Hybrid solar cells based on poly(3-hexylthiophene) and electrospun TiO2 nanofibers with effective interface modification

Electrospinning, a low cost production method for large area nanofibrous films, is employed to fabricate organic-inorganic hybrid solar cells based on poly(3-hexylthiophene) and TiO2 nanofibers. The performance of the hybrid solar cells is optimized by modifying the surface of TiO2 nanofibers with ruthenium dye (N719) and 3-phenylpropionic acid, which results in the average power conversion efficiency of about 1.1% under AM 1.5G simulated illumination (100 mW cm−2). It is found that the co-modification of N719 and 3-phenylpropionic acid on TiO2 can induce more ordered backbone packing of poly(3-hexylthiophene) layer, lower density of trap states on the surface of TiO2 and longer lifetime of carriers in the active layer due to retarded recombination process by the modifier. Therefore the interface modification can dramatically enhance the photovoltaic performance.