Magnetron Sputtering Deposition of High Quality Cs 3 Bi 2 I 9 Perovskite Thin Films

• Published in: Materials Vol. 16; no. 15
• Main Authors: Caporali, Stefano, Martinuzzi, Stefano Mauro, Gabellini, Lapo, Calisi, Nicola
• Format: Journal Article
• Language: English
• Published: Switzerland 27.07.2023
• Subjects: perovskite; temperature; magnetron sputtering; lead-free; Cs3BI2I9
• ISSN: 1996-1944; 1996-1944

Nontoxic all-inorganic perovskites are among the most promising materials for the realization of optoelectronic devices. Here, we present an innovative way to deposit lead-free, totally inorganic Cs Bi I perovskite from vapor phase. Taking use of a magnetron sputtering system equipped with a radiofrequency working mode power supply and a single target containing the correct ratio of CsI and BiI salts, it was possible to deposit a Cs Bi I perovskitic film on silicon and soda-lime glass. The target composition was optimized to obtain a stoichiometric deposition, and the best compromise was found with a mix enriched with 20% / of CsI. Secondly, the effect of post-deposition thermal treatments (150 °C and 300 °C) and of the deposition on a preheat substrate (150 °C) were evaluated by analyzing the chemical composition, the morphology, the crystal structure, and the optical properties. The thermal treatment at 150 °C improved the uniformity of the perovskite film; the one at 300 °C damaged the perovskite deposited. Depositing on a preheated substrate at 150 °C, the obtained film showed a higher crystallinity. An additional thermal treatment at 150 °C on the film deposed on the preheated substrate showed that the crystallinity remains high, and the morphology becomes more uniform.