First application of the HETPHEN concept to new heteroleptic bis(diimine) copper(i) complexes as sensitizers in dye sensitized solar cells
作者:Martina Sandroni、Megumi Kayanuma、Aurélien Planchat、Nadine Szuwarski、Errol Blart、Yann Pellegrin、Chantal Daniel、Mohammed Boujtita、Fabrice Odobel
DOI:10.1039/c3dt50852h
日期:——
We report here the synthesis and full chemical and physical characterizations of the first stable heteroleptic copper(I)-bis(diimine) complexes designed for implementation in dye sensitized solar cells (DSC). Thanks to the HETPHEN concept, pure and stable heteroleptic copper(I) complexes were isolated. Anchorage of the sensitizers was provided by 2,2′-biquinoline-4,4′-dicarboxylic acid (dcbqH2), while sterically challenged ligands 2,9-dimesityl-1,10-phenanthroline (L0) and N-hexyl-2,9-dimesityl-1,10-phenanthroline-[a:b]imidazo-(4′-dianisylaminophenyl) (L1) were used to complete the copper(I) coordination sphere. The resulting heteroleptic complexes C1 and C2 exhibit a broad MLCT transition spreading over a wide wavelength domain, especially when adsorbed onto nanoparticulate TiO2 photoanodes, providing a rather comprehensive visible light collection. The corresponding DSC were evaluated under AM 1.5 simulated solar light and rather weak performances were obtained owing to small Jsc and Voc. This is due to a combination of low extinction coefficient and poor driving forces for the various interfacial processes. However, significant improvements in the performances were monitored upon ageing in the dark, likely due to beneficial reorganization of the dye monolayers. The possibility to isolate stable asymmetric systems paves the way for structurally assisted photo-induced charge injection from the chemisorbed copper(I) based sensitizers into the conduction band of TiO2, through charge vectorialization.
我们在此报告了首个稳定的异配位铜(I)-双亚胺络合物的合成及其全面的化学和物理特性表征,这些络合物旨在用于染料敏感太阳能电池(DSC)。得益于HETPHEN概念,纯净且稳定的异配位铜(I)络合物被分离出来。感光剂的锚定由2,2′-双喹啉-4,4′-二羧酸(dcbqH2)提供,而立体位阻挑战性配体2,9-双美克烯基-1,10-菲咯烯(L0)和N-己基-2,9-双美克烯基-1,10-菲咯烯-[a:b]咪唑-(4′-二乙氧基氨基苯)(L1)被用来完成铜(I)的配位球。得到的异配位络合物C1和C2表现出广泛的金属-配体电荷转移(MLCT)跃迁,尤其是当其吸附在纳米颗粒TiO2光阳极上时,提供了相当全面的可见光收集。相应的DSC在AM 1.5模拟太阳光下进行评估,但由于小的短路电流密度(Jsc)和开路电压(Voc),性能相对较弱。这是由于低消光系数和各种界面过程的驱动力不足的共同作用。然而,经过在黑暗中老化后,性能有了显著改善,这可能是由于染料单层的有益重组。稳定的非对称体系的分离为实现结构辅助的光激励电荷注入铺平了道路,使从化学吸附的基于铜(I)的感光剂向TiO2导带的电荷向量化成为可能。