Jung, Na Eun Kang, Donghee Park, Jeehong Kim, Kitae Kim, Junho Kim, Juyoung Lee, Chang-Hee Lee, Gi-Dong Blumstengel, Sylke Morales, Nicolas Zorn List-Kratochvil, Emil J. W. Choi, Seong Jae Kim, Heung-Sik Chun, Dong Won Park, Soohyung Lee, Hyunbok Yi, Yeonjin 2026-05-07T08:00:32Z 2026-05-07T08:00:32Z 2026-05-07 2026-03 https://pubs.kist.re.kr/handle/201004/154639 Perovskite light-emitting diodes (PeLEDs) represent a compelling platform for next-generation display technologies owing to their unique optoelectronic properties. Although vacuum deposition offers the scalability and uniformity required for commercialization, vacuum-deposited PeLEDs typically exhibit lower external quantum efficiencies (EQEs) than their solution-processed counterparts. Addressing this challenge requires innovative strategies to achieve carrier confinement and suppress non-radiative recombination. In this study, we prepare high-efficiency vacuum-deposited PeLEDs through the precise compositional tailoring of Cs1−xMAxPbBr3 nanocrystals (NCs; MA = methylammonium) embedded within a wide-bandgap Cs4PbBr6 matrix via controlled co-evaporation. The addition of a small amount of PbBr2 to MABr significantly enhances the evaporation stability of the latter as well as the uniformity of the resulting films, thereby enabling controlled growth of Cs1−xMAxPbBr3 NCs. The MA content (x) in the resulting Cs1−xMAxPbBr3/Cs4PbBr6 nanostructures is precisely tuned and monitored in situ using a residual gas analyzer. At the optimal x (0.19), we achieve a remarkable 1.9-fold EQE enhancement compared with that of the MA-free device. This improvement is attributed to the controlled incorporation of MA cations, which increases the average NC size and inter-particle spacing. Structural modifications enhance photoluminescence intensity and prolong exciton decay lifetimes, indicating suppression of non-radiative recombination pathways associated with surface defects. English AIP Publishing LLC Precisely controlled organic halide evaporation for efficient vacuum-deposited perovskite light-emitting diodes Article 10.1063/5.0307016 1 Applied Physics Reviews, v.13, no.1 Applied Physics Reviews 13 1 N scie scopus 001717592900001 2-s2.0-105033682521 Physics, Applied Physics Article NANOCRYSTALS DEFECTS SIZE THIN-FILMS