A novel approach towards compact and improved-crystallinity methylammonium bismuth iodide film via hot immersion method

Abstract

In this paper, we report the successful fabrication of compact and high crystallinity methylammonium bismuth iodide (MBI) layers by using a new method named as hot immersion method (HIM) for the first time. This novel method is proposed to improve the surface morphology and structural properties of MBI film. The substrate is dipped in the hot solution while the hot immersion time was varied. The scanning electron microscopy images showed that the compact MBI layer was fabricated at a longer immersion time, while the x-ray diffraction characterization showed that the crystallinity of the MBI layer was improved. The compactness and uniformity of MBI layer were further confirmed using Dektak measurement. Our findings suggest the enhanced performance of bismuth-perovskite solar cells (Bi-PeSC’s) device by the simple process in the future.