Effect of Deuteration on Morphology of 2D Perovskite (CH3NH3)2Pb(SCN)2I2

Abstract

The newly emerged family of organic-inorganic halide perovskites not only revolutionizes the field of photovoltaic research with an average PCE > 20%; but also triggers plentiful studies on optical gain, light-emitting diodes, and field-field-transistors due to the tunability of optical and electrical properties brought by the versatility of organic chemistry synthesis. Most of the works focus on achieving a higher power conversion efficiency and/or light-emitting properties through a variety of chemical synthesis, novel growth conditions, and fabrication methods [1,2]. The solution-processed three-dimensional (3D) organic-inorganic halide perovskites have shown great promise as solar cells [1] due to high charge carrier mobility, long exciton diffusion length, and low concentration of traps, but their poor stability over longer periods of time due to heat, moisture, light, etc. has stopped them from becoming widely commercialized. However, two-dimensional perovskites (2D) have emerged as a replacement for the 3D perovskites, offering superior properties such as longer lifetime, more stability, higher bandgap, and versatility of organic chemistry synthesis [3][4][5][6][7]. However, the studies on the electronic structure and properties of 2D perovskite materials are very limited. Therefore, the investigation of optoelectronic properties in relation to chemical synthesis and morphological changes is critically important. In this work, we successfully synthesized deuterated methylammonium iodide (CH 3 ND 3 I) and prepared deuterated 2D perovskite (CH 3 ND 3 ) 2 Pb(SCN) 2 I 2 thin films and studied the impact of deuteration on morphological changes. X-ray diffraction (XRD) measurements were carried out for the structural characterization and scanning electron microscopy (SEM) was used for morphological characterization.