Year: 2026
Type: article
Abstract: BackgroundPerovskite film fabrication techniques have a significant impact on film quality and device performance. While in situ synchrotron-based Grazing-Incidence Wide Angle X-ray Scattering (GIWAXS) has made significant progress in solution-processed perovskite films, the study of vacuum evaporation techniques still lacks a dedicated in situ characterization system.PurposeThis study aims to investigate the crystallization process of dual-source co-evaporated CsPbI2Br perovskite films using in situ GIWAXS.MethodsFirstly, a customized dual-source co-evaporation vacuum system was developed for in situ GIWAXS experiments at synchrotron beamlines with vacuum level (6.7×10-7 Pa), motion precision (5 μm) and angular precision (0.01°). Then, this system was installed at the X-ray diffraction beamline of Shanghai Synchrotron Radiation Facility (SSRF) to investigate the CsPbI2Br perovskite film during its deposition at substrate temperatures of 25 ℃ or 85 ℃ followed by the annealing process. Finally, the fabricated films were characterized using in situ X-ray Photoelectron Spectroscopy (XPS) and Ultraviolet Photoelectron Spectroscopy (UPS) after the evaporation vacuum system interconnected with the photoemission vacuum system for analyzing their electronic structures.ResultsThe GIWAXS measurements results reveal that preheating the substrate to 85 ℃ facilitated the formation of highly crystallized PbI2 during deposition, with its diffraction intensity approximately twice that of the perovskite black-phase. After deposition on substrates at 85 ℃, an annealing at 380 ℃ successfully converts intermediate phases into pure black-phase CsPbI2Br with high preferential orientations. The perovskite films deposited on substrates at 85 ℃ show significantly enhanced perovskite diffraction peak intensity compared to those on substrates at 25 ℃.ConclusionsThe dual-source co-evaporation system developed in this study enables comprehensive in situ GIWAXS study of CsPbI2Br crystallization dynamics. Results of this study provide important guidance for optimizing the evaporation deposition process of large-area perovskite films for photovoltaic applications.
Source: Nuclear Techniques
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7128788113