在本文中,我们对12种D-A-π-A型有机染料(G-1〜G-3,M-1〜M-3,J-1〜J-3和S-1〜S-3)进行了理论研究。以9-苯基咔唑为电子供体,以预期这些染料在染料敏化太阳能电池(DSSC)中的应用。DFT和TD-DFT方法用于详细研究分子几何形状,前沿分子轨道(FMO),吸收光谱,电荷密度差(CDD),和几种染料的转移密度矩阵(TDM)。结果表明,M系列(M-1~M-3)染料在电子给体和辅助受体之间具有最大的二面角,在HOMO-LUMO轨道上也具有最大的能隙,大大降低了电荷转移效率。最后,UV-Vis吸收光谱推断,邻硝基苯甲酸修饰的锚定基团(G-3,M-3,J-3,S-3)可以使染料的吸收峰发生红移,这导致更高的光捕获效率并提高DSSC的功率转换效率。总的来说,所有这些染料都有助于提高光伏功率转换效率,并具有在DSSCs器件中应用的潜力。
In this paper, we performed theoretical studies on the twelve D-A-π-A type organic dyes (G-1 ~ G-3, M-1 ~ M-3, J-1 ~ J-3, and S-1 ~ S-3) with 9-phenylcarbazole as the electron donor in anticipation of the application of these dyes in dye-sensitized solar cells (DSSCs). DFT and TD-DFT methods are applied to investigate in detail the molecular geometries, frontier molecular orbitals (FMOs), absorption spectra, charge density difference (CDD), and transition density matrix (TDM) of several dyes. The results show that the M-series (M-1 ~ M-3) dyes have the largest dihedral angles between the electron donor and the auxiliary acceptor and also has the largest energy gaps in HOMO-LUMO orbitals, which greatly reduces the charge transfer efficiency. Finally, the UV-Vis absorption spectra inferred that the anchoring groups modified with o-nitrobenzoic acid (G-3, M-3, J-3, S-3) can red-shift the absorption peaks of the dyes, which results in higher light-harvesting efficiency and improves the power conversion efficiency of DSSCs. Overall, all of these dyes contribute to the improvement of photovoltaic power conversion efficiency and have potential for application in DSSCs devices.