High-Speed Vapor Transport Deposition of Perovskite Thin-Films.

Intensive research of hybrid metal-halide perovskite materials for use as photoactive materials has resulted in an unmatched increase in the power conversion efficiency of perovskite photovoltaics (PVs) over the last couple of years. Now that lab fabricated perovskite devices rival the efficiency of silicon PVs, the next challenge of scalable mass manufacturing of large perovskite PV panels remains to be solved. For that purpose, it is still unclear which manufacturing method will provide the lowest processing cost and highest quality solar cells. Vapor deposition has been proven to work well for perovskites as a controllable and repeatable thin-film deposition technique, but with processing speeds currently too slow to adequately lower the production costs. Addressing this challenge, in the present work we demonstrate a high-speed vapor transport processing technique in a custom-built reactor that produces high quality perovskite films with unprecedented deposition speed exceeding 1 nm/s, over 10x faster than previous vapor deposition demonstrations. We show that the semiconducting perovskite films produced with this method have excellent crystallinity and opto-electronic properties with 10 ns charge carrier lifetime, enabling us to fabricate the first photovoltaic devices made by perovskite vapor transport deposition. Our experiments are guided by computational fluid dynamics simulations that also predict that this technique could lead to deposition rates on the order of micrometers per second. This, in turn, could enable cost-effective scalable manufacturing of the perovskite-based solar technologies.