We show that the decomposition of caesium lead halide perovskite nanocrystals under continuous X-ray illumination depends on the surface ligand. For oleic acid/oleylamine, we observe a fast decay accompanied by the formation of elemental lead and halogen. Upon surface functionalization with a metal porphyrin derivative, the decay is markedly slower and involves the disproportionation of lead to Pb0 and Pb3+. In both cases, the decomposition is preceded by a contraction of the atomic lattice, which appears to initiate the decay. We find that the metal porphyrin derivative induces a strong surface dipole on the nanocrystals, which we hold responsible for the altered and slower decomposition pathway. These results are important for application of lead halide perovskite nanocrystals in X-ray scintillators.
Bibliographical noteFunding Information:
This work was supported by the DFG under grants SCHE1905/8-1 (project no. 424708673) and SCHE1905/9-1 as well as the Carl Zeiss Stiftung (Forschungsstrukturkonzept “Interdisziplinäres nanoBCP-Lab”). The Authors would like to thank Dmitry Lapkin and Jerome Carnis for help with the WAXS measurements. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III synchrotron facility and we would like to thank the beamline staff for assistance in using the Coherence Application P10 beamline.
© 2022 The Royal Society of Chemistry
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry