Imine-carbene-based ruthenium complexes for dye-sensitized solar cells: The effect of isomeric mixture on the photovoltaic performance

New isomeric sensitizers containing an imine-carbene (IC)-based ancillary ligand, isomers IC101 and IC102, were designed for application in dye-sensitized solar cells (DSSCs). These ruthenium complexes were synthesized and isolated using simple purification methods. The DSSCs sensitized with IC101 and IC102 exhibited overall conversion efficiencies of 6.32% and 6.59%, respectively. Although these two isomers gave similar device output, reduction in the power conversion efficiency (5.52%) was observed when the cell was fabricated using a 1:1 mixture of both sensitizers. The results highlight the importance of isomeric purity of the sensitizing complexes to gain high performance DSSCs.