Importance of Bi-O Bonds at the CsAgBiBr Double-Perovskite/Substrate Interface for Crystal Quality and Photoelectric Performance.

Interface interactions between perovskite materials and substrates are of great significance for the development of high-quality perovskite materials. Herein, we have successfully prepared CsAgBiBr double-perovskite films via a one-step spin-coating process and demonstrated a novel approach that modifies the surface of substrates with an ultrathin metal oxide (MO) layer to promote the film quality and photoelectric performance. Characterization results strongly suggest that the improvement is attributed to the Bi-O interfacial interaction at substrate/perovskite interface.