| Thickness controlled CsPbBr3 nanocrystal films for high efficiency (6% EQE) perovskite LEDs |
Heeyoung Kwack
, Min-Seong Kim, Youngjun Cho, Taehoon Kim, Jae-Min Myoung, Wooyoung Shim |
| Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seoul, 120-749, Korea |
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Received: April 28, 2025; Revised: June 6, 2025 Accepted: June 13, 2025. Published online: June 30, 2025. |
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| ABSTRACT |
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Metal halide perovskite light-emitting diodes (PeLEDs) offer high color purity and tunable emission, yet device efficiency is critically dependent on the morphology of the perovskite emissive layer (EML). In this work, we systematically explore the impact of CsPbBr3 EML thickness-ranging from 15 to 56 nm-on optical and electrical performance. Films were deposited by spin coating a CsBr:PbBr2 precursor in DMSO at varied speeds, followed by annealing at 100 °C. Steady-state and time-resolved photoluminescence measurements reveal that a 40 nm EML maximizes radiative recombination, exhibiting the highest PL intensity and an average lifetime of ~ 51 ns. SEM and AFM analyses confirm that 40 nm films achieve optimal grain uniformity and minimal defect density. Integrating this film into PeLEDs yields an external quantum efficiency (EQE) of 6%, surpassing devices with both thinner and thicker layers. These results establish a clear thickness-efficiency correlation and provide a practical design rule for high-performance perovskite LEDs in next-generation display technologies. |
| Key words:
Metal halide perovskites · Grain uniformity · LED display fabrication · Charge-hole recombination efficiency |
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