Consiglio Giuseppe, Gorczyński Adam, Spoto Guido, Petralia Salvatore, Forte Giuseppe
Department of Chemical Science University of Catania Via S. Sofia 64 95125 Italy
Faculty of Chemistry, Adam Mickiewicz University Uniwersytetu Poznańskiego 8 61-614 Poznań Poland.
RSC Adv. 2024 Aug 2;14(33):24185-24195. doi: 10.1039/d4ra05322b. eCollection 2024 Jul 26.
In this study, we designed squaraine-based dyes with a 2-amino pyrrole donor unit and acene groups like anthracene and pentacene. These dyes incorporate three different electron-withdrawing groups - cyanoacrylate (A1), phosphonate (A2) and boronic acid (A3) - as linkers to the TiO semiconductor. The spectroscopic, electronic and photochemical properties of these compounds were investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) simulations. Compared to the squarylium dye, SQD, the UV-vis data indicate excellent absorption especially for pentacene-based dyes, which extended beyond 920 nm, enhancing the panchromatic effect. The calculated excited-state lifetimes of these dyes were notably longer than SQD, particularly for those containing pentacene and either A1 or A2 withdrawing groups, with lifetimes approximately four times longer. In contrast, boronic acid derivatives had shorter excited-state lifetimes, hindering charge transfer. Simulations suggest all sensitizers can inject electrons into TiO and be efficiently regenerated by electron transfer from the electrolyte. The best results were achieved with pentacene and A1 or A2 as linkers, notably A1 dyes achieve superior short circuit photocurrent, , and power conversion efficiency, PCE, with over 50% improvement compared to SQD. Phosphonate derivatives exhibited the highest energy adsorption on TiO while still achieving significant open-circuit voltage, , , and PCE values. After surface adsorption, all dyes displayed efficient electron recovery, with HOMO levels significantly dropping below -4.8 eV. Our study demonstrates that computational design can significantly enhance experimental work, offering valuable insights to improve dye design and boost the performance of dye-sensitized solar cells.
在本研究中，我们设计了基于方酸菁的染料，其具有2-氨基吡咯供体单元以及蒽和并五苯等并苯基团。这些染料包含三种不同的吸电子基团——氰基丙烯酸酯（A1）、膦酸酯（A2）和硼酸（A3）——作为与TiO半导体的连接基。使用密度泛函理论（DFT）和含时密度泛函理论（TDDFT）模拟研究了这些化合物的光谱、电子和光化学性质。与方酸染料SQD相比，紫外可见光谱数据表明其具有优异的吸收性能，尤其是对于并五苯基染料，其吸收延伸至920 nm以上，增强了全色效应。这些染料计算得到的激发态寿命明显长于SQD，特别是对于那些含有并五苯以及A1或A2吸电子基团的染料，其寿命约为SQD的四倍。相比之下，硼酸衍生物的激发态寿命较短，阻碍了电荷转移。模拟表明所有敏化剂都可以将电子注入TiO，并通过电解质的电子转移有效地再生。以并五苯和A1或A2作为连接基时取得了最佳结果，特别是A1染料实现了优异的短路光电流和功率转换效率，与SQD相比提高了50%以上。膦酸酯衍生物在TiO上表现出最高的能量吸附，同时仍能实现显著的开路电压和功率转换效率值。表面吸附后，所有染料都表现出有效的电子恢复，其最高占据分子轨道（HOMO）能级显著下降至-4.8 eV以下。我们的研究表明，计算设计可以显著增强实验工作，为改进染料设计和提高染料敏化太阳能电池的性能提供有价值的见解。
