Co-Sensitization By Triarylamine Dyes For Improved Dye-Sensitized Solar Cells

To improve the performance of solar cells, two previous triarylamine dyes with different planarities reported by us, AFL2 and AFL3, were combined with dye D1 as a cosensitizer and tested for the co-sensitization of dye-sensitized solar cells (DSSCs) without using Al2O3-coated TiO2. The photophysical and photovoltaic performance as well as the electrochemical properties of the co-sensitized DSSCs were investigated. The results suggested an enhancement of the efficiency, which was in accordance with the increase in molar ratio of AFL2 and the decrease of AFL3. Other data revealed that lower molar ratios of AFL2/D1 did not only compensate for the peak-valley of IPCE near 400nm but also delayed charge recombination, and that AFL3/D1 at lower molar ratios could lead to dye aggregation. The photovoltaic efficiencies of the resulting AFL2 and AFL3 increased from 4.83% and 5.81-5.87% (ratio of 1:1) and 6.44% (ratio of 4:1), corresponding to 20 and 11% improvement, respectively. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim