College of Materials Science and Engineering, Wuhan Textile University, 430073 Wuhan, China.
Chemphyschem. 2012 Oct 8;13(14):3320-9. doi: 10.1002/cphc.201200273. Epub 2012 Jul 4.
A series of metal-free organic donor-π bridge-acceptor dyes are studied computationally using density functional theory (DFT) and time-dependent DFT (TDDFT) approaches to explore their potential performances in dye-sensitized solar cells (DSSCs). Taking triphenylamine (TPA) and cyanoacrylic acid moieties as donor and acceptor units, respectively, the effects of different substituents of the π linkers in the TPA-based dyes on the energy conversion efficiency of the DSSCs are theoretically evaluated through optimized geometries, charge distributions, electronic structures, simulated absorption spectra, and free energies of injection. The results show that the molecular orbital energy levels and electron-injection driving forces of the TPA dyes can be tuned by the introduction of substituents with different electron-withdrawing or -donating abilities. The electron-withdrawing substituent always lowers the energies of both frontier orbitals, while the electron-donating one heightens them simultaneously. The efficiency trend of these TPA derivatives as sensitizers in DSSCs is also predicted by analyzing the light-harvesting efficiencies and the free energies of injection. The following substituents are shown to increase the efficiency of the dye: OMe, OEt, OHe, and OH.
一系列无金属有机给体-π 桥-受体染料通过使用密度泛函理论（DFT）和时间相关的密度泛函理论（TDDFT）方法进行了计算研究，以探索它们在染料敏化太阳能电池（DSSC）中的潜在性能。以三苯胺（TPA）和氰基丙烯酸酯部分分别作为供体和受体单元，通过优化几何形状、电荷分布、电子结构、模拟吸收光谱和注入自由能，理论评估了 TPA 基染料中π 连接体的不同取代基对 DSSC 能量转换效率的影响。结果表明，通过引入具有不同吸电子或供电子能力的取代基，可以调节 TPA 染料的分子轨道能级和电子注入驱动力。吸电子取代基总是降低前线轨道的能量，而供电子取代基则同时升高它们的能量。通过分析这些 TPA 衍生物作为 DSSC 敏化剂的光捕获效率和注入自由能，预测了它们的效率趋势。结果表明，OMe、OEt、OHe 和 OH 等取代基可以提高染料的效率。
