Solution-processed nanocrystalline TiO2 buffer layer used for improving the performance of organic photovoltaics.

In this study, we use solution-processable crystalline TiO(2) nanoparticles as a buffer layer between the active layer and aluminum cathode to fabricate the P3HT:PCBM-based bulk heterojunction (BHJ) organic photovoltaic (OPV) devices. The employment of the presynthesized TiO(2) nanoparticles simplifies the fabrication of OPV devices because of the elimination of an additional hydrolysis step of precursors in air. The fabricated OPV devices with the thermally stable TiO(2) buffer layer are subjected to the further postdeposition thermal annealing, resulting in a power conversion efficiency (PCE) as high as 3.94%. The improved device performance could be attributed to the electron transporting and hole blocking capabilities due to the introduced TiO(2) buffer layer.