One-step method for the fabrication of high-quality perovskite thin-films under ambient conditions: Stability, morphological, optical, and electrical evaluation

Abstract

Stability is still a property that limits the commercialization of perovskite solar cells. Thus, with the development of continuous deposition methods, it is essential to determine their feasibility in terms of stability, and not only on the efficiency of the devices produced. In this work, a hot air blow-drying (HABD) method is proposed as an alternative for the deposition of CH3NH3PbI3 (MAPbI) perovskite thin-films. The ability of HABD to produce homogeneous and stable thin-films was systematically studied and compared with those produced with air at standard conditions (25 °C, 25% relative humidity). The MAPbI thin-films were characterized by infrared spectroscopy and X-ray diffraction revealing that air temperature rules the film hydration. Partial degradation after using air at standard conditions was observed in contrast with the stable and pure perovskite phase obtained when using air heated at 90 C°. The influence of solution concentration on the surface coverage was determined by scanning electron and atomic force microscopies. It was found that 4 µL of precursors solution (0.434 M) produced a homogeneous MAPbI thin-film with ~180 nm thickness and roughness of (Rq ~ 29 nm) covering a 6.25 cm2 area. Moreover, the outstanding optical and electrical properties of MAPbI were not affected by the deposition procedure. Remarkably, degradation tests demonstrate that our HABD method is capable of producing stable MAPbI thin-films with excellent resistance to degradation at ambient conditions (up to 15 days), which makes it a promising low-cost and easy to use method for the continuous fabrication of perovskite solar cells.