Design of new coumarin dyes having thiophene moieties for highly efficient organic-dye-sensitized solar cells

We have developed new coumarin dyes having thiophene moieties in order to improve the photovoltaic performance of dye-sensitized nanocrystalline TiO2 solar cells based on the organic dyes as photosensitizers. A solar-energy-to-electricity conversion efficiency (η) of 7.7% was attained under AM 1.5 irradiation (100 mW cm−2) with a short-circuit current density (Jsc) of 14.3 mA cm−2, an open-circuit voltage (Voc) of 0.73 V, and a fill factor (ff) of 0.74.