Xingguo Chen

Designing a thiophene-fused benzoxadizole as an acceptor to build a narrow bandgap polymer for all-polymer solar cells

Co-reporter:Yang Yang;Jiacheng Wang;Xiaowei Zhan

RSC Advances (2011-Present) 2017 vol. 7(Issue 32) pp:19990-19995

Publication Date(Web):2017/03/31

DOI:10.1039/C7RA02705B

In this work, a thiophene-fused benzoxadizole (BXT) unit was designed as a new acceptor and synthesized for the first time to build a D–A conjugated polymer (PBXT-IDT) with 4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene (IDT) for all polymer solar cells (all-PSCs). Due to the strong electron-withdrawing ability of the BXT unit, PBXT-IDT exhibited a very narrow optical bang gap of 1.43 eV and very strong ICT absorption in the range of 500–850 nm that could be complementary with poly(3-hexylthiophene) (P3TH) in the visible absorption region. Moreover, PBXT-IDT showed relatively low HOMO–LUMO energy levels of −5.33 eV and −3.64 eV, respectively, which can be act as an electron-accepting material to match with P3HT as an electron-donating material for all-PSCs. Therefore, the all-PSC device with a blend of PBXT-IDT and P3HT as the active layer was fabricated and the photovoltaic performances were investigated. The device showed a PCE of 1.09% with a high Voc of 0.84 V and a relatively low energy loss (Eloss) of 0.59 V. This indicates that reasonable structural modification of benzoxadizole (BX) can pave a new way to design a polymer as an electron-accepting material in all-PSCs.

Constructing D–A copolymers based on thiophene-fused benzotriazole units containing different alkyl side-chains for non-fullerene polymer solar cells

Co-reporter:Xiu Jiang;Yang Yang;Jingshuai Zhu;Tsz-Ki Lau;Pei Cheng;Xinhui Lu;Xiaowei Zhan

Journal of Materials Chemistry C 2017 vol. 5(Issue 32) pp:8179-8186

Publication Date(Web):2017/08/17

DOI:10.1039/C7TC02098H

A series of D–A copolymers (P1–P3) based on a thiophene fused benzotriazole (BTAZT) unit and a 4,8-bis(4-fluorothiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (BDTFT) unit have been designed and synthesized as electron-donating materials for non-fullerene polymer solar cells (PSCs) with ITIC as an electron-accepting material. The fusion of a thiophene ring with a BTAZ unit and introduction of a fluorine atom at the BDTT unit have been concurrently performed to regulate the absorption properties and energy levels, and two different alkyl side-chains have also been introduced to BTAZT and BDTFT units, respectively, to investigate the influence of side-chains on the properties of the polymers as well as the photovoltaic performances of the PSCs. The photovoltaic performance evaluation in combination with morphology characterization indicates that the introduction of a 2-ethylhexyl group simultaneously at BTAZT and BDTFT units is favourable for intermolecular π–π interaction that improves the morphologies and crystalline domain of P1:ITIC blend film, thus enhancing the charge mobility and the short-circuit current density (Jsc). But the large steric hindrance of the 2-butyloctyl group to replace the 2-ethylhexyl group at BDTFT (P2) or BTAZT (P3) deteriorates intermolecular interaction that leads to the decrease of charge mobility and poor Jsc. Thus, P1 based PSCs exhibit the highest power conversion efficiency of 7.14% with the best Jsc (14.11 ± 0.27 mA cm−2) and fill factor (63.41 ± 1.46%) among P1–P3 polymers.

Design of a thiophene-fused benzotriazole unit as an electron acceptor to build D–A copolymers for polymer solar cells

Co-reporter:Pengcheng Zhou;Yang Yang;Zhi-Guo Zhang;Yongfang Li

Journal of Materials Chemistry C 2017 vol. 5(Issue 11) pp:2951-2957

Publication Date(Web):2017/03/16

DOI:10.1039/C7TC00083A

A new electron-acceptor, thiophene-fused benzotriazole (BTAZT), is designed for the first time to construct donor–acceptor copolymers with bithienyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDTT) as an electron-donor unit for polymer solar cells (PSCs). Compared with their analogous polymers, which contain a similar conjugated backbone but with the benzotriazole (BTAZ) unit as the acceptor, the BTAZT-based polymers show evident red-shifted absorption with narrower optical band gaps due to the fusion of the thiophene moiety onto the BTAZ unit to further stabilize the quinoid structure of their conjugation backbones. Furthermore, two types of side-chain groups, the alkylcarboxyl group (in PBDTT-BTAZT-1) or alkylcarbonyl group (in PBDTT-BTAZT-2), are introduced to adjust the energy levels and modulate the solubility of the PBDTT-BTAZT based polymers. It is found that the stronger electron-withdrawing ability of the alkylcarboxyl group relative to that of the alkoxycarbonyl group at the α-position of the fused thiophene can further reduce the HOMO energy level to enhance the open voltage (Voc) in the PBDTT-BTAZT-2 based device. PSC devices based on these two polymers as electron-donating materials and a fullerene derivative (PC71BM) as an electron-accepting material are fabricated, and device optimization with additives (DIO or NMP) to modify the morphologies of the active layers and cathode buffer layers (PDIN or PDINO) to modify the cathode interlayers is investigated. The best PCE of approximately 7% is obtained for the PBDTT-BTAZT-1 based device with the DIO additive and PDIN-modified cathode interlayer. Notably, its optimal short circuit current density reaches 14.41 mA cm−2, which is one of the highest values ever reported in BTAZ-based PSCs with a PCBM acceptor. The best PCE of the PBDTT-BTAZT-2 based device also reaches 6.16% with the NMP additive and PDINO-modified cathode interlayer.

Designing a thiophene-fused DPP unit to build an A–D–A molecule for solution-processed solar cells

Co-reporter:Bing Chen, Yang Yang, Pei Cheng, Xingguo Chen, Xiaowei Zhan and Jingui Qin

Journal of Materials Chemistry A 2015 vol. 3(Issue 13) pp:6894-6900

Publication Date(Web):24 Feb 2015

DOI:10.1039/C5TA00294J

A novel thiophene-fused diketopyrrolopyrrole unit (7H-pyrrolo[3,4-a]thieno[3,2-g]indolizine-7,10(9H)-dione, PTI) has been designed as an electron acceptor with the 4,4′-bis-(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]silole (DTS) unit as a donor to construct a new kind of A–D–A molecule (DTS–2TPTI) for solution-processed solar cells. DTS–2TPTI exhibits excellent thermal stability with the decomposition temperature over 400 °C and shows strong absorption from 550 to 750 nm with a high molar extinction coefficient. The optical band gap (Eg) estimated from the absorption edge of the thin film is about 1.44 eV. The highest occupied molecular orbital energy level of DTS–2TPTI determined from CV is about −4.99 eV. Through optimizing the photovoltaic performances of devices, the DTS–2TPTI/PC71BM-based solution processed bulk-heterojunction solar cell with 0.5% DIO as a solvent additive exhibits the best photovoltaic performance with a JSC of 11.28 mA cm−2, VOC of 0.64 V, FF of 59.5% and power conversion efficiency (PCE) of 4.28%, indicating that the PTI unit can act as an efficient acceptor moiety to construct D–A small molecules for OPVs.

New D–π–A organic dyes containing a tert-butyl-capped indolo[3,2,1-jk]carbazole donor with bithiophene unit as π-linker for dye-sensitized solar cells

Co-reporter:Wei Cao, Manman Fang, Zhaofei Chai, Han Xu, Tainan Duan, Zhen Li, Xingguo Chen, Jingui Qin and Hongwei Han

RSC Advances 2015 vol. 5(Issue 42) pp:32967-32975

Publication Date(Web):07 Apr 2015

DOI:10.1039/C5RA02720A

Two new D–π–A organic dyes containing a tert-butyl-capped indolo[3,2,1-jk]carbazole unit as a donor, bithiophene unit as a π-linker and cyanoacrylic acid as an acceptor (CL-10 and CL-11) have been designed and synthesized for dye-sensitized solar cells (DSSCs). By comparison, two dyes exhibit almost the same absorption and electrochemical properties, because the introduction of two hexyl groups at non-ortho β-positions of the 2,2′-bithiophene unit dose not destroy the planarity of the molecular skeleton of CL-11. However, the DSSC devices based on them show very different photovoltaic performances with power conversion efficiency (PCE) of 3.96% for CL-10 and 2.85% for CL-11, which can be attributed to the existence of the hexyl groups in CL-11 that lead to a big decrease of the dye adsorption onto TiO2. The addition of chenodeoxylic acid (CDCA) as a coadsorbant can significantly improve the photovoltaic performances of the DSSCs with a big increase in the PCE for CL-10 (4.68%) and CL-11 (4.66%).

Design of organic dyes for dye-sensitized solar cells: Extending π-conjugation backbone via ‘Click’ reaction to improve photovoltaic performances

Co-reporter:Tainan Duan, Ke Fan, Kan Li, Wei Cao, Cheng Zhong, Xingguo Chen, Tianyou Peng, Jingui Qin

Dyes and Pigments 2015 117() pp: 108-115

Publication Date(Web):

DOI:10.1016/j.dyepig.2015.02.005

Thiophene-Fused Benzothiadiazole: A Strong Electron-Acceptor Unit to Build D–A Copolymer for Highly Efficient Polymer Solar Cells

Co-reporter:Pengcheng Zhou, Zhi-Guo Zhang, Yongfang Li, Xingguo Chen, and Jingui Qin

Chemistry of Materials 2014 Volume 26(Issue 11) pp:3495

Publication Date(Web):May 21, 2014

DOI:10.1021/cm501052a

A novel strong electron-acceptor, thieno[2,3-f]-2,1,3-benzothiadiazole-6-carboxylate (BTT), was first designed and synthesized. By introducing two thienyl groups into BTT and then copolymerizing with thienyl group substituted benzo[1,2-b:4,5-b′]dithiophene (BDTT) unit, a low band gap D–A copolymer (PBTT-TBDTT) was obtained. Compared with its polymer analogue (PBT-TBDTT) with benzothiadiazole (BT) as an acceptor, PBTT-TBDTT exhibits stronger intramolecular charge transfer. Thus, it shows much broader absorption covering almost the whole visible light region (in the range of 300–850 nm) and narrower optical band gap around 1.45 eV with a large IP (ionization potential) at 5.35 eV. The maximum efficiency of PBTT-TBDTT based device reaches 6.07% which is much higher than that of PBT-TBDTT (3.24%), indicating that BTT unit is a promising electron-acceptor moiety to construct low band gap D–A copolymers for PSCs with high photovoltaic performances.

New Kind of Hyperbranched Conjugated Polymers Containing Alkyl-Modified 2,4,6-Tris(thiophen-2-yl)-1,3,5-triazine Unit for Enhancing Two-Photon Absorption

Co-reporter:Pengcheng Zhou, Cheng Zhong, Xingguo Chen, Jingui Qin, Inês Mariz, and Ermelinda Maçôas

Macromolecules 2014 Volume 47(Issue 19) pp:6679-6686

Publication Date(Web):September 16, 2014

DOI:10.1021/ma500914v

Two series of hyperbranched polymers based on alkyl-modified 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine central units linked through fluorene bridges of different lengths have been synthesized via Suzuki coupling. The two series of polymers differ in the position of alkyl substitution within the thienyl group, which can be either closer to the triazine core (P0–P10) or to the fluorene bridge (P0′–P10′). Introduction of a hexyl group at one of the β-positions of the thienyl group improves the solubility of the polymers. A good control over the ratio of triazine and fluorene units allows for the systematic study of the polymer composition effects on the electrochemical, linear, and nonlinear photophysical properties. The nonlinear absorption has been shown to have a noticeable promotion with increasing molar ratio of the triazine core, while the emission quantum yield decreases. The position of alkyl substitution within the thienyl group has a significant effect on the two-photon absorption cross section. Substitution at the β-position of the thienyl group closer to the triazine unit favors nonlinear absorption in the P0–P10 series when compared to the P0′–P10′ series. These polymers perform considerably better as nonlinear absorbers than their unsubstituted analogues.

Synthesis and photovoltaic property of new kind of organic dyes containing 2,2′-bithiophene unit with three electron-donors

Co-reporter:Tainan Duan, Ke Fan, Cheng Zhong, Wuwei Gao, Xingguo Chen, Tianyou Peng, Jingui Qin

Journal of Photochemistry and Photobiology A: Chemistry 2014 Volume 278() pp:39-45

Publication Date(Web):15 March 2014

DOI:10.1016/j.jphotochem.2013.12.019

•Three D–π–A organic dyes containing a π-linker of 2,2′-bithiophene unit linked with three electron-donors have been designed.•The photovoltaic performances of the dyes are characterized and they exhibit relatively high open voltage.•The structure–performance relationship is primarily studied with the aid of theoretical calculation.A series of new organic dyes containing 2,2′-bithiophene unit as a π-linker to connect three electron-donors (including carbazole, DH-45; phenothiazine, DH-46; triphenylamine, DH-47) at 3,4′,5′-positions have been designed and synthesized for dye-sensitized solar cells. The experimental results and theoretic calculations indicated that the large steric hindrance among three electron-donors and 2,2′-bithiophene ring partially destroys the whole molecular coplanarity and weakens intramolecular charge transfer (ICT), which results in the narrow, blue-shift of absorption band and decrease of short-circuit current (Jsc). However, the twisted conjugation skeleton for the dyes is favorable for the spatial charge separation that enhances the open-circuit voltage (Voc). Among them, the dye containing carbazole donating group (DH-45) shows best optimized structure for intramolecular charge transfer (ICT) and exhibits better photovoltaic performances than that of the other two dyes (DH-46 and DH-47).Three new D–π–A conjugated organic sensitizers based on 3,4′,5′-trisubstituted 2,2′-bithiophene were conveniently synthesized. And the photovoltaic performances as well as the structure–property relationship were studied.

Effect of the Longer β-Unsubstituted Oliogothiophene Unit (6T and 7T) on the Organic Thin-Film Transistor Performances of Diketopyrrolopyrrole-Oliogothiophene Copolymers

Co-reporter:Zhengran Yi, Lanchao Ma, Bing Chen, Dugang Chen, Xingguo Chen, Jingui Qin, Xiaowei Zhan, Yunqi Liu, Wen Jie Ong, and Jun Li

Chemistry of Materials 2013 Volume 25(Issue 21) pp:4290

Publication Date(Web):October 15, 2013

DOI:10.1021/cm402381w

Two new diketopyrrolopyrrole-based π-conjugated copolymers (PDPP6T and PDPP7T) have been synthesized by Stille coupling polymerization of 3,6-bis(5′-bromo-[2,2′-bithiophen]-5-yl)-2,5-bis(2-octyldodecyl)pyrrolo-[3,4-c]pyrrole-1,4(2H,5H)-dione with α,α′-bis(trimethylstannyl)-bithiophene and α,α′-bis(trimethylstannyl)-terthiophene, respectively. The impressive high mobility of 3.94 cm2 V–1 s–1 for the polymer with sextetthiophene (6T) and of 2.82 cm2 V–1s–1 for polymer with septetthiophene (7T) is acquired. It is found that the introduction of longer β-unsubstituted oliogothiophene unit in DPP-based copolymers has a great influence on the molecular weight and solubility of the DPP-oligothiophene copolymers that finally affects the organic thin-film transistor (OTFT) performances, indicating that a suitable number of thiophene group in β-unsubstituted oligothiophene exists for such a kind of copolymer to exhibit the best OTFT performances. This work also reveals the significance in the design of D–A copolymers for OTFTs through regulating the balance between π–π stacking of intermolecular chains and molecular weight as well as solubility of the rigid main chain.Keywords: donor−acceptor copolymer; hole mobility; organic thin-film transistors;

Molecular architecture effects in two-photon absorption: from octupolar molecules to polymers and hybrid polymer nanoparticles based on 1,3,5-triazine

Co-reporter:Inês F. A. Mariz, Ermelinda M. S. Maçôas, José M. G. Martinho, Li Zou, Pengcheng Zhou, Xingguo Chen and Jingui Qin

Journal of Materials Chemistry A 2013 vol. 1(Issue 16) pp:2169-2177

Publication Date(Web):18 Feb 2013

DOI:10.1039/C3TB20107D

The two-photon absorption properties of a set of linear copolymers based on the regular alternation of a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine electron-accepting unit with different electron-donating groups attached to two of the thiophen ends were investigated. Comparison of these data with those of the analogous octupolar monomers and hyperbranched polymers allows us to understand the role of the triazine-thiophen core and its molecular architecture in the nonlinear optical properties of these polymeric materials. It is concluded that the arrangement of the push–pull unit into a unidimensional array, as it is the case of the linear copolymer, favours the two-photon absorption cross-section. Hybrid nanoparticles dispersed in water were prepared from selected polymers with two-photon excited fluorescence emission comparable with those of the best performing quantum dots.

A new class of organic dyes containing β-substituted 2, 2′-bithiophenene unit as a π-linker for dye-sensitized solar cells: Structural modification for understanding relationship of structure and photovoltaic performances

Co-reporter:Tainan Duan, Ke Fan, Cheng Zhong, Xingguo Chen, Tianyou Peng, Jingui Qin

Journal of Power Sources 2013 Volume 234() pp:23-30

Publication Date(Web):15 July 2013

DOI:10.1016/j.jpowsour.2013.01.127

A new class of metal-free organic dyes (DH-41–DH-44) containing triphenylamine group as an electron donor, cyanoacrylic acid group as an electron acceptor and a π-linker of 2,2′-bithiophene unit with two hexyl groups at different β-substituted positions have been designed and synthesized. Their photovoltaic performances are characterized experimentally and the structure–performance relationship is explored with the aid of theoretical calculation. Although all the DH dyes show the same structural backbone, changing β-substituted positions of hexyl group at 2,2′-bithiophene unit can alter the molecular coplanarity of conjugated skeleton and the intramolecular charge transfer (ICT) that finally affects the UV–Vis absorption and the photovoltaic performances of the DH dyes. By comparison, the dyes with two hexyl groups at nonortho β-positions of 2,2′-bithiophene unit shows less steric hindrance and better molecular coplanarity that is favorable for improving photovoltaic performances. Among them, DH-44 has the best optimized structure for ICT, so it shows broadened and red-shifted absorption with high molar extinction coefficient, and exhibits excellent photovoltaic performances with high power conversion efficiency of 5.86%, which reaches over 95% of the reference dye N719-based cell fabricated and measured under the same conditions.Graphical abstractNew class of D-π-A structural organic dyes containing a π-linker of 2,2′-bithiophene unit with two hexyl groups at different β-substituted positions have been designed and synthesized. Their photovoltaic performances are characterized experimentally and the structure–performance relationship is explored with the aid of theoretical calculation.Highlights► New D-π-A organic dyes containing a π-linker of 2,2′-bithiophene unit have been obtained. ► The dye with good coplanar structure exhibits excellent photovoltaic performances. ► The structure–performance relationship is explored with the aid of theoretical calculation.

Diketopyrrolopyrrole-Based π-Conjugated Copolymer Containing β-Unsubstituted Quintetthiophene Unit: A Promising Material Exhibiting High Hole-Mobility for Organic Thin-Film Transistors

Co-reporter:Zhengran Yi, Xiangnan Sun, Yan Zhao, Yunlong Guo, Xingguo Chen, Jingui Qin, Gui Yu, and Yunqi Liu

Chemistry of Materials 2012 Volume 24(Issue 22) pp:4350

Publication Date(Web):October 31, 2012

DOI:10.1021/cm302341m

A new diketopyrrolopyrrole-based π-conjugated copolymer (PDPP5T) with high molecular weight has been synthesized by Stille coupling polymerization of 3,6-bis(5-bromothiophen-2-yl)-2,5-bis(2-octyldodecyl)pyrrolo-[3,4-c]pyrrole-1,4(2H,5H)-dione with α,α′-bis(trimethylstannyl)-terthiophene. Its hole mobility without thermal annealing reaches 1.08 cm2 V–1 s–1, and a higher hole mobility of 3.46 cm2 V–1 s–1 is obtained annealed at 200 °C directly in an air atmosphere. This indicates that introducing a longer β-unsubstituted quinquethiophene (5T) unit into the main-chain of DPP-oligothiophene copolymer produces much pronounced p-type behavior and also reduces the steric hindrance of the bulk side-chain groups, which is favorable to enhance the molecular ordering capability at low temperatures and improve the organic thin-film transistors (OTFT) performances. This work demonstrates that PDPP5T is a promising material that can be applied to the cost-effective and large-scale production of OTFTs.Keywords: donor−acceptor copolymer; hole mobility; organic thin-film transistors;

Symmetrical and unsymmetrical multibranched D–π–A molecules based on 1,3,5-triazine unit: synthesis and photophysical properties

Co-reporter:Liqian Zhang, Li Zou, Jiang Xiao, Pengcheng Zhou, Cheng Zhong, Xingguo Chen, Jingui Qin, Inês F. A. Mariz and Ermelinda Maçôas

Journal of Materials Chemistry A 2012 vol. 22(Issue 33) pp:16781-16790

Publication Date(Web):03 Jul 2012

DOI:10.1039/C2JM32323K

A series of V-shaped (D–π–A–π–D) and star-shaped ((D–π–)3A) molecules based on the electron acceptor 1,3,5-triazine core (A) connected to different electron donor groups (D) by a carbon–carbon triple bond as a conjugation bridge (π) has been synthesized. The studied molecules can be separated into symmetrically and unsymmetrically substituted molecules depending on the combination of the electron donating branches connected to the triazine core. Their photophysical properties are characterized experimentally and the structure–properties relationship is analysed with the aid of theoretical calculations. The symmetrically branched 1,3,5-triazine-based molecules exhibit similar UV-vis absorption to the corresponding linear molecules, but an obvious blue-shift in the emission is observed with increasing dimensionality. The absorption of the unsymmetrically branched 1,3,5-triazine-based molecules is clearly localized on a specific branch, suggesting a weak interbranch conjugation in the ground state. Emission is mainly controlled by the branch with the lowest energy excited state, which corresponds to the one with the largest intramolecular charge transfer (ICT) effect. The two-photon absorption properties of selected molecules are studied. They exhibit strong two-photon absorption activities and a modest interbranch conjugation effect, enhancing the TPA cross-section beyond the additive effect of increasing branch number.

Triphenylamine-based organic dyes containing a 1,2,3-triazole bridge for dye-sensitized solar cells via a ‘Click’ reaction

Co-reporter:Tainan Duan, Ke Fan, Yang Fu, Cheng Zhong, Xingguo Chen, Tianyou Peng, Jingui Qin

Dyes and Pigments 2012 Volume 94(Issue 1) pp:28-33

Publication Date(Web):July 2012

DOI:10.1016/j.dyepig.2011.11.008

Three new organic dyes with one, two and three branched D–π–A structures derived from an electron donating triphenylamine core and connected by 1,2,3-triazole group to an electron deficient cyanoacrylate system have been conveniently synthesized via a ‘Click’ reaction. It was found that all three dyes show UV–vis absorptions in the 300–500 nm range with high molar extinction coefficients. A red-shift of UV–vis absorption band was observed in the solid thin film compared with the dioxane solution. Dye-sensitized solar cell devices based on the dyes were fabricated and tested. The one branched triphenylamine-based dye exhibits the highest energy conversion efficiency. Increase of the branched D–π–A structure around the triphenylamine core results in the decrease of energy conversion efficiency of the dyes, which can be attributed to less attachment of the dyes onto TiO2 photoanode with the enlarged molecular size of the corresponding multibranched structure.New organic dyes based on triphenylamine core have been synthesized via a ‘Click’ reaction. The introduction of 1,2,3-triazole bridge enhances the Voc and fill factor of the DSSCs, and the increment of branched D–π–A structure results in the decrease of energy conversion efficiency.Highlights► Three new triphenylamine-based organic dyes were conveniently synthesized via a “Click” reaction. ► The bridging 1,2,3-triazole group has been introduced into dyes for DSSCs for the first time. ► The photovoltaic performance was discussed using results from the experimental study and DFT calculations.

New organic dyes containing tert-Butyl-capped N-Arylcarbazole moiety for Dye-sensitized solar cells

Co-reporter:Tainan Duan, Ke Fan, Cheng Zhong, Tianyou Peng, Jingui Qin and Xingguo Chen

RSC Advances 2012 vol. 2(Issue 18) pp:7081-7086

Publication Date(Web):30 May 2012

DOI:10.1039/C2RA20777J

Two new organic dyes with tert-butyl-capped N-arylcarbazole as a donor, cyanoacrylic acid as an acceptor and a bithiophene unit as a π-linker (DH-11 and DH-12) have been synthesized and characterized for dye-sensitized solar cells (DSSCs). It is found that the introduction of tert-butyl-capped N-arylcarbazole as an electron donor can efficiently suppress the intermolecular aggregation and improve the photovoltaic performances. The DSSC devices based on the dyes show relatively high power conversion efficiency of 3.67 and 3.75% for DH-11 and DH-12, respectively, which reaches over 65% of the reference dye N719-based cell fabricated and measured under the same conditions. This infers that the tert-butyl-capped N-arylcarbazole unit is a promising electron-donor that can be employed to design metal-free sensitizers with a new structural skeleton.

π-conjugated polymers containing pendant Mn12 cluster: Synthesis and physical properties

Co-reporter:Xiaobing Yan, Sanping Cheng, Linhao Sun, Xingguo Chen, Jingui Qin

Polymer 2012 Volume 53(Issue 1) pp:241-247

Publication Date(Web):5 January 2012

DOI:10.1016/j.polymer.2011.11.027

In this paper two conjugated polymers containing polyfluorene chain with pendant carboxyl group (P1 and P2) are synthesized via Suzuki reaction, and then two corresponding polymers containing the pendant Mn12 cluster core (Mn12-P1 and Mn12-P2) are obtained through exchange of the pendant carboxyl group in the polymers with acetate ligand of Mn12-Ac. All the polymers show similar UV–vis absorption spectra with maximum peak at 388 nm and fluorescence emission spectra with maximum peak at 419 nm and a shoulder at 443 nm that can be attributed to the polyfluorene chain. The cyclic voltammetry measurement indicates that Mn12-P1 or Mn12-P2 exhibit similar electrochemical behavior to that of the corresponding P1 or P2. These indicate that the introduction of Mn12 cluster at the side-chain of the conjugated polymers has little influence on the photophysical and electrochemical properties of the conjugated main-chain. However, compared with pristine Mn12-Ac the magnetic properties of the modified Mn12 cluster has been changed after substitution of acetate group by the pendant carboxyl group of the polymer. Both of the Mn12 clusters modified by the conjugated polymer (Mn12-P1 and Mn12-P2) show paramagnetism in the range of 2–300 K, and no SMM magnetic behavior is observed at low temperature.New kind of magnetic polymers are obtained via the modification of Mn12 cluster by π-conjugated polymers. Although the SMM magnetic behavior of Mn12 core has been changed after the ligand exchange of Mn12-Ac, the introduction of Mn12 core at the side-chain has little influence on the photophysical properties of the conjugated main-chain.

Synthesis and photophysical properties of hyperbranched polyfluorenes containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine as the core

Co-reporter:Li Zou, Yan Liu, Nan Ma, Ermelinda Maçôas, José M. G. Martinho, Mika Pettersson, Xingguo Chen and Jingui Qin

Physical Chemistry Chemical Physics 2011 vol. 13(Issue 19) pp:8838-8846

Publication Date(Web):31 Mar 2011

DOI:10.1039/C0CP03014G

A series of new hyperbranched polymers containing a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core unit and polyfluorene chain arms have been synthesized via Suzuki coupling, and characterized by NMR, IR and GPC. All the polymers exhibit good thermal stability with a high decomposition temperature. By changing the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio the UV-vis absorption and emission spectra can be partially tuned. It has been found that the polymers containing a low ratio of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine units (P1–P3) have an absorption maximum around 385 nm, localized in the polyfluorene chain, and a shoulder around 425 nm ascribable to a charge transfer state involving the fluorene and the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core. Increasing the molar ratio of the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit enhances the charge transfer band which becomes dominant for P4. The LUMO level of these polymers is relatively low due to the electron affinity of the triazine group. The polymers show dual emission, with a structured band in the blue (410–440 nm), attributed to the polyfluorene, and a broad band in the red (470–500 nm) associated with the charge transfer state. All the polymers exhibit two-photon absorption activity in the range of 660 to 900 nm with the maximum two-photon absorption (TPA) cross-section red-shifted from the corresponding linear absorption. The values of the TPA cross-sections vary from 1000 to 5000 GM, following the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio.

A linear Cu (II) coordination polymer based on a simple click chelator

Co-reporter:Yang Fu, Hua Li, Xingguo Chen, Jingui Qin

Inorganic Chemistry Communications 2011 Volume 14(Issue 1) pp:268-270

Publication Date(Web):January 2011

DOI:10.1016/j.inoche.2010.11.011

A linear Cu(II) coordination polymer [CuCl2Cu(N3)2 L] (L = 2-[(4-phenyl-5 H-1,2,3-triazole)methyl]pyridine) (1) has been synthesized. The crystal structure is determined by the single crystal X-ray diffraction. It is found that Cu(II) cations in 1 are bridged with four types of ligand or anions, 1,2,3-triazole group in L, two different End-Open azides and a tri-coordinated chloride anion. Among them L simultaneously behaves as a chelator and a bridge, in which the N2 and N3 atoms of 1, 2, 3-triazole group coordinate to different Cu(II) cations. The Cu(II) centers exhibit two different coordination geometries in 1. One Cu(II) cation adopts a distorted octahedral geometry and the other adopts a distorted square pyramidal geometry. The magnetic measurement indicates that 1 exhibits the paramagnetism with anti-ferromagnetic interaction among the Cu(II) spins.A linear coordination polymer, Cu(Cl)2Cu(N3)2L (L = 2-[(4-phenyl-5H-1,2,3-triazole) methyl]pyridine) (1), has been synthesized. In 1, L behaves simultaneously as a chelator and a bridge, and another two types of bridging ligands, end-open azide and chloride anion, also participate in coordination. 1 exhibits paramagnetism with anti-ferromagnetic interaction among the Cu(II) spins.Research Highlights► Simple click chelator L (L = 2-[(4-Phenyl-5 H-1, 2, 3-triazole) methyl] pyridine) compose linear coordination polymer [CuCl2Cu(N3)2 L]. ► L behaves simultaneously as both a chelator and a bridging ligand through the 1, 2, 3-triazole group. ► Both N2 and N3 in L coordinated to different copper (II). ► The N2 is more effective than N3 in the polymeric structure. ►Two EO bridged azido anions and a tri-coordinated chloride anion also involved in complex.

Synthesis and magnetic properties of layered MnPSxSe3−x (0x3) and corresponding intercalation compounds of 2,2′-bipyridine

Co-reporter:Xiaobing Yan, Xingguo Chen, Jingui Qin

Materials Research Bulletin 2011 46(2) pp: 235-238

Publication Date(Web):

DOI:10.1016/j.materresbull.2010.11.012

Synthesis of Click-Chelator via Cu(I)-Catalyzed Alkyne-Azide Cycloaddition

Co-reporter:Yang Fu;Yan Liu;Xiaoping Fu;Li Zou;Hua Li;Ming Li; Dr. Xingguo Chen;Jingui Qin

Chinese Journal of Chemistry 2010 Volume 28( Issue 11) pp:2226-2232

Publication Date(Web):

DOI:10.1002/cjoc.201090368

Abstract

The click-ligands based on 1,2,3-triazole and pyridine unit has been synthesized via Cu(I)-catalyzed alkyne-azide cycloaddition from corresponding organic azides and terminal alkynes. The ligand structure was characterized by NMR, IR and elemental analysis as well as single crystal diffractions. The single crystal structure of the complexes from two different ligands coordinating to Cu(II) and Co(II) ions indicated that the N(2) atom in 1,2,3-triazole unit can act as an efficient donor to metals through the rational molecular design.

New linear π-conjugated polymers via Suzuki coupling of (1Z, 3Z)-1,4-dibromo-1,4-diaryl-buta-1,3-diene with aromatic diborates: Synthesis and photophysical properties

Co-reporter:Yan Liu, Xingguo Chen, Jingui Qin, Gui Yu, Yunqi Liu

Polymer 2010 Volume 51(Issue 16) pp:3730-3735

Publication Date(Web):22 July 2010

DOI:10.1016/j.polymer.2010.06.003

Star-Shaped D--A Molecules Containing a 2,4,6-Tri(thiophen-2-yl)-1,3,5-triazine Unit: Synthesis and Two-Photon Absorption Properties

Co-reporter:Li Zou;Zijun Liu;Xiaobing Yan;Yan Liu;Yang Fu;Jun Liu;Zhenli Huang;Jingui Qin

European Journal of Organic Chemistry 2009 Volume 2009( Issue 32) pp:5587-5593

Publication Date(Web):

DOI:10.1002/ejoc.200900641

Abstract

A series of new star-shaped donor-π-acceptor (D-π-A) molecules containing the 2,4,6-tri(thiophen-2-yl)-1,3,5-triazine unit were synthesized and characterized. The 1,3,5-triazine group, as a strong electron-accepting center, is connected to three electron-donating end groups through π-conjugated bridges. As a result of the coexistence of the electron acceptor and donor, these compounds show reversible or quasireversible redox behavior. Through changing the peripheral end group the optical properties can be modified. All compounds exhibit two-photon absorption activity in the range of 720–880 nm and show large two-photon absorption cross sections that are closely related to the intramolecular charge transfer and π-conjugated length of the molecule.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The synthesis and magnetism of mixed metal hexathiohypodiphosphate (MnxCd1−xPS3) system and its intercalates

Co-reporter:Xuan Zhang, Xu Su, Xingguo Chen, Jingui Qin, Makoto Inokuchi

Microporous and Mesoporous Materials 2008 Volume 108(1–3) pp:95-102

Publication Date(Web):1 February 2008

DOI:10.1016/j.micromeso.2007.03.031

The mixed metal hexathiohypodiphosphate MnxCd1−xPS3 (0 < x ⩽ 1) system and its two new series of related intercalates based on tetraethylammonium (Et4N+) (Series A) and 2,2′-bipyridine (bipy) (Series B) have been synthesized and characterized by X-ray powder diffraction, infrared spectroscopy and element analysis, respectively. All MnxCd1−xPS3 (x = 0.18, 0.52, 0.82 and 1.0) compounds have the similar structure to pure MnPS3. In series A, the lattice expansion (Δd) of intercalates (Mn0.86PS3(Et4N)0.28, A1; Mn0.68Cd0.17PS3(Et4N)0.30, A2; Mn0.36Cd0.47PS3(Et4N)0.34, A3; Mn0.05Cd0.79PS3(Et4N)0.32, A4) is about 5.0 Å, and the charge balance of insertion of Et4N+ cation into layered space of the host are maintained by the departure of intralayered Mn2+ ions of the host. However, in series B the intralayered Cd2+ ions are removed by the insertion of 2,2′-bipyridine into layered space of the host, and the lattice expansion (Δd) of the intercalates (Mn0.77PS3(bipy)0.44, B1; Mn0.73Cd0.05PS3(bipy)0.44, B2; Mn0.43Cd0.34PS3(bipy)0.46, B3; Mn0.18Cd0.54PS3(bipy)0.56, B4) is about 9.0 Å. The magnetic properties are studied with SQUID. It is found that the magnetic properties of MnxCd1−xPS3 system are changed from antiferromagnetism to paramagnetism with the increase of Cd2+ ions. In Series A and B, the intercalates (A1–2 and B1–2) that have less Cd2+ ions exhibit bulk spontaneous magnetization at low-temperature. And the intercalates (A3–4 and B3–4), which have more Cd2+ ions, only exhibit paramagnetism. Obviously, the existence of diamagnetic Cd2+ ions dilutes the magnetic interaction of Mn2+ ions in MnxCd1−xPS3 system and its related intercalates. It is also found that either the departure of intralayered Mn2+ or Cd2+ ions from the host can induce the ferromagnetization at low-temperature when the content of Mn2+ ions is over 0.70.

Linear -conjugated polymers containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit: Synthesis and optical properties

Co-reporter:Li Zou;Yang Fu;Xiaobing Yan;Jingui Qin

Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 2) pp:702-712

Publication Date(Web):

DOI:10.1002/pola.22418

Abstract

Some linear π-conjugated polymers containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit were synthesized via Sonogashira or Suzuki reaction for the first time and characterized by IR, NMR, and GPC. Because of the introduction of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit into π-conjugated system, all polymers exhibited good thermal stability with high decomposition temperature. Their optical and electrochemical properties were investigated. Based on the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit linked with different aromatic rings, the polymers showed the tunable fluorescence from blue to blue-green emission with satisfied quantum yield. Cyclic voltammetry measurement indicated that the LUMO and HOMO levels of the polymers could be adjustable through the main-chain structural modification. All polymers had low LUMO level (−2.86 to −3.06 eV) due to the high-electron affinity of triazine unit. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 702–712, 2008

An inorganic–organic intercalated nanocomposite, BEDT-TTF into layered MnPS3

Co-reporter:Huiqiong Zhou;Li Zou

Journal of Inclusion Phenomena and Macrocyclic Chemistry 2008 Volume 62( Issue 3-4) pp:

Publication Date(Web):2008 December

DOI:10.1007/s10847-008-9470-0

In this paper we report the synthesis and magnetic properties of an inorganic–organic hybrid, Mn0.84PS3(BEDT-TTF)0.35 (BEDT-TTF = bis(ethylenedithio) tetrathiafulvalene), which is obtained by the intercalation of pre-intercalation compound Mn0.90PS3(Phen)0.32 (Phen = 1,10-phenanthroline) with (BEDT-TTF)2Ix. The lattice spacing expansion (Δd) of 4.0 Å compared with the pristine MnPS3 indicates that the molecular plane of BEDT-TTF is arranged parallel to the host layer. From the magnetic measurements it was found that two magnetic phase transitions occur. Above 50 K it shows paramagnetism in well agreement with Curie–Weiss law. Around 40 K it exhibits spin-glass transition and at 5 K a ferrimagnetic phase transition occurs, which is confirmed by M–H at different temperatures.

Synthesis, characterization and magnetic properties of transition metal salen complexes intercalated into layered MnPS3

Co-reporter:Xuan Zhang, Huiqiong Zhou, Xu Su, Xingguo Chen, Chuluo Yang, Jingui Qin, Makoto Inokuchi

Journal of Alloys and Compounds 2007 Volume 432(1–2) pp:247-252

Publication Date(Web):25 April 2007

DOI:10.1016/j.jallcom.2006.05.107

Three new intercalation compounds based on the cationic complexes [M(salen)]+ (M = Mn3+, Fe3+, Co3+; salen = N,N′-ethylene-bis(salicylaldimine)) and the layered MnPS3 have been synthesized and characterized by XRD, IR, TGA and elemental analysis. Compared with pure MnPS3, the lattice expansion (Δd) of 9.6–9.7 Å for [Fe(salen)]0.56Mn0.72PS3·0.5H2O and [Mn(salen)]0.26Mn0.87PS3·0.5H2O indicates that the guest molecular is arranged with its C2 axis in a titled way to the host layer. While [Co(Salen)]0.70Mn0.65PS3·H2O was expanded by about 14 Å suggesting that the guest is arranged in another way with its C2 axis parallel to host layer. Their magnetic properties were studied with SQUID. The intercalate [Fe(salen)]0.56Mn0.72PS3·0.5H2O and [Mn(salen)]0.26Mn0.87PS3·0.5H2O exhibit magnetic transition from paramagnetism to ferrimagnetism at about 35 K. However, [Co(salen)]0.70Mn0.65PS3·H2O only exhibits paramagnetism in the whole range of the measured temperature. All three intercalates do not show spin crossover behavior.

The intercalation of transition metal salen complexes into layered MoS2

Co-reporter:Xuan Zhang;Yang Fu

Journal of Inclusion Phenomena and Macrocyclic Chemistry 2007 Volume 59( Issue 3-4) pp:217-222

Publication Date(Web):2007 December

DOI:10.1007/s10847-007-9311-6

Exfoliation-restack method has been employed to synthesize the intercalation compounds based on the cationic complexes [M(Salen)]+ (M = Mn3+, Fe3+, Co3+; Salen = N, N′-ethylene-bis(salicylaldimine)) into the layered MoS2. Their conductivity is in the range of 0.04–0.1 S/cm, which is much higher than the pristine MoS2. Magnetic measurement indicated that the intercalation compounds [Mn(Salen)]0.18MoS2 · 0.25H2O and [Fe(Salen)]0.12MoS2 · 0.3H2O exhibit the temperature-dependent paramagnetism, which obviates from the Curie–Weiss law due to the temperature-independent paramagnetism of the exfoliated MoS2 slabs, while [Co(Salen)]0.14MoS2 · 0.5H2O exhibits the almost temperature-independent paramagnetism. All three intercalation compounds do not show magnetic spin crossover behavior.

Symmetrical and unsymmetrical multibranched D–π–A molecules based on 1,3,5-triazine unit: synthesis and photophysical properties

Co-reporter:Liqian Zhang, Li Zou, Jiang Xiao, Pengcheng Zhou, Cheng Zhong, Xingguo Chen, Jingui Qin, Inês F. A. Mariz and Ermelinda Maçôas

Journal of Materials Chemistry A 2012 - vol. 22(Issue 33) pp:

Publication Date(Web):

DOI:10.1039/C2JM32323K

Synthesis and photophysical properties of hyperbranched polyfluorenes containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine as the core

Co-reporter:Li Zou, Yan Liu, Nan Ma, Ermelinda Maçôas, José M. G. Martinho, Mika Pettersson, Xingguo Chen and Jingui Qin

Physical Chemistry Chemical Physics 2011 - vol. 13(Issue 19) pp:NaN8846-8846

Publication Date(Web):2011/03/31

DOI:10.1039/C0CP03014G

A series of new hyperbranched polymers containing a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core unit and polyfluorene chain arms have been synthesized via Suzuki coupling, and characterized by NMR, IR and GPC. All the polymers exhibit good thermal stability with a high decomposition temperature. By changing the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio the UV-vis absorption and emission spectra can be partially tuned. It has been found that the polymers containing a low ratio of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine units (P1–P3) have an absorption maximum around 385 nm, localized in the polyfluorene chain, and a shoulder around 425 nm ascribable to a charge transfer state involving the fluorene and the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core. Increasing the molar ratio of the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit enhances the charge transfer band which becomes dominant for P4. The LUMO level of these polymers is relatively low due to the electron affinity of the triazine group. The polymers show dual emission, with a structured band in the blue (410–440 nm), attributed to the polyfluorene, and a broad band in the red (470–500 nm) associated with the charge transfer state. All the polymers exhibit two-photon absorption activity in the range of 660 to 900 nm with the maximum two-photon absorption (TPA) cross-section red-shifted from the corresponding linear absorption. The values of the TPA cross-sections vary from 1000 to 5000 GM, following the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio.

Designing a thiophene-fused DPP unit to build an A–D–A molecule for solution-processed solar cells

Co-reporter:Bing Chen, Yang Yang, Pei Cheng, Xingguo Chen, Xiaowei Zhan and Jingui Qin

Journal of Materials Chemistry A 2015 - vol. 3(Issue 13) pp:NaN6900-6900

Publication Date(Web):2015/02/24

DOI:10.1039/C5TA00294J

A novel thiophene-fused diketopyrrolopyrrole unit (7H-pyrrolo[3,4-a]thieno[3,2-g]indolizine-7,10(9H)-dione, PTI) has been designed as an electron acceptor with the 4,4′-bis-(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]silole (DTS) unit as a donor to construct a new kind of A–D–A molecule (DTS–2TPTI) for solution-processed solar cells. DTS–2TPTI exhibits excellent thermal stability with the decomposition temperature over 400 °C and shows strong absorption from 550 to 750 nm with a high molar extinction coefficient. The optical band gap (Eg) estimated from the absorption edge of the thin film is about 1.44 eV. The highest occupied molecular orbital energy level of DTS–2TPTI determined from CV is about −4.99 eV. Through optimizing the photovoltaic performances of devices, the DTS–2TPTI/PC71BM-based solution processed bulk-heterojunction solar cell with 0.5% DIO as a solvent additive exhibits the best photovoltaic performance with a JSC of 11.28 mA cm−2, VOC of 0.64 V, FF of 59.5% and power conversion efficiency (PCE) of 4.28%, indicating that the PTI unit can act as an efficient acceptor moiety to construct D–A small molecules for OPVs.

Design of a thiophene-fused benzotriazole unit as an electron acceptor to build D–A copolymers for polymer solar cells

Co-reporter:Pengcheng Zhou, Yang Yang, Xingguo Chen, Zhi-Guo Zhang and Yongfang Li

Journal of Materials Chemistry A 2017 - vol. 5(Issue 11) pp:NaN2957-2957

Publication Date(Web):2017/02/22

DOI:10.1039/C7TC00083A

A new electron-acceptor, thiophene-fused benzotriazole (BTAZT), is designed for the first time to construct donor–acceptor copolymers with bithienyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDTT) as an electron-donor unit for polymer solar cells (PSCs). Compared with their analogous polymers, which contain a similar conjugated backbone but with the benzotriazole (BTAZ) unit as the acceptor, the BTAZT-based polymers show evident red-shifted absorption with narrower optical band gaps due to the fusion of the thiophene moiety onto the BTAZ unit to further stabilize the quinoid structure of their conjugation backbones. Furthermore, two types of side-chain groups, the alkylcarboxyl group (in PBDTT-BTAZT-1) or alkylcarbonyl group (in PBDTT-BTAZT-2), are introduced to adjust the energy levels and modulate the solubility of the PBDTT-BTAZT based polymers. It is found that the stronger electron-withdrawing ability of the alkylcarboxyl group relative to that of the alkoxycarbonyl group at the α-position of the fused thiophene can further reduce the HOMO energy level to enhance the open voltage (Voc) in the PBDTT-BTAZT-2 based device. PSC devices based on these two polymers as electron-donating materials and a fullerene derivative (PC71BM) as an electron-accepting material are fabricated, and device optimization with additives (DIO or NMP) to modify the morphologies of the active layers and cathode buffer layers (PDIN or PDINO) to modify the cathode interlayers is investigated. The best PCE of approximately 7% is obtained for the PBDTT-BTAZT-1 based device with the DIO additive and PDIN-modified cathode interlayer. Notably, its optimal short circuit current density reaches 14.41 mA cm−2, which is one of the highest values ever reported in BTAZ-based PSCs with a PCBM acceptor. The best PCE of the PBDTT-BTAZT-2 based device also reaches 6.16% with the NMP additive and PDINO-modified cathode interlayer.

Molecular architecture effects in two-photon absorption: from octupolar molecules to polymers and hybrid polymer nanoparticles based on 1,3,5-triazine

Co-reporter:Inês F. A. Mariz, Ermelinda M. S. Maçôas, José M. G. Martinho, Li Zou, Pengcheng Zhou, Xingguo Chen and Jingui Qin

Journal of Materials Chemistry A 2013 - vol. 1(Issue 16) pp:NaN2177-2177

Publication Date(Web):2013/02/18

DOI:10.1039/C3TB20107D

The two-photon absorption properties of a set of linear copolymers based on the regular alternation of a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine electron-accepting unit with different electron-donating groups attached to two of the thiophen ends were investigated. Comparison of these data with those of the analogous octupolar monomers and hyperbranched polymers allows us to understand the role of the triazine-thiophen core and its molecular architecture in the nonlinear optical properties of these polymeric materials. It is concluded that the arrangement of the push–pull unit into a unidimensional array, as it is the case of the linear copolymer, favours the two-photon absorption cross-section. Hybrid nanoparticles dispersed in water were prepared from selected polymers with two-photon excited fluorescence emission comparable with those of the best performing quantum dots.

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