Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, 70101, Taiwan.
Adv Mater. 2017 Jun;29(23). doi: 10.1002/adma.201606859. Epub 2017 Apr 10.
Inorganic metal halide perovskite nanocrystals (NCs) have been employed universally in light-emitting applications during the past two years. Here, blue-emission (≈470 nm) Cs-based perovskite NCs are derived by directly mixing synthesized bromide and chloride nanocrystals with a weight ratio of 2:1. High-brightness blue perovskite light-emitting diodes (PeLEDs) are obtained by controlling the grain size of the perovskite films. Moreover, a white PeLED is demonstrated for the first time by blending orange polymer materials with the blue perovskite nanocrystals as the active layer. Exciton transfer from the blue nanocrystals to the orange polymers via Förster or Dexter energy transfer is analyzed through time resolved photoluminescence. By tuning the ratio between the perovskite nanocrystals and polymers, pure white light is achieved with the a CIE coordinate at (0.33,0.34).
在过去的两年中，无机金属卤化物钙钛矿纳米晶体（NCs）已被广泛应用于发光应用中。在这里，通过直接混合合成的溴化物和氯化物纳米晶体，以重量比 2:1 得到蓝色发射（≈470nm）的 Cs 基钙钛矿 NCs。通过控制钙钛矿薄膜的晶粒尺寸，获得了高亮度的蓝色钙钛矿发光二极管（PeLEDs）。此外，首次通过将橙色聚合物材料与蓝色钙钛矿纳米晶体混合作为有源层，展示了白色 PeLED。通过Förster 或 Dexter 能量转移，从蓝色纳米晶体到橙色聚合物的激子转移通过时间分辨光致发光进行分析。通过调整钙钛矿纳米晶体和聚合物之间的比例，可以实现纯白光，CIE 坐标为（0.33,0.34）。
