Nong Yingyi, Yao Jisong, Li Jiaqi, Xu Leimeng, Yang Zhi, Wang Shalong, Song Jizhong
Key Laboratory of Materials Physics of Ministry of Education, Laboratory of Zhongyuan Light, School of Physics, Zhengzhou University, Zhengzhou 450051, China.
Nano Lett. 2024 Nov 20;24(46):14594-14601. doi: 10.1021/acs.nanolett.4c02600. Epub 2024 Oct 23.
Perovskite quantum dots (QDs) are emerging as excellent light sources for light-emitting diodes (LEDs). However, the performance of blue perovskite QD-based LEDs (QLEDs) still lags behind that of red and green counterparts, which is hindered by blue perovskite QDs with broad bandgaps that tend to increase nonradiative recombination. Here, we designed a gradient energy for hole injection utilizing multiple hole injection layers (HTLs) combined with carbazole-based small-molecule modification to reduce the hole injection barrier between HTLs and QD layers and improve the hole injection efficiency, realizing efficient exciton recombination in blue perovskite QLEDs. Moreover, the QD film on the designed HTLs demonstrates a lower surface roughness and improved photoluminescence properties. The optimized blue CsPbClBr QLEDs exhibit an impressive external quantum efficiency of 20.7% with an electroluminescence peak at 475 nm and a turn-on voltage of 2.6 V, representing the state-of-the-art for blue perovskite LEDs emitting in the range of 460-480 nm.
钙钛矿量子点（QDs）正成为发光二极管（LEDs）的优秀光源。然而，基于蓝色钙钛矿量子点的发光二极管（QLEDs）的性能仍落后于红色和绿色同类产品，这受到宽带隙蓝色钙钛矿量子点的阻碍，宽带隙量子点往往会增加非辐射复合。在此，我们利用多个空穴注入层（HTLs）结合咔唑基小分子修饰设计了用于空穴注入的梯度能量，以降低HTLs与量子点层之间的空穴注入势垒并提高空穴注入效率，从而在蓝色钙钛矿QLEDs中实现高效激子复合。此外，在设计的HTLs上的量子点薄膜表现出更低的表面粗糙度和改善的光致发光性能。优化后的蓝色CsPbClBr QLEDs表现出令人印象深刻的20.7%的外量子效率，电致发光峰值在475 nm，开启电压为2.6 V，代表了在460 - 480 nm范围内发光的蓝色钙钛矿LEDs的当前最高水平。
