C1s xps peak table
A sequential deposition method was then developed to control the morphology of the perovskite films, which led to a better device performance and repeatability 10. Initially, the perovskite films in mesoscopic PSCs were made using a precursor by a one-step deposition method 13, which led to an unstable film morphology and large variations in the cell efficiency. These perovskite solar cells (PSCs) could be fabricated as mesoscopic or planar structured devices 7, 8, 9, 10, 11, 12. CH 3NH 3PbI 3 perovskite has diverse advantages, such as a high absorption coefficient, an ideal band gap energy of ~1.5 eV, high carrier mobility, and a defect tolerance 2, 3, 4, 5, 6. Lead-based organic–inorganic hybrid perovskites have recently attracted much attention as superior light-harvesting materials and offer high power conversion efficiencies of >25% for certified cells 1. The discovery of the X-ray-induced chemical state change and the volatile methylamine of perovskite crystals could be further applied as an indicator for the field of X-ray sensors or detectors. In addition, the nitrogen content was found to be significantly decreasing in the first hour of X-ray exposure. The Pb 0 signal was discovered after a few hours of soft X-ray exposure, which indicates that the CH 3NH 3PbI 3 perovskite structure undergoes a decomposition process to form metallic Pb. It is demonstrated that fresh methylammonium lead iodine contains Pb 2+ without the initial existence of Pb 0. In this study, the X-ray-induced degradation of CH 3NH 3PbI 3 perovskite films was investigated via XPS within an in situ ultrahigh vacuum system. However, few research studies have determined that the X-ray itself could cause damage to the perovskite crystals.
X-ray photoelectron spectroscopy (XPS) has been used to investigate the composition of perovskite films upon exposure to different environmental factors, such as moisture, heat, and UV light.