Interstitial Rare-Earth Doping of FAPbI₃ Perovskite Nanocrystals under Mild Ambient Conditions

However, prior approaches to synthesizing RE-doped perovskite nanocrystals (PNCs) have predominantly required harsh synthesis conditions, including an inert gas atmosphere and high temperatures. Here, we present a doping strategy using four RE ions (La³⁺, Nd³⁺, Gd³⁺, and Er³⁺) doped into FAPbI₃ PNCs under mild conditions (50 °C) in an ambient atmosphere.

Density functional theory calculations were performed to rationalize the RE incorporation by evaluating the formation energy of possible dopant configurations within the FAPbI₃ lattice. The results demonstrated that RE ions were successfully introduced into interstitial sites in the FAPbI₃ lattice under mild conditions. RE-doped FAPbI₃ PNCs were demonstrated to preserve the structure of α-FAPbI₃ PNCs, while improving the optical properties in colloidal and thin-film samples, delivering an enhanced power conversion efficiency of 18.65% in photovoltaic performance together with improved stability relative to pristine PNCs.