Department of Electrical Engineering, University of Washington, Seattle, WA 98195, United States of America.
Nanotechnology. 2017 Nov 10;28(45):455201. doi: 10.1088/1361-6528/aa8b8b. Epub 2017 Oct 17.
Recently, all-inorganic perovskites such as CsPbBr and CsPbI, have emerged as promising materials for light-emitting applications. While encouraging performance has been demonstrated, the stability issue of the red-emitting CsPbI is still a major concern due to its small tolerance factor. Here we report a highly stable CsPbI quantum dot (QD) light-emitting diode (LED) with red emission fabricated using an improved purification approach. The device achieved decent external quantum efficiency (EQE) of 0.21% at a bias of 6 V and outstanding operational stability, with a L lifetime (EL intensity decreases to 70% of starting value) of 16 h and 1.5 h under a constant driving voltage of 5 V and 6 V (maximum EQE operation) respectively. Furthermore, the device can work under a higher voltage of 7 V (maximum luminance operation) and retain 50% of its initial EL intensity after 500 s. These findings demonstrate the promise of CsPbI QDs for stable red LEDs, and suggest the feasibility for electrically pumped perovskite lasers with further device optimizations.
最近，全无机钙钛矿如 CsPbBr 和 CsPbI 等，已成为发光应用的有前途的材料。虽然已经证明了令人鼓舞的性能，但由于红色发射的 CsPbI 的小容忍因子，其稳定性问题仍然是一个主要关注点。在这里，我们报告了一种使用改进的纯化方法制造的具有红色发射的高稳定性 CsPbI 量子点 (QD) 发光二极管 (LED)。该器件在 6 V 的偏压下实现了相当高的外量子效率 (EQE)，为 0.21%，并且具有出色的工作稳定性，在 5 V 和 6 V 的恒定驱动电压下，分别具有 16 h 和 1.5 h 的 L 寿命 (EL 强度降至起始值的 70%)。此外，该器件可以在 7 V 的更高电压下工作 (最大亮度操作)，并且在 500 s 后仍保留其初始 EL 强度的 50%。这些发现表明 CsPbI QD 对于稳定的红色 LED 具有前景，并表明在进一步进行器件优化的情况下，电泵浦钙钛矿激光器是可行的。
