Enhancing Crystallinity of Perovskite Materials through Rapid Microwave Annealing

With their unique crystal structure and relatively simple processing, perovskite solar cells have great potential for cost-effective clean energy. This work explores the use of microwave annealing as a fast and efficient processing technique to improve the quality of the perovskite films and overcome some of the main limitations of the traditional hot plate heating method upon scaling up. In this work, MAPbI3 and CsFA-based triple halide perovskite samples were prepared onto FTO glass substrates and treated under different conditions of microwave power and processing durations. Scanning electron microscopy showed that the microwave-annealed samples illustrated larger grains than hotplate annealing in a shorter time. Such fast growth of larger crystals is favorable for high-quality perovskites since it could reduce recombination pathways and enhance carrier transport. At higher microwave powers, however, partial detachment of the film occurred around the edges of the film due to localized heating because of the deflections of microwaves on the edges of the FTO layer. Again, this was in agreement with COMSOL Multiphysics simulations. Our work demonstrates the opportunities of microwave annealing in fast and efficient preparation of highquality perovskite films while at the same time pointing out the challenges that have to be met in superior implementation. The study contributes to developing effective methodologies for preparing high-quality perovskite materials for scalable, high-performance solar cell manufacturing.