Evaporation of Methylammonium Iodide in Thermal Deposition of MAPbI3

Abstract

Thermal evaporation is an important technique for fabricating methylammonium lead iodide (MAPbI3), but the process is complicated by the need to co-evaporate methylammonium iodide (MAI) and PbI2. In this work, the effect of water vapor during the thermal deposition of MAPbI3 was investigated under high vacuum. The evaporation process was monitored with a residual gas analyzer (RGA), and the film quality was examined with X-ray photoelectron spectroscopy (XPS). The investigations showed that during evaporation, MAI decomposed while PbI2 evaporated as a whole compound. It was found that the residual water vapor reacted with one of the MAI-dissociated products. The higher iodine ratio suggests that the real MAI flux was higher than the reading from the QCM. The XPS analysis demonstrated that the residual water vapor may alter the elemental ratios of C, N, and I in thermally deposited MAPbI3. Morphologic properties were investigated with atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). It was observed that a sample grown with high water vapor pressure had a roughened surface and poor film quality. Therefore, an evaporation environment with water vapor pressure below 10−8 Torr is needed to fabricate high quality perovskite films.

Advances and Perspectives of Titanium-Based Nanocomposites for Energy Generation and Environmental Remediation Applications: A Review

“…123 Thermal deposition is a mature technology that is widely accepted in semiconductor and coating industries because of its uniformity and chemical stoichiometry. 124 The application of thermal deposition for MAPbI3 (methylammonium lead iodide) synthesis exclusively for solar cells and mini-modules showed a remarkable record of efficiency of 18.13%. 125 Another study of ZnO nanosheets coated on g-C 3 N 4 films was conducted via thermal deposition to improve their photocatalytic activity.…”

Light-enhanced oxygen degradation of MAPbBr3 single crystal

“…[1][2][3] Among all perovskites, methylammonium lead halide (MAPbX 3 ) has outstanding optoelectronic properties, including long diffusion length, long carrier lifetime, a tunable bandgap, and a high absorption coefficient. [4][5][6][7][8][9][10] These characteristics not only contribute to its remarkable PCE but also expand its applications to light-emitting diodes, gas detectors, charged particle detectors and photodetectors. [11][12][13][14][15][16][17] In particular, MAPbBr 3 is considered superior to MAPbI 3 in some aspects, as it has higher hole mobility and is more stable than MAPbI 3 in air.…”

CuPc Passivation of a MAPbBr3 Single Crystal Surface

“…Organic–inorganic hybrid perovskites are considered to be ideal candidates for next generation solar cells as the power conversion efficiency of perovskite solar cells (PSCs) experienced a rapid development from 3.3% in 2009 to 25.7% in 2022. – Compared to its peers, methylammonium lead halide (MAPbX 3 ) exhibits excellent optical and electrical properties, including high absorption coefficient, high charge carrier mobility, long carrier lifetimes, low trap density, and high photoluminescence quantum yield, which result in a strong light-harvesting ability and high efficiency in light emission and detection. – These outstanding features of MAPbX 3 have broadened its potential applications to solid state lasers, light-emitting diodes, photodetectors, and gas detectors. – However, one of the biggest issues with this type of material is that it is vulnerable to almost all environmental factors such as heat, moisture, gas exposure, and light irradiation. – A lot of techniques have been applied to enhance the stability of perovskites including solvent engineering, additive engineering, and passivation engineering . In particular, passivation techniques can decrease the efficiency loss by effectively reducing charge carrier recombination and ion migration.…”