Gish Melissa K, Snell Katherine, Thorley Karl J, Anthony John E, Johnson Justin C
Materials, Chemistry and Computational Sciences Directorate, National Renewable Energy Laboratory, Golden, Colorado 80401, United States.
Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States.
J Phys Chem C Nanomater Interfaces. 2024 Aug 12;128(33):13944-13951. doi: 10.1021/acs.jpcc.4c04284. eCollection 2024 Aug 22.
Singlet fission, the process of transforming a singlet excited state into two lower energy triplet excited states, is a promising strategy for improving the efficiency of dye-sensitized solar cells. The difficulty in utilizing singlet fission molecules in this architecture is understanding and controlling the orientation of dyes on mesoporous metal oxide surfaces to maximize triplet production and minimize detrimental deactivation pathways, such as electron injection from the singlet or excimer formation. Here, we varied the concentration of loading solutions of two anthradithiophene dyes derivatized with either one or two carboxylic acid groups for binding to a metal oxide surface and studied their photophysics using ultrafast transient absorption spectroscopy. For the single carboxylic acid case, an increase in dye surface coverage led to an increase in apparent triplet excited-state growth via singlet fission, while the same increase in coverage with two carboxylic acids did not. This study represents a step toward controlling the interactions between molecules at mesoporous interfaces.
单线态裂变是将单线态激发态转化为两个能量较低的三线态激发态的过程，是提高染料敏化太阳能电池效率的一种很有前景的策略。在这种结构中利用单线态裂变分子的困难在于理解和控制染料在介孔金属氧化物表面的取向，以最大限度地产生三线态并最小化有害的失活途径，如单线态的电子注入或激基缔合物的形成。在这里，我们改变了两种分别带有一个或两个羧酸基团以结合到金属氧化物表面的蒽二噻吩染料负载溶液的浓度，并使用超快瞬态吸收光谱研究了它们的光物理性质。对于单羧酸的情况，染料表面覆盖率的增加导致通过单线态裂变产生的表观三线态激发态增长增加，而对于双羧酸，相同的覆盖率增加则没有这种效果。这项研究朝着控制介孔界面处分子间相互作用迈出了一步。
