Inverted bulk-heterojunction organic solar cell using chemical bath deposited titanium oxide as electron collection layer

Chemical bath deposited titanium oxide (TiOx) as an electron collection layer is introduced between the organic layer and the indium tin oxide (ITO) electrode for improving the performance of inverted bulk-heterojunction organic thin film solar cells with 1 cm2 active area, where regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were mainly used as the photo-active layer. The uniform and thin TiOx film was easily prepared onto the ITO electrode in air by simple chemical bath deposition method. The cell performance was almost maintained in an ambient atmosphere under continuous light irradiation of 100 h despite non-sealing. The cell with bulk-heterojunction organic thin film consisted of [6.6] diphenyl C62 bis(butyric acid methyl ester) (bis-PCBM) and P3HT prepared under best condition showed the power conversion efficiency (PCE) of 3.8% under the AM1.5G simulated sunlight.