High-performance formamidinium-based perovskite photodetectors fabricated via doctor-blading deposition in ambient condition

High-purity black alpha-phase formamidinium lead iodide (FAPbI(3), FA is NH2CH=NH+) perovskite poly-crystalline film was prepared using low-cost high-output doctor-blading deposition technique in ambient condition without further annealing process and any additives. The resulting alpha-phase FAPbI(3) perovskite has a large domain size over 200 mu m with (001) preferential crystallographic orientation. The photodetectors with an extremely simple structure were fabricated via doctor-blading, resulting in a responsivity as high as 11.46 AW(-1), a ratio of photocurrent/dark current (I-light/I-dark) as large as 10(5) and a response speed as fast as 5.4 ms. The results suggest that low-cost doctor-blading technique in ambient condition potentially pave a way to eliminate the yellow delta-phase FAPbI(3) and get a high-quality black alpha-FAPbl(3) perovskite film, as well as fabricate efficient FAPbI(3) perovskite optoelectronic devices. (C) 2017 Elsevier B.V. All rights reserved.