Co-reporter:Lu Zou, Ying-Hui Wang, Ning Sui, Wen-Yu Ji, Ming-Rui Tan, Mou-Cui Ni, Han-Zhuang Zhang
Journal of Luminescence 2017 Volume 190(Volume 190) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.jlumin.2017.05.040
We introduce the preparation process of two-dimensional coumarin 6 (C-6) doped poly-methyl-methacrylate (PMMA) photonic crystals (2D C-6 PCs) in detail. We also cover the 2D C-6 PC with translucent Ag shells. By analyzing the system of 2D C-6 PCs and hemispherical Ag shells, we find that resonance energy transfer and local surface plasmon resonance (LSPR) can affect the photoluminescence (PL) characteristics of 2D C-6 PCs. When we cover the 2D C-6 PC with translucent Ag shell, there is energy transfer between the 2D C-6 PCS and the hemispherical Ag shells. The data of photoluminescence and the corresponding decay curves reveal that resonance energy transfer and localized surface plasmon resonance could effectively manipulate the PL properties of 2D C-6 PCs.
Co-reporter:Xiao-Chun Chi, Mou-Cui Ni, Ying-Hui Wang, Ning Sui, Wen-Yan Wang, Ran Lu, Yan-Qiang Yang, Wen-Yu Ji, Han-Zhuang Zhang
Journal of Photochemistry and Photobiology A: Chemistry 2017 Volume 346(Volume 346) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.jphotochem.2017.06.008
•Pull-push chromophores are comprised of TPA andβ-diketones difluorboron complexes.•The increasing of electron-acceptor improves the PL intensity of compounds.•The photo-excitation dynamics was measured by ultrafast TA spectroscopy.•Three electron-acceptor prolongs the ICT process.Two push-pull compounds, which are comprised of triphenylamine (TPA) (electron donor units) and functionalized β-diketones difluorboron complexes (electron acceptor units) are probed by many spectroscopies, which offers the relationship between electron acceptor and the intrinsic excited state properties of push–pull chromophores. We found that the photoluminescence (PL) intensity would enhance with the number of electron acceptor. Transient absorption (TA) data shows that intramolecular charge transfer (ICT) process really exists in the two molecules after photoexcitation and this process would be prolonged through increasing the electron-acceptor, which would be responsible for the improvement of PL property.Download high-res image (130KB)Download full-size image
Co-reporter:Peng Yang;Yingshu Yang;Yinghui Wang;Jiechao Gao;Ning Sui;Xiaochun Chi;Lu Zou ;Han-Zhuang Zhang
Luminescence 2016 Volume 31( Issue 1) pp:4-7
Publication Date(Web):
DOI:10.1002/bio.3000
Abstract
The photoluminescence (PL) characteristics of CdSe quantum dots (QDs) infiltrated into inverse opal SiO2 photonic crystals (PCs) are systemically studied. The special porous structure of inverse opal PCs enhanced the thermal exchange rate between the CdSe QDs and their surrounding environment. Finally, inverse opal SiO2 PCs suppressed the nonlinear PL enhancement of CdSe QDs in PCs excited by a continuum laser and effectively modulated the PL characteristics of CdSe QDs in PCs at high temperatures in comparison with that of CdSe QDs out of PCs. The final results are of benefit in further understanding the role of inverse opal PCs on the PL characteristics of QDs. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Xiao-Chun Chi, Ying-Shu Yang, Ying-Hui Wang, Jie-Chao Gao, Ning Sui, Hai-Gui Yang, Lu Zou, Zhi-Hui Kang, Han-Zhuang Zhang
Optical Materials 2015 Volume 46() pp:350-354
Publication Date(Web):August 2015
DOI:10.1016/j.optmat.2015.04.043
•The periodic porous structure of TiO2 inverse opal PCs is manifest by SEM image and XRD pattern.•The TiO2 inverse opal PCs manipulate the PL characteristics of CdTe/ZnS QDs.•The TiO2 inverse opal PCs suppress the PL enhancement nonlinearity of CdTe/ZnS QDs.The photoluminescence (PL) characteristics of CdTe/ZnS quantum dots (QDs) infiltrated in TiO2 inverse opal photonic crystals (PCs) are studied in detail. The PL dynamics of QDs show that the PCs could accelerate the PL relaxation rate of QDs as the PL peak of QDs is overlapped with the photonic stop band of PCs. Besides, the PCs could decrease the activation energy of QDs due to its porous structure and suppress the exciton annihilation process of QDs at high excitation intensity, owing to the light scattering effect. The final results are beneficial for people in further understanding the role of inverse opal PCs on manipulating the PL characteristics of QDs.
Co-reporter:Lu Zou, Ning Sui, Ying-Hui Wang, Cheng Qian, Yu-Guang Ma, Han-Zhuang Zhang
Journal of Luminescence 2015 158() pp: 281-285
Publication Date(Web):
DOI:10.1016/j.jlumin.2014.10.016
Co-reporter:Fu-yin Wang, Ying-hui Wang, Ning Sui, Yun-fei Song, Yu-guang Ma and Han-zhuang Zhang
New Journal of Chemistry 2014 vol. 38(Issue 8) pp:3885-3888
Publication Date(Web):07 May 2014
DOI:10.1039/C3NJ01587D
We prepared quantum dots (QDs) based on a conjugated molecule (coumarin 6, C-6), which is considered to be a mesoscopic aggregate, to build a bridge linking the monodisperse state (solution state) and macroscopic aggregates (powder state). Their spectral features, including steady spectral data, dynamic features and fluorescence quantum yields, have been compared in detail. All dynamic data were modelled using the continuous rate distribution function. The final results showed that the fluorescence quantum yield of organic quantum dots based on C-6 gradually decreases as the size of the QDs increases, which may be attributed to enhancement of the rate of non-radiative relaxation, which originates from the aggregation. This is beneficial for further understanding the optical characteristics of conjugated molecules.
Co-reporter:Tian-hao Huang;Zhi-hui Kang;Jin-bo Yao;Ran Lu;Han-zhuang Zhang
Photochemistry and Photobiology 2014 Volume 90( Issue 1) pp:29-34
Publication Date(Web):
DOI:10.1111/php.12154
Abstract
The effects of π-spacer and electron donor groups on the photophysical behaviors of fluorenone-based linear conjugated oligomers have been systemically investigated. Solvent-dependent steady-state measurements exhibit that the fluorene vinylene (FV) spacer and the electron-donating ability of donor group are able to modulate the spectral features of oligomers and the fluorescence quantum yield could decrease with the increasing of the solvent polarity. Meanwhile, quantum chemical calculation simulates their absorption spectra, and analyzes their electron transition components simultaneously. The transient absorption measurements focus on the photoexcitation dynamics of these oligomers in the toluene solution, which show that an intramolecular charge transfer state exists in the relaxation process of excited states, and its generation process could accelerate with the introduction of FV spacer and the enhancement of donor strength.
Co-reporter:Cheng Qian;Yinghui Wang;Yunfei Song;Lu Zou;Yuguang Ma;Yanqiang Yang;Hanzhuang Zhang
Journal of Polymer Science Part B: Polymer Physics 2014 Volume 52( Issue 12) pp:842-847
Publication Date(Web):
DOI:10.1002/polb.23494
ABSTRACT
The effect of the photonic stop bands (PSBs) on the spontaneous emission from tris(8-hydroxyquinolinato)aluminum (Alq3) doped in the beads of polymethylmethacrylate opal photonic crystals (PCs) is investigated in detail. The structure of PSBs in PCs has been analyzed. The steady emission data exhibits that the first- and second-order PSB could effectively influence the spectral characteristics of Alq3 through changing the incident angles. The emission dynamic data is also investigated by using the Kohlrausch strengthened exponential model, which shows that the emission decay rate of Alq3 can be decelerated as the PSB of PC approaches the emission peak of Alq3. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 842–847
Co-reporter:Tian-Hao Huang, Xue-Cong Li, Ying-Hui Wang, Zhi-Hui Kang, Ran Lu, Er-Long Miao, Fei Wang, Gao-Wen Wang, Han-Zhuang Zhang
Optical Materials 2013 Volume 35(Issue 7) pp:1373-1377
Publication Date(Web):May 2013
DOI:10.1016/j.optmat.2013.02.005
We compare the effects of fluorene–ethylene (FE) spacers on the photo-physical properties of fluorenone-based conjugated oligomers. The introduction of FE spacer could modulate the steady-state spectra and weaken the difference between donor-dependent spectral features. Meanwhile, the quantum chemical calculations exhibit that the electron transition mechanism modulated by FE unit is variable with the donor of oligomers. The FE π-spacer mainly rises the HOMO and facilitates the electron delocalization in the fluorene end-capped oligomer, while it lowers the LUMO and enhances the donor effect in the triphenylamine end-capped one. The time-resolved fluorescence measurement exhibits that the difference between donor-dependent excited state lifetimes of oligomers becomes less obvious after the introduction of FE units. Moreover, the nonlinear optical measurements show that the FE spacer is able to improve the two-photon fluorescence efficiency and enhance the two-photon absorption cross-section of oligomers simultaneously, but the difference in two-photon characteristics between oligomers with different donors is also decreased.Highlights► π-Spacer dependent optical properties of fluorenone-based oligomers are studied. ► Fluorene–ethylene (FE) spacer could modulate the steady-state spectra of oligomers. ► FE spacer could increase the TPF efficiency and TPA cross-section of oligomers. ► FE spacer could weaken the difference of donor-dependent optical properties. ► DFT calculations show different modulating mechanisms of FE π-spacer in oligomers.
Co-reporter:Ying-Hui Wang, Jia-Qi Hou, Zhi-Hui Kang, Li-Jing Gong, Tian-Hao Huang, Li-Li Qu, Yu-Guang Ma, Ran Lu, Han-Zhuang Zhang
Chemical Physics Letters 2013 Volume 566() pp:17-20
Publication Date(Web):12 April 2013
DOI:10.1016/j.cplett.2013.02.051
We systemically investigate the photophysical properties of two star-shaped truxene based oligomers with different oligo(fluorene-vinylene) arms (Tr-OFV1 and Tr-OFV3) in solution system. The chemical quantum calculation exhibits that the electronic transition depends on the number of fluorene-vinylene (FV) groups in oligomers. The transient absorption (TA) data exhibits that increasing of FV groups in branch arms could accelerate the relaxation of excited oligomers, and the intensity-dependent exciton–exciton annihilation behavior could appear in the relaxation process of excited Tr-OFV3 and disappear in that of Tr-OFV1, indicating that their photophysical behavior is also closed to the number of FV unit.Graphical abstractHighlights► The spectral feature and transition property of Tr-OFV1 and Tr-OFV3 are studied. ► Their dynamic processes are studied by TA spectroscopy. ► Exciton annihilation is found in Tr-OFV3 solution. ► Tr-OFV3 in solution may stack due to arene–arene interaction.
Co-reporter:Zhi-hui Kang, Ning Sui, Ying-hui Wang, Lu Zou, Cheng Qian, Ran Lu, Han-zhuang Zhang
Journal of Molecular Structure 2013 Volumes 1054–1055() pp:89-93
Publication Date(Web):24 December 2013
DOI:10.1016/j.molstruc.2013.09.018
•Two fluorine (F) based oligomers are synthesized and investigated in detail.•F units modulate the steady-state spectra of oligomers.•DFT calculations analyze molecular structure and the electronic transition.•F units increase the TPF efficiency and the TPA cross-section of oligomers.•F units shorten the lifetime of excited oligomers.Two fluorene based linear conjugated oligomers (P-F-P and F-P-F-P-F) were synthesized where fluorene and phenothiazine groups arrange alternately. In comparison with P-F-P, two fluorene units are introduced into F-P-F-P-F, which could further enhance the π-conjugated system. Spectral measurements exhibit that the absorption and emission spectra of oligomers apparently red shift and the bandgap becomes narrow, due to the extension of π-conjugated system. The quantum chemical calculation is used to analyze their molecular structures and the electronic transition behaviors, indicating that they do not have intramolecular charge transfer character after photoexcitation. Moreover, the increasing of the two-photon absorption cross-section and the shortening of the excited state lifetime would be both attributed to the enhancement of π-conjugated system. The intensity-dependent dynamic measurement shows that no intermolecular interaction occurs in the solution, even though their π-conjugated systems are obviously enhanced.
Co-reporter:Tian-Hao Huang, Dan Yang, Zhi-Hui Kang, Er-Long Miao, Ran Lu, Hui-Peng Zhou, Fei Wang, Gao-Wen Wang, Peng-Fei Cheng, Ying-Hui Wang, Han-Zhuang Zhang
Optical Materials 2013 Volume 35(Issue 3) pp:467-471
Publication Date(Web):January 2013
DOI:10.1016/j.optmat.2012.09.032
Experimental and theoretical studies on the donor-dependent optical characteristics of two D–π–A–π–D type linear fluorenone-based conjugated oligomers are presented, where fluorene and triphenylamine act as the donors, respectively. Because of the strong electron-donating ability, the triphenylamine chromophores lead to red-shifts of spectral features, shorten the excited state lifetime, and enhance the two-photon fluorescence efficiency and two-photon absorption cross-section in comparison with fluorene groups. Quantum chemical calculations provide complementary information regarding the molecular structures and the frontier orbitals, which can provide a deep insight into the electronic structure and properties of oligomers.Graphical abstractHighlights► Donor-dependent optical properties of novel fluorenone-based oligomers are studied. ► Triphenylamine donor red-shifts the steady-state spectra compared to fluorene. ► Compared to fluorene donor, triphenylamine could increase the TPF efficiency. ► Triphenylamine donor could enhance the TPA cross-section compared to fluorene. ► Electronic structure and properties were learned by quantum chemical calculations.
Co-reporter:Tian-Hao Huang, Jia-Qi Hou, Zhi-Hui Kang, Ying-Hui Wang, Ran Lu, Hui-Peng Zhou, Xin Zhao, Yu-Guang Ma, Han-Zhuang Zhang
Journal of Photochemistry and Photobiology A: Chemistry 2013 Volume 261() pp:41-45
Publication Date(Web):1 June 2013
DOI:10.1016/j.jphotochem.2013.04.010
Highlights•π-Spacer dependent optical properties of fluorenone-based oligomers are studied.•Fluorene–ethylene (FE) spacer could modulate the steady-state spectra of oligomers.•DFT calculations confirm the ICT nature in the HOMO–LUMO transition.•FE spacer could increase the TPPL efficiency and TPA cross-section of oligomers.•TA measurement confirms the ICT state exists in the relaxation of excited oligomer.Effect of π-spacer on the optical properties of two novel D-π-A-π-D type fluorenone-based linear conjugated oligomers 2,7-di((E)-2-(10-octyl-10H- phenothiazin-3-yl)vinyl)-9-fluorenone (P-FO-P) and 2,7-di((E)-2-(9,9-dioctyl-7-((E)-2-(10-octyl-10H-phenothiazin-3-yl)vinyl)-9H-fluoren-2-yl)vinyl)-9-fluorenone (P-F-FO-F-P) is investigated, where fluorenone and phenothiazine units act as the electron acceptor and donor moieties, respectively. We observe that the fluorene–ethylene (FE) spacer could modulate the steady-state spectral features. Quantum chemical calculations offer complementary information regarding the frontier orbitals and molecular structures, which confirm that the intramolecular charge transfer (ICT) transition exists in the HOMO–LUMO transitions. Nonlinear optical measurements show that the FE spacer could improve the two-photon photoluminescence yield and enhance the two-photon absorption cross-section. The results of transient absorption measurements exhibit that an ICT state exists in the relaxation process of excited state, and its generation process is obviously accelerated with the introduction of π-spacer.Graphical abstract
![Poly[2,7-(9,9-di-octyl-fluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole]](/data/chemimg/133300/782469-77-6.png)
![Poly[2,7-(9,9-di-octyl-fluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole]](/data/chemimg/133300/782469-77-6_b.png)