CH3NH3CdCl3: A promising new lead‐free hybrid organic–inorganic perovskite for photovoltaic applications

Abstract In the last few years, new photovoltaic compounds have been sought out for the conversion of renewable and clean solar energy with a view to reducing the production cost of electricity and enhancing the conversion efficiency with a simple manufacturing process. Hybrid organic–inorganic perovskites have emerged among the most promising materials with potential applications in the optoelectronic and photovoltaic fields. These photovoltaic materials draw such a great deal of attention that they are marching towards commercialization thanks to their excellent optical properties, high-power conversion efficiency and low-processing cost. In this paper, we introduce the optical properties of a new lead-free perovskite CH3NH3CdCl3 (MACdCl3) which adopts a tetragonal symmetry (space group P4mm) at ambient conditions. Optical measurements proved that this highly crystalline perovskite absorber has a broad and total visible to near-infrared absorption as well as a tunable indirect band gap (1.1 eV). Besides, recent studies have proposed that the indirect gap is due to the Rashba spin–orbit coupling. These excellent results definitely present a path to high-power conversion efficiency in a two-junction device such as the perovskite-perovskite tandem solar cells.