Metal halide perovskite material is one of the most promising materials for next-generation optoelectronic devices. In particular, the performance of perovskite solar cells and light emitting diodes is already rivaling or surpassing that of commercialized devices. However, there are critical obstacles to overcome for commercialization of the perovskite optoelectronics such as poor stability and scalability. Our group studies fundamental material science and device physics to resolve these issues.