Improving power conversion efficiency by Light-Assisted annealing of triple cation perovskite layer in solar cell applications

Here we propose a light-assisted annealing (LA) method, for the formation of relatively larger and uniform grains of triple perovskite crystals with less nano-cracks in a custom designed LA system with a 250 mW/cm(2) halogen lamb. This method has the potential to reduce the annealing process time and energy consumption for mass production of perovskite solar cells (PSCs). For this purpose, initially, a series of perovskite films are prepared by LA method with various annealing time (1, 3, 5, 10, 15 min) to determine the optimum conditions. Subsequently, a comparative study is carried out for morphology, crystal structure and optic characterization. To assess the effect of the LA process on the structure and morphology of perovskite crystals, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and UV-Vis absorption spectroscopy techniques are carried out. Consequently, the photovoltaic application and stability tests are carried out with LA and TA films. A power conversion efficiency (PCE) of 17.86 % is achieved with an LA device annealed for 5 min (5-min-LA),while that of 16.74% is obtained with the standard device annealed on a hotplate for 60 min (60-min-TA).