The research of halide perovskite solar cells continues to boom with device energy conversion efficiency approaching that of single crystal silicon solar cells. Many unique properties have been discovered in halide perovskites, which may or may not explain the high efficiency in solution processed polycrystalline solar cells. I will present the advance in understanding the optoelectronic properties and electromechanical properties of halide perovskites. Our progress of material and device engineering of perovskite solar cells will also be presented and scaling up for commercialization will be briefed. The discovery of the extraordinary properties enables new application of halide perovskite in photodetectors, synapes, light emitting diodes, radiation detection beyond solar cells.