Porphyrins with intense absorptivity: highly efficient sensitizers with a photovoltaic efficiency of up to 10.7% without a cosensitizer and a coabsorbate

Abstract

It is significantly challenging to collect more light and simultaneously avoid dye aggregation in dye-sensitized solar cells (DSSCs). This work addresses the significance of the intensity, rather than just the traditionally emphasized broadness, of the absorption band in developing DSSC sensitizers. With the assistance of calculating the oscillator strength of the first transition, the indoline-conjugated porphyrin sensitizer CM-b is screened out to have an impressively large Q_x molar absorptivity and thus an improved light harvesting ability together with suppressed aggregation in DSSCs. As a result, an overall efficiency of 10.7% for iodine-based DSSCs is achieved, which is a record for non-ruthenium iodine-based DSSCs in the absence of a cosensitizer and a coabsorbate.