Carbazole–phenothiazine-based organic sensitizers via π-bridge functionalization with different electronegative/steric substituents: photophysical properties and DSSC performance

Four D–D–π–A carbazole-phenothiazine dyes bearing –H/–F/–OCH 3 /–Cl substituents on the phenyl π-bridge exhibit varied planarity and light-harvesting efficiencies. Dyes without electronegative groups show superior light harvesting, yielding higher PCE.