Significantly improved performance of dye-sensitized solar cells by optimizing organic dyes with pyrrole as the isolation spacer and utilizing alkyl chain engineering

Abstract

The optimization of interfacial and intramolecular charge transfer of organic dyes is crucial to the photovoltaic performance of dye-sensitized solar cells. In this study, an efficient strategy was afforded by the introduction of alkylated pyrrole as the isolation spacer into organic dyes. The interfacial charge transfer can be organized by the tunable alkyl chains as a barrier layer to inhibit electron recombination, and the pull–push system can be strengthened by the incorporation of electron-withdrawing units (benzothiadiazole) and electron-rich moieties (pyrrole) into the conjugated bridge simultaneously, resulting in excellent light-harvesting capability. Therefore, the high conversion efficiency of 9.70% was achieved by LI-124 with suitable alkyl chains and device optimization.