A modified high-temperature vapour deposition technique for fabricating CH_3NH_3PbI_3 thin films under an ambient atmosphere

摘要

A modified two-step deposition technique was performed by vapour depositing methylammonium iodide (MAI) on lead iodide (PbI_2) films to fabricate good quality methylammonium lead iodide (MAPI) thin films under an ambient atmosphere, and their properties were compared with conventional two-step solution processed MAPI thin films. Scanning electron microscopy results depicted that the MAI vapour-processed films have a uniform coverage and planar surface compared with the non-uniformly distributed granule-like morphology of the solution-processed MAPI film. X-ray diffraction results confirm that the vapour-processed films have better crystallinity compared to the conventional solution-processed MAPI thin films. An enhancement in the optical absorption and emission was observed for the vapour-processed films. The higher processing temperature of the modified-vapour deposition eliminates the effect of moisture during the ambient atmosphere processing of the MAPI films.