Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
Adv Mater. 2017 Aug;29(31). doi: 10.1002/adma.201700579. Epub 2017 Jun 13.
This paper reports highly bright and efficient CsPbBr perovskite light-emitting diodes (PeLEDs) fabricated by simple one-step spin-coating of uniform CsPbBr polycrystalline layers on a self-organized buffer hole injection layer and stoichiometry-controlled CsPbBr precursor solutions with an optimized concentration. The PeLEDs have maximum current efficiency of 5.39 cd A and maximum luminance of 13752 cd m . This paper also investigates the origin of current hysteresis, which can be ascribed to migration of Br anions. Temperature dependence of the electroluminescence (EL) spectrum is measured and the origins of decreased spectrum area, spectral blue-shift, and linewidth broadening are analyzed systematically with the activation energies, and are related with Br anion migration, thermal dissociation of excitons, thermal expansion, and electron-phonon interaction. This work provides simple ways to improve the efficiency and brightness of all-inorganic polycrystalline PeLEDs and improves understanding of temperature-dependent ion migration and EL properties in inorganic PeLEDs.
本文报道了通过简单的一步旋涂法，在自组织缓冲空穴注入层和化学计量比可控的 CsPbBr 前驱体溶液上制备出均匀的 CsPbBr 多晶层，从而制备出高效、高亮的 CsPbBr 钙钛矿发光二极管（PeLEDs）。优化浓度后，PeLED 的最大电流效率为 5.39 cd A，最大亮度为 13752 cd m 。本文还研究了电流滞后的起源，这可以归因于 Br 阴离子的迁移。测量了电致发光（EL）光谱的温度依赖性，并系统地分析了光谱面积减小、光谱蓝移和线宽变宽的起源，得出了与 Br 阴离子迁移、激子热离解、热膨胀和电子-声子相互作用有关的激活能。这项工作为提高全无机多晶 PeLED 的效率和亮度提供了简单的方法，并提高了对无机 PeLED 中温度相关离子迁移和 EL 特性的理解。
