Perovskite solar cells based on a perovskite film with improved film coverage

Organic-inorganic halide perovskite solar cells have attracted considerable attention because of its high efficiency, low-cost fabrication, and flexibility. The film morphology has to be well controlled since the presence of pinholes in the perovskite films deteriorates the performance of the devices. Therefore, a variety of methods have been developed to realize high quality perovskite films and excellent device performance. In this work, hot-casting technique and additive engineering were investigated for obtaining a better film morphology. Optical microscopy, electron scanning microscopy and X-ray diffraction were used to monitor the morphology and the crystallinity of the perovskite films. We found that pinhole-free perovskite films cannot be obtained by the hot-casting technique alone. By using the hot-casting technique and incorporating the additive in the perovskite precursor, perovskite films with minimum pinholes were obtained when optimum hot-casting temperature and the amount of the additive were used. A reproducible average power conversion efficiency of 9.24 % was observed. The findings showed that the perovskite films depend not only on the usage of hot-casting technique but also through the incorporation of additives which can be used for other perovskite materials utilizing as solar cells.