@misc{KotVorokhtaWangetal., author = {Kot, Małgorzata and Vorokhta, Mykhailo and Wang, Zhiping and Snaith, Henry J. and Schmeißer, Dieter and Flege, Jan Ingo}, title = {Thermal stability of CH3NH3PbIxCl3-x versus [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 perovskite films by X-ray photoelectron spectroscopy}, series = {Applied Surface Science}, volume = {513}, journal = {Applied Surface Science}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2020.145596}, pages = {7}, abstract = {The thermal stability of CH3NH3PbIxCl3-x and [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 perovskite films was studied in-situ by X-ray photoelectron spectroscopy. It was found that below 85 °C both of them are relatively stable. After annealing above 85 °C, we observe a clear perovskite surface decomposition, i.e., a release of organic cations and creation of "metallic lead". The mixed cation lead mixed halide perovskite, however, decomposes at a much lower rate. For both perovskite films, the metallic to the total lead ratio changes with the same rate for the same annealing temperatures. The release of A-site cations from the ABX3 crystal structure of perovskite and/or creation of "metallic lead" causes also a small shift of the valence band maximum towards the Fermi level. The release of [HC(NH2)2]± or Cs± is not as significant as the release of CH3NH3±; therefore, it may explain why [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 solar cells are thermally more stable. Therefore, as the stability of CH3NH3PbIxCl3-x is same as the stability of [HC(NH2)2]0.83Cs0.17PbI2.7Br0.3 below 85 °C, there must be more severe degradation pathways that are currently underappreciated on the solar cell level.}, language = {en} }