Department of Photonics, National Yang MingChiao Tung University, No. 1001 University Road, Hsinchu, 300, Taiwan.
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan.
Adv Sci (Weinh). 2023 Apr;10(10):e2206076. doi: 10.1002/advs.202206076. Epub 2023 Feb 7.
Although vacuum-deposited metal halide perovskite light-emitting diodes (PeLEDs) have great promise for use in large-area high-color-gamut displays, the efficiency of vacuum-sublimed PeLEDs currently lags that of solution-processed counterparts. In this study, highly efficient vacuum-deposited PeLEDs are prepared through a process of optimizing the stoichiometric ratio of the sublimed precursors under high vacuum and incorporating ultrathin under- and upper-layers for the perovskite emission layer (EML). In contrast to the situation in most vacuum-deposited organic light-emitting devices, the properties of these perovskite EMLs are highly influenced by the presence and nature of the upper- and presublimed materials, thereby allowing us to enhance the performance of the resulting devices. By eliminating Pb° formation and passivating defects in the perovskite EMLs, the PeLEDs achieve an outstanding external quantum efficiency (EQE) of 10.9% when applying a very smooth and flat geometry; it reaches an extraordinarily high value of 21.1% when integrating a light out-coupling structure, breaking through the 10% EQE milestone of vacuum-deposited PeLEDs.
虽然真空沉积金属卤化物钙钛矿发光二极管（PeLED）在大面积高色域显示器中有很大的应用前景，但真空升华 PeLED 的效率目前落后于溶液处理的同类产品。在这项研究中，通过在高真空下优化升华前体的化学计量比，并在钙钛矿发射层（EML）中加入超薄的下、上层，制备出高效的真空沉积 PeLED。与大多数真空沉积有机发光器件的情况不同，这些钙钛矿 EML 的性能受到上覆材料和预升华材料的存在和性质的强烈影响，从而使我们能够提高器件的性能。通过消除 Pb°的形成和钝化钙钛矿 EML 中的缺陷，PeLED 在采用非常平滑和扁平的结构时，实现了 10.9%的出色外量子效率（EQE）；当集成光取出结构时，它达到了 21.1%的非凡值，突破了真空沉积 PeLED 的 10%EQE 里程碑。
