Lead-free thermochromic perovskites with tunable transition temperatures for smart window applications

The structural flexibility of hybrid perovskite materials allows for phase transition and consequently thermochromic properties. Here we investigate the thermochromic performance in a series of copper-based layered perovskites with organic cations having different alky chain lengths. Their transition temperature is found to be dependent on the organic cations due to molecular motion and hydrogen bond interaction, providing possibilities to prepare thermochromic semiconductors near room temperature for smart window applications.