Metal to Halide Perovskite (HaP): An Alternative Route to HaP Coating, Directly from Pb⁽⁰⁾ or Sn⁽⁰⁾ Films

Halide perovskite film-based devices (e.g., solar cells and LEDs) have shown unique device performance. These films are commonly prepared from toxic solutions of metal salts (e.g., Pb²⁺ in DMF or DMSO). We describe a method to form halide perovskite films by simply reacting metal (Pb or Sn) films with alcoholic solutions of monovalent alkali metal or alkyl ammonium halides, which avoids the use of toxic Pb²⁺ solutions in the manufacturing step. We show how the morphology of the films can be controlled by variation in reaction parameters and also how mixed halide perovskite films can be prepared. A mechanism for the metal-to-perovskite conversion is suggested. We further show how electrochemically assisted conversion can allow control over the oxidation state of the metal and increase the reaction rate greatly.