Solution Processed Solar Cells

Photovoltaics have experienced a rapid development in the device structure, material process and efficiency in the past decade. Here, uniform, fully converted CH3NH3PbI3 films were synthesized at room temperature by converting PbI2 in a saturated solution of CH3NH3I in 2-propanol/hexane (cyclohexane). Solar cells with a structure of ITO/ZnO/CH3NH3PbI3/graphite/carbon black electrode were fabricated by spin coating at ambient conditions. The best device yielded 10.2% power conversion efficiency. PbI2-based photovoltaic devices having ITO/ZnO (or WO3) /PbI2/graphite (or without graphite) /carbon black structure were fabricated by spin coating at ambient conditions. The best devices yielded 0.32% power conversion efficiency. Pure 2H CuFeO2 nanoplates with a thickness of about 100 nm were synthesized at temperatures as low as 100 °C. 2H CuFeO2 has a band gap of 1.33 eV, high absorption coefficient, and highly photostability. The material appears promising for solar applications. A new method based on the cation exchange reaction for the synthesis of CuxZnySn2-0.25x-0.5yS4 with the crystallite size more than 85 nm was developed. This method appears promising for facilitating the development of Cu2ZnSnS4 based devices.