ADVANCES IN SOLUTION-SHEARED MAPbI3 THIN FILMS THROUGH MIXED-SOLVENT ENGINEERING

Abstract

The aim of this work is to produce perovskite semiconductor thin films with desirable photoactivity under high temperature deposition conditions by combining the solution shearing technique and solvent engineering. Currently, solution shearing is used to create perovskite solar cells by exploring low temperature solvents, and the wettability of the blade. Herein, this work reports on the role of solvent engineering in the crystallization process of solution sheared textured MAPbI3 films formed at higher than 150°C temperatures and in less than 2 minutes time. Dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), and 1-methyl-2-pyrrolidinone (NMP) are examined as well as their binary combinations to prepare solution-sheared crystalline methylammonium lead iodide (MAPbI3) perovskite films at temperatures higher than 150 °C, and close to the respective boiling points of the solvents. X-ray diffraction, grazing-incidence wide-angle X-ray scattering imaging, and photoluminescence (PL) were used as characterization methods to evaluate crystal size, quality, and ordering, and determine the viability of the films as optoelectronic devices. The main application explored is a perovskite solar cell, and the semiconductor’s stability within the device is tested. Excellent macroscopic crystals, over 1 mm in length, are achieved using a solvent mixture containing equal volumes of DMSO and NMP. These superior 3D MAPbI3 films retain their solvent–perovskite intermediate phases and exhibit high crystalline ordering, hence are essential for high-performing and stable optoelectronic devices.