Two new D-π-A-structured dyes (SGT-160 and SGT-161) with the extension of π-conjugation in the acceptor unit have been designed and synthesized to modulate LUMO energy levels and to investigate the photophysical and electrochemical properties as well as cell performances. Based on a reference dye of SGT-130 as a platform of donor-π-bridge-BTD-phenyl-acceptor sensitizers, ethynylphenylene (T-Ph) and 2-ethynylthiophene (T-Th) moieties as an auxiliary π-spacer were introduced to replace the traditional phenylene (Ph) moiety for SGT-160 and SGT-161, respectively. It was found that the insertion of an additional ethynyl moiety into the BTD-Ph acceptor unit significantly enhanced the light-harvesting capability by extending the absorption bands and intensifying the molar absorptivity. Moreover, the π-extension in the acceptor part was beneficial for stabilizing the LUMO energy levels. The density functional theory (DFT) calculations and the partial density of states (PDOS) suggest that the variation of acceptor units affects the electronic transition between the major orbitals of the dyes. As a result, dye-sensitized solar cells (DSSCs) based on SGT-160 with a chenodeoxycholic acid (CDCA) co-adsorbent exhibited high power conversion efficiencies (PCEs) of 10.28%, while DSSCs based on SGT-161 and SGT-130 showed moderate PCEs of 8.05% and 10.06%, respectively.

设计并合成了两种新的 D-π-A 结构染料（SGT-160 和 SGT-161），在受体单元中扩展了 π-共轭作用，以调节 LUMO 能级并研究光物理和电化学性质作为细胞表现。基于 SGT-130 参考染料作为供体-π-桥-BTD-苯基-受体敏化剂的平台，引入了乙炔基亚苯基（T-Ph）和 2-乙炔基噻吩（T-Th）部分作为辅助 π-间隔基分别取代 SGT-160 和 SGT-161 的传统亚苯基 (Ph) 部分。发现将额外的乙炔基部分插入 BTD-Ph 受体单元通过扩展吸收带和增强摩尔吸收率显着增强了光捕获能力。而且，受体部分的 π 延伸有利于稳定 LUMO 能级。密度泛函理论 (DFT) 计算和部分态密度 (PDOS) 表明受体单元的变化影响染料主要轨道之间的电子跃迁。因此，基于 SGT-160 和鹅去氧胆酸 (CDCA) 共吸附剂的染料敏化太阳能电池 (DSSCs) 表现出 10.28% 的高功率转换效率 (PCE)，而基于 SGT-161 和 SGT-130 的 DSSCs PCE 分别为 8.05% 和 10.06%。