Modified colored semi-transparent perovskite solar cells with enhanced stability

Abstract

Long-term stability under external stimuli like humidity and heat is an important factor hindering real-world performance for perovskite solar cell. With the aim of high stability and wide band gap for semi-transparent solar cell application, layered bromide-based perovskites, (PEA)2MAn-1PbnBr3n+1 where n = 50, are our focus. Herein, we compared the additives such as polyethylene glycol (PEG), formamidinium iodide (FAI), and formamidinium bromide (FABr) and carefully determined underlying mechanisms. In addition to investigate their impacts on the perovskite structure under thermal stress and trap states, we tracked crystallite size and photovoltaic performance over time under humidity stimuli to determine materials progression and the impact on stability, identifying initial grain size enlarging and later defect formation. Additives had large impact on morphology and crystallinity over time, directly correlating to the progression of optoelectronic properties. FABr doping achieved relatively good power conversion for semi-transparent orange colored solar cells with the average visible transmittance of 26.12% along with good stability from stable perovskite cubic phase, showing high potential as materials for perovskite solar window application.