Benzo[1,2-b:4,5-b ']dithiophene and benzo[1,2-b:4,5-b ']difuran based organic dipolar compounds for sensitized solar cells

摘要

Novel organic dyes that consist of either a benzo[1,2-b:4,5-b']dithiophene or a benzo[1,2-b:4,5-b']difuran core exhibited remarkable solar-to-energy conversion efficiency in dye-sensitized solar cells. The planar geometry of bridge moiety and its bulky substituents helped the dyes to form a high quality monolayer on the surface of titanium oxide. A typical device displayed photon-to-current conversion efficiency 60% in the region of 380-575 nm, a short-circuit photocurrent density 13.45 mA cm(-2), an open-circuit photovoltage 0.72 V, and a fill factor 0.63, corresponding to an overall conversion efficiency 6.12%. In a test of using deoxycholic acid as a co-absorbent, an improvement of quantum efficiencies 8.37% was observed for certain compounds. However, for others the quantum efficiency decreased in 6.60-7.91%. The latter result indicated that the quality of some films cannot be further improved by the addition of deoxycholic acid. The photophysical properties were analyzed with the aid of TDDFT. (C) 2014 Elsevier Ltd. All rights reserved.