Influence of π-bridge in N-fluorenyl indoline sensitizers on the photovoltaic performance of dye-sensitized solar cells

Abstract Four N -fluorenyl indoline sensitizers were designed and synthesized to compare the influence of vinyl bond and aryl ring on the cell efficiency based on the cyanoacrylic acid acceptor. Compared with vinyl bond, the introduction of aryl ring enlarges the conjugation system of the whole molecule and brings out the improvement of the absorption spectra favoring the improvement of J SC . Among three kinds of aryl rings, benzene unit favors the photovoltage due to a reduction of electron recombination while the photocurrent more benefit from thiophene unit. Due to the best J SC , dye with thiophene π-bridge shows the most efficient photoelectricity conversion efficiency and has the maximum η value of 5.89% ( V OC  = 650 mV,  J SC  = 13.88 mA cm −2 , ff  = 0.71) under simulated AM 1.5 G irradiation (100 mW cm −2 ).