Anoshkin, Sergey S.Shishkin, Ivan I.Markina, Daria I.Logunov, Lev S.Demir, Hilmi VolkanRogach, Andrey L.Pushkarev, Anatoly P.(Makarov, Sergey V.2025-02-242025-02-242024-01-101948-7185https://hdl.handle.net/11693/116786Optical data storage, information encryption, and security labeling technologies require materials that exhibit local, pronounced, and diverse modifications of their structure-dependent optical properties under external excitation. Herein, we propose and develop a novel platform relying on lead halide Ruddlesden-Popper phases that undergo a light-induced transition toward bulk perovskite and employ this phenomenon for the direct optical writing of multicolor patterns. This transition causes the weakening of quantum confinement and hence a reduction in the band gap. To extend the color gamut of photoluminescence, we use mixed-halide compositions that exhibit photoinduced halide segregation. The emission of the films can be tuned across the range of 450-600 nm. Laser irradiation provides high-resolution direct writing, whereas continuous-wave ultraviolet exposure is suitable for recording on larger scales. The luminescent images created on such films can be erased during the visualization process. This makes the proposed writing/erasing platform suitable for the manufacturing of optical data storage devices and light-erasable security labels.EnglishCC BY 4.0 (Attribution 4.0 International Deed)https://creativecommons.org/licenses/by/4.0/Phase segregationQuantum dotsNanocrystalsEmissionArticle10.1021/acs.jpclett.3c03151