Inverted polymer solar cells with TiO2 electron extraction layers prepared by magnetron sputtering

TiO2 thin films deposited by magnetron sputtering possess excellent optical transmittance, high refractive index, good adhesion and chemical stability. In this manuscript, TiO2 thin films deposited by magnetron sputtering was used for the first time as an electron extraction layer in inverted polymer solar cells (IPSCs), and the effect of the TiO2 thickness on the photovoltaic performance of P3HT:PC61BM IPSCs was investigated. The highest PCE value of 3.75% was obtained when the thickness of TiO2 thin films was in the range between 42 nm and 73 nm. The absorption properties, morphology and structure of the TiO2 films were characterized by UV-Vis spectroscopy, SEM and Raman spectroscopy, and were related to the device performance of P3HT:PC61BM IPSCs. The results indicate that TiO2 films deposited by magnetron sputtering are an excellent electron extraction layer for IPSCs.