Abstract
Organic–inorganic hybrid perovskite solar cells have the advantage of being able to implement a high conversion efficiency, easy fabrication process and low cost to commercial products of photovoltaic devices. The perovskite solar cells have a photovoltaic performance with reduced durability due to the volatility of organic cations and toxic lead in the perovskite crystal as an active layer. The purpose of this research is to investigate the effect of additives such as cupper chloride and potassium iodide in the perovskite crystal on the photovoltaic properties and electronic structure. The distribution of 3d orbital of cupper ion conjugated with 5p orbital of iodine ion at the valence band, and 6p orbital of lead ion at the conduction band, influences the charge generation and transfer, as well as the carrier mobility with a narrowing band gap. The addition of potassium iodide delocalizes the charge distribution near the cupper, iodide, and lead ions, which promotes the charge generation and carrier diffusion, yielding an increase in the short circuit current density relating to the conversion efficiency.