Towards an understanding of structure–property relationships in hole-transport materials: The influence of molecular conformation on oxidation potential in poly(aryl)amines
摘要:
我们结合单晶 X 射线衍射、电化学和光谱电化学方法以及 DFT 计算,评估了分子构象对几种 TPD 型空穴传输材料的氧化(电离)电位和电子结构的影响。通过电子(感应)效应和热力学效应的结合,甲基的引入可用于调整这些分子物种的电离电势,同时发现分子框架中联苯部分的构象在决定与分子水平电荷传输过程相关的马库斯型重组能方面起着最大的作用。
Blue two-photon excited fluorescence of several D-π-D, A-π-A, and D-π-A compounds featuring dimesitylboryl acceptor
作者:Du Xia Cao、Zhi Qiang Liu、Qi Fang、Gui Bao Xu、Gang Xue、Guo Qun Liu、Wen Tao Yu
DOI:10.1016/j.jorganchem.2004.04.006
日期:2004.7
organic compounds with fluorene as π bridge and dimesitylboryl group as electron acceptor, which show strong two-photonexcited blue fluorescence, have been synthesized and structurally investigated. The symmetric A-π-A type of compound exhibits the shortest wavelength of two-photonexcitedfluorescence (TPEF) at λem=405 nm under the excitation of λex=730 nm; the unsymmetric D-π-A type of compound with
几种供体-供体(D-π-D),受体-供体(A-π-A)和供体-供体(D-π-A)类型的有机化合物,以芴为π桥和合成并在结构上研究了以二烯丙基氯为电子受体的双光子激发蓝色荧光。化合物的对称A-π-A型在具有两个光子激发荧光(TPEF)的最短波长λ EM =激发下405nm的λ EX = 730纳米; 与二苯基氨基作为供体化合物的不对称d-π-A型表现出在蓝色区域中的最强烈的TPEF(λ EM = 484纳米)与双光子吸收425 GM的下横截面λ EX = 800纳米。
2,7-Diaminofluorene-Based Organic Dyes for Dye-Sensitized Solar Cells: Effect of Auxiliary Donor on Optical and Electrochemical Properties
作者:Abhishek Baheti、Prachi Singh、Chuan-Pei Lee、K. R. Justin Thomas、Kuo-Chuan Ho
DOI:10.1021/jo200501b
日期:2011.6.17
New organic dyes containing a diarylaminofluorene unit as an electron donor and cyanoacrylic acid as acceptor and anchoring group in a donor-pi-donor-pi-acceptor architecture have been synthesized and characterized as sensitizers for nanocrystalline TiO2-based dye-sensitized solar cells. They have shown three major electronic absorptions originating from the pi-pi* and charge-transfer transitions covering the broad visible range (250-550 nm) in solution. The charge-transfer transition of the dyes exhibited negative solvatochromism, suggesting a polarized ground state. They have also displayed acidochromism in solution owing to the presence of a protonation-deprotonation equilibrium. On comparison with the triphenylamine and carbazole-based parent dyes (E)-2-cyano-3-(4-(diphenylamino)phenyl)acrylic acid and (E)-2-cyano-3-(9-ethyl-9H-carbazol-3-yl)acrylic acid they exhibited longer wavelength absorptions and facile oxidation, indicating the stronger electron-donating ability of the auxiliary chromophores. In addition, they exhibited nearly two times larger light-to-electron conversion efficiency under simulated AM 1.5 G irradiation (100 mW cm(-2)) with an aperture mask when compared to the parent dyes. Among the new dyes, the one containing the naphthylphenylamine segment showed better device characteristics attributable to the higher HOMO energy level which probably facilitates the regeneration of the dye and effective suppression of the back reaction of the injected electrons with the I-3(-) in the electrolyte. The optical properties of the dyes were modeled using TDDFT simulations employing different theoretical models (B3LYP, CAM-B3LYP, and MPW1K), and the best correlations with the observed parameters have been found for CAM-B3LYP and MPW1K calculations. The electron lifetimes extracted from the electrochemical impedance measurements of the dye-sensitized solar cells were used to interpret the solar cell efficiency alternations.