Coumarin-bearing triarylamine sensitizers with high molar extinction coefficient for dye-sensitized solar cells

Coumarin unit is introduced into triarylamine and three organic sensitizers are designed and synthesized with triarylamine bearing coumarin moiety as the electron donor, conjugated system containing thiophene unit as the it-bridge, and cyanoacetic acid moiety as the electron acceptor. The light-harvesting capabilities and photovoltaic performance of these dyes are investigated systematically with the comparison of different pi-bridges. High molar extinction coefficients are observed in these triarylamine dyes and the photocurrent and photovoltage are increased with the introduction of another thiophene or benzene. Optimal photovoltaic performance (eta = 6.24%, V-oc = 690 mV, J(sc) = 14.33 mA cm(-2), and ff = 0.63) is observed in the DSSC based on dye with thiophene-phenyl unit as the 7c-conjugated bridge under 100 mW cm(-2) simulated AM 1.5 G solar irradiation. (C) 2014 Elsevier B.V. All rights reserved.