.57 × 10−18 pm cc per (V molecules) and an order parameter of (Φ) up to 27.3% was obtained for yz2 possessing the bis(N,N-diethyl)aniline donor, the alkoxy chain modified thiophene bridge and the CF3-Ph-TCF acceptor, which indicated that the structure–property relationship was essential. The high r33 value, good thermal stability and high yields suggest the potential use of new chromophores in a nonlinear optical area.

Synthesis of novel nonlinear optical chromophores: achieving enhanced electro-optic activity and thermal stability by introducing rigid steric hindrance groups into the julolidine donor

Co-reporter:Hua Zhang, Hongyan Xiao, Fenggang Liu, Fuyang Huo, Yanling He, Zhuo Chen, Xinhou Liu, Shuhui Bo, Ling Qiu and Zhen Zhen

Journal of Materials Chemistry A 2017 - vol. 5(Issue 7) pp:NaN1684-1684

Publication Date(Web):2017/01/24

DOI:10.1039/C6TC05414E

A series of chromophores z1–z4 have been synthesized based on julolidine donors modified by four different rigid steric hindrance groups including benzene, 2,3,4,5,6-pentafluorobenzene, 3,5-bis(benzyloxy)benzene and 3,5-bis(2,3,4,5,6-pentafluorobenzoate)benzene, respectively, with the same thiophene bridges and strong tricyanovinyldihydrofuran (TCF) acceptors and with high yields. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Besides, to determine the redox properties of these chromophores, cyclic voltammetry (CV) experiments were performed. All these four chromophores showed superb thermal stabilities with high thermal decomposition temperatures above 265 °C. Most importantly, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate their relatively β values into bulk high EO activities. By doping chromophores z1–z4 with a high loading of 25 wt% in APC, EO coefficients (r33) of up to 99, 104, 97 and 89 pm V−1 at 1310 nm can be achieved, respectively. The normalized r33 value was increased to 6.84 × 10−18 pm cc per (V molecules) for z4 possessing the largest steric hindrance group which indicates the weakest dipole–dipole interaction and highest polarization efficiency. The high r33 value, good thermal stability and high yield suggest the potential use of the new chromophores in nonlinear optical areas.

Synthesis and optical nonlinear properties of novel Y-shaped chromophores with excellent electro-optic activity

Co-reporter:Yuhui Yang, Hongyan Xiao, Haoran Wang, Fenggang Liu, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Journal of Materials Chemistry A 2015 - vol. 3(Issue 43) pp:NaN11431-11431

Publication Date(Web):2015/09/24

DOI:10.1039/C5TC02764K

A series of Y-shaped chromophores A1, A2, B1 and B2 based on the same thiophene π-conjugation and tricyanofuran acceptor (TCF) but with different donors (modified phenothiazine and triphenylamine) have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed excellent thermal stability with their decomposition temperatures all above 270 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-C containing 25 wt% chromophore B1 displayed an r33 value of 72 pm V−1 at 1310 nm, and the doped film-D containing B2 showed a value of 95 pm V−1 at a concentration of 25 wt%. These values are all much higher than the traditional FTC chromophore (39 pm V−1). High r33 values indicated that the special Y structure can reduce intermolecular electrostatic interactions and thus enhance the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of these new chromophores as materials for advanced devices.

Synthesis and optical nonlinear property of Y-type chromophores based on double-donor structures with excellent electro-optic activity

Co-reporter:Yuhui Yang, Huajun Xu, Fenggang Liu, Haoran Wang, Guowei Deng, Peng Si, Heyan Huang, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Journal of Materials Chemistry A 2014 - vol. 2(Issue 26) pp:NaN5132-5132

Publication Date(Web):2014/04/16

DOI:10.1039/C4TC00508B

New Y-type chromophores FTC-yh1 and FTC-yh2 containing bis(N,N-diethyl)aniline as a novel electron-donor, thiophene as a π-conjugated bridge and tricyanofuran (TCF) as an acceptor have been synthesized and systematically investigated in this paper. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. These chromophores showed better thermal stability with their decomposition temperatures all above 240 °C. Most importantly, the high molecular hyperpolarizability of these chromophores can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped film-A containing 25 wt% chromophore FTC-yh1 displayed a value of 149 pm V−1 at 1310 nm, and the doped film-B containing FTC-yh2 showed a value of 143 pm V−1 at the concentration of 25 wt%. These values are almost four times higher than the EO activity of usually reported traditional single (N,N-diethyl)aniline nonlinear optical (NLO) chromophores FTC. High r33 values indicated that the double donors of the bis(N,N-diethyl)aniline unit can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with the good solubility, suggest the potential use of the new chromophores as advanced material devices.

Auxiliary donor for tetrahydroquinoline-containing nonlinear optical chromophores: enhanced electro-optical activity and thermal stability

Co-reporter:Fenggang Liu, Maolin Zhang, Hongyan Xiao, Yuhui Yang, Haoran Wang, Jialei Liu, Shuhui Bo, Zhen Zhen, Xinhou Liu and Ling Qiu

Journal of Materials Chemistry A 2015 - vol. 3(Issue 36) pp:NaN9291-9291

Publication Date(Web):2015/08/06

DOI:10.1039/C5TC01610J

A series of chromophores FTC, L1 and L2 have been synthesized based on three different types of electron donors, including diethylaminophenyl, tetrahydroquinolinyl and N-(4-dimethylaminophenyl) tetrahydroquinolinyl groups respectively, with the same thiophene bridges and strong tricyanovinyldihydrofuran (TCF) acceptors. In particular, the donor part of the chromophore L2 was modified with an additional donor N-(4-dimethylaminophenyl) substituent, resulting in enhanced thermal stability and electro-optic activity. Cyclic voltammetry measurements showed that chromophore L2 had a smaller energy gap than chromophore L1 due to the additional donor. Moreover, density functional theory calculations suggested that the molecular quadratic hyperpolarizability (μβ) value of chromophore L2 is 29% and 44% larger than that of chromophores L1 and FTC, respectively. The doped film containing the chromophore L2 showed an r33 value of 100 pm V−1 at the concentration of 25 wt% which is much higher than the EO activity of the chromophore L1 (57 pm V−1) and two times higher than that of the traditional chromophore FTC (39 pm V−1).

Synthesis and characterization of a novel second-order nonlinear optical chromophore based on a new julolidine donor

Co-reporter:Yuhui Yang, Fenggang Liu, Haoran Wang, Maolin Zhang, Huajun Xu, Shuhui Bo, Jialei Liu, Ling Qiu, Zhen Zhen and Xinhou Liu

Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 37) pp:NaN20215-20215

Publication Date(Web):2014/08/05

DOI:10.1039/C4CP03185G

A new chromophore HK containing the cis,cis-1,7-diethoxy-3-isopropyljulolidine group as a novel electron-donor, thiophene as a π-conjugated bridge and a tricyanofuran (TCF) acceptor has been synthesized and systematically investigated in this paper. Its corresponding chromophore FTC using 4-(diethyl amino)benzyl as the electron donor group was also prepared for comparison. This is the first time that the cis,cis-1,7-diethoxy-3-isopropyljulolidine group was introduced into NLO materials. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gap and first-order hyperpolarizability (β) of the new chromophore. The HOMO–LUMO gap was also investigated by cyclic voltammetry (CV). Upon using the cis,cis-1,7-diethoxy-3-isopropyljulolidine group as the donor, a reduced energy gap of 1.007 eV was obtained compared with chromophore FTC (ΔE = 1.529 eV). The high molecular hyperpolarizability of the new chromophore can be effectively translated into large electro-optic (EO) coefficients (r33) in poled polymers. The doped films containing the new chromophore HK showed a value of 72 pm V−1 at the concentration of 25 wt% at 1310 nm. This value is almost two times higher than the EO activity of the usually reported traditional (N,N-diethyl) aniline nonlinear optical (NLO) chromophore FTC. High r33 values indicated that the new julolidine donor can efficiently improve the electron-donating ability and reduce intermolecular electrostatic interactions, thus enhancing the macroscopic EO activity. These properties, together with good solubility, suggest the potential use of the new chromophore in advanced materials devices.

Nonlinear optical chromophores containing a novel pyrrole-based bridge: optimization of electro-optic activity and thermal stability by modifying the bridge

Co-reporter:Fenggang Liu, Haoran Wang, Yuhui Yang, Huajun Xu, Maolin Zhang, Airui Zhang, Shuhui Bo, Zhen Zhen, Xinhou Liu and Ling Qiu

Journal of Materials Chemistry A 2014 - vol. 2(Issue 37) pp:NaN7795-7795

Publication Date(Web):2014/07/18

DOI:10.1039/C4TC00900B

Three novel second order nonlinear optical chromophores based on julolidinyl donors and tricyanovinyldihydrofuran (TCF) acceptors linked together via modified pyrrole π-conjugation (chromophores A and B) or thiophene moieties (chromophore C) as the bridges have been synthesized and systematically characterized. In particular, the pyrrole moiety bridge has been modified with the electron withdrawing group (–Br, –NO2) substituted benzene ring. The introduction of side phenyl groups to chromophores A and B can increase the thermal and chemical stability and reduce dipole–dipole interactions so as to translate their hyperpolarizability (β) values into bulk EO performance more effectively than chromophore C. Moreover, DFT calculations suggested that the additional electron withdrawing groups in chromophores A and B could increase the β value compared to that of chromophore D without substituted phenyl groups, and they showed different influences on the solvatochromic behavior, thermal stability, and electro-optic activity of the chromophores. EO responses (r33 values) of guest–host polymers containing pyrrole-bridged chromophores were reported. Incorporation of chromophores A and B into APC provided large electro-optic coefficients of 86 and 128 pm V−1 at 1310 nm with a high loading of 30 wt%. Film-C/APC containing 25 wt% of chromophore C provides an EO coefficient of 98 pm V−1.

Nonlinear optical chromophores based on Dewar's rules: enhancement of electro-optic activity by introducing heteroatoms into the donor or bridge

Co-reporter:Huajun Xu, Dan Yang, Fenggang Liu, Mingkai Fu, Shuhui Bo, Xinhou Liu and Yuan Cao

Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 44) pp:NaN29688-29688

Publication Date(Web):2015/10/07

DOI:10.1039/C5CP04959H

In this work, we investigated the enhancement of the electro-optic response by introducing electron-rich heteroatoms as additional donors into the donor or bridge of a conventional second-order nonlinear optical chromophore. A series of chromophores C2–C4 based on the same tricyanofuran acceptor (TCF) but with different heteroatoms in the alkylamino phenyl donor (C2 or C3) or thiophene bridge (C4) have been synthesized and systematically investigated. Density functional theory calculations suggested that chromophores C2–C4 had a smaller energy gap and larger first-order hyperpolarizability (β) than traditional chromophore C1 due to the additional heteroatoms. Single crystal structure analyses and optimized configurations indicate that the rationally introduced heteroatom group would bring larger β and weaker intermolecular interactions which were beneficial for translating molecular β into macro-electro-optic activity in electric field poled films. The electro-optic coefficient of poled films containing 25 wt% of these new chromophores doped in amorphous poly-carbonate afforded values of 83 and 91 pm V−1 at 1310 nm for chromophores C3 and C4, respectively, which are two times higher than that of the traditional chromophore C1 (39 pm V−1). High r33 values indicated that introducing heteroatoms to the donor and bridge of a conventional molecular structure can efficiently improve the electron-donating ability, which improves the β. The long-chain on the donor or bridge part, acting as the isolation group, may reduce inter-molecular electrostatic interactions, thus enhancing the macroscopic EO activity. These results, together with good solubility and compatibility with the polymer, show the new chromophore's potential application in electro-optic devices.

Synthesis of novel nonlinear optical chromophores: achieving excellent electro-optic activity by introducing benzene derivative isolation groups into the bridge

Co-reporter:Chaolei Hu, Fenggang Liu, Hua Zhang, Fuyang Huo, Yuhui Yang, Haoran Wang, Hongyan Xiao, Zhuo Chen, Jialei Liu, Ling Qiu, Zhen Zhen, Xinhou Liu and Shuhui Bo

Journal of Materials Chemistry A 2015 - vol. 3(Issue 44) pp:NaN11604-11604

Publication Date(Web):2015/10/12

DOI:10.1039/C5TC02702K

Three novel second order nonlinear optical (NLO) chromophores based on julolidinyl donors and tricyanofuran (TCF) acceptors linked together via modified polyene π-conjugation with rigid benzene derivative steric hindrance groups (chromophore CL1 and CL2) or unmodified polyene π-conjugation (chromophores CL) moieties as the bridges have been synthesized in good overall yields and systematically characterized. Density functional theory (DFT) was used to calculate the HOMO–LUMO energy gaps and first-order hyperpolarizability (β) of these chromophores. Besides, to determine the redox properties of these chromophores, cyclic voltammetry (CV) experiments were performed. Compared with CL, after introducing benzene derivative steric hindrance groups into the bridge, chromophores CL1 and CL2 had good thermal stabilities with high thermal decomposition temperatures which were 32 °C and 24 °C higher than chromophore CL, respectively. Most importantly, the introduction of rigid steric hindrance groups can effectively reduce dipole–dipole interactions to translate their relatively small β values into bulk high EO activities. By doping chromophores CL, CL1 and CL2 with a high loading of 45 wt% in APC, EO coefficients (r33) of up to 121, 197 and 202 pm V−1 at 1310 nm can be achieved, respectively. The r33 values of new chromophores CL1 and CL2 were about 1.6 times of chromophore CL. The high r33 value, good thermal stability and high yield suggest the potential use of the new chromophores in an nonlinear optical area.