ABSTRACT Six p-type dyes with D-π-A structures were designed, and their molecular structures and electronic properties were studied by the density functional theory and the time-dependent density functional theory. Thiophene, thiophene[3,4-c][1,2,5] thiadiazide and thiazole[5,4-d]thiazole in combination with dithieno[3,2-b:2',3'-d]thiophene (s-DTT) were introduced into the newly designed dyes to extend π-linkers. The results showed that the enhanced conjugation of π-linkers increases the coplanarity and decreases HOMO–LUMO gap of the dyes. The absorption spectra of dyes 1–6 are obviously red-shifted. Compared to those of QT-1, the spectra of dyes 3 and 6 are red-shifted by 128 and 154 nm, and the oscillator strengths are improved by 70% and 71%, respectively. Dyes 3 and 6 have not only the strongest absorption peaks, but also a large absorption area in the range of 400–900 nm. This guarantees them stronger light absorptions. They also have the maximum charge separation degree (t), resulting a reduced hole recombination. Furthermore, the light harvesting efficiency (LHE), hole injection power (ΔGinj), dye renewable power (ΔGreg) and charge recombination force (ΔGCR) of dyes 3 and 6 are superior to those of other dyes. In addition, the bromine substitution can effectively promote the red-shift of the absorption spectra.

中文翻译：

---

π-接头对三芳胺基p型D-π-A敏化剂影响的理论研究

摘要 设计了 ​​6 种具有 D-π-A 结构的 p 型染料，并利用密度泛函理论和瞬态密度泛函理论研究了它们的分子结构和电子性质。噻吩、噻吩[3,4-c][1,2,5]噻二嗪和噻唑[5,4-d]噻唑与二噻吩并[3,2-b:2',3'-d]噻吩（s -DTT) 被引入到新设计的染料中以扩展 π-接头。结果表明，π-接头的增强共轭增加了染料的共面性并降低了 HOMO-LUMO 间隙。染料 1-6 的吸收光谱明显红移。与QT-1相比，染料3和6的光谱红移了128和154 nm，振子强度分别提高了70%和71%。染料 3 和 6 不仅具有最强的吸收峰，而且在 400-900 nm 范围内有很大的吸收区域。这保证了它们更强的光吸收。它们还具有最大的电荷分离度 (t)，从而减少了空穴复合。此外，染料 3 和 6 的光捕获效率（LHE）、空穴注入功率（ΔGinj）、染料可再生功率（ΔGreg）和电荷复合力（ΔGCR）均优于其他染料。此外，溴取代可以有效地促进吸收光谱的红移。染料 3 和 6 的染料再生能力（ΔGreg）和电荷复合力（ΔGCR）均优于其他染料。此外，溴取代可以有效地促进吸收光谱的红移。染料 3 和 6 的染料再生能力（ΔGreg）和电荷复合力（ΔGCR）均优于其他染料。此外，溴取代可以有效地促进吸收光谱的红移。