Thin Solid Films, Vol.592, 14-23, 2015
Effects of rubrene co-sensitized TiO2 photoanode on the performance of ruthenium dye N719 sensitized solar cells
A notable organic semiconductor of rubrene with better charge-transport property and wide adsorption spectra is firstly employed as a co-adsorbent into N719 sensitized dye sensitized solar cells (DSSCs). After co-sensitized the TiO2 photoanode with rubrene, a short circuit current density (J(sc)) of 18.69 mA cm(-2), an open circuit voltage (V-oc) of 0.73 V and a fill factor (FF) of 0.56 corresponding to an overall conversion efficiency (eta) of 7.64% under AM 1.5 G solar irradiation are achieved, which is 40% higher than that for DSSCs without rubrene (eta = 5.46%, J(sc) = 14.29 mA cm(-2), V-oc = 0.67 V, and FF = 0.57) under the same condition. The higher eta value of co-sensitized solar cells is attributed to the enhanced photovoltaic parameters J(sc) and V-oc. The combined light harvesting of N719 and rubrene in the region of 300-750 nm and the better charge-transport property of rubrene which promote the electron transfer together lead to the high J(sc), while V-oc is enhanced owing to the retarded charge recombination and the prolonged electron lifetime due to the formation of a compact molecular layer composed of rubrene and N719 molecular. Mechanistic investigations are carried out by various electrochemical and spectral characterizations. (C) 2015 Elsevier B.V. All rights reserved.