Self-assembled monolayer–based blue perovskite LEDs

作者：Ya‐Kun Wang, Fengyan Jia, Xiaoyue Li, Sam Teale, Pan Xia, Yuan Liu, Phoebe Tsz-shan Chan, Haoyue Wan, Yasser A. Hassan, Muhammad Imran, Hao Chen, Luke Grater, Ling‐Dong Sun, Gilbert C. Walker, Sjoerd Hoogland, Zheng‐Hong Lu, Chun‐Hua Yan, Liang‐Sheng Liao, Edward Hartley Sargent · 发表于：Science Advances · 年份：2023 · DOI：10.1126/sciadv.adh2140 · 被引用次数：108 · 研究领域：Perovskite Materials and Applications、Quantum Dots Synthesis And Properties、Organic Light-Emitting Diodes Research

Blue perovskite light-emitting diodes (LEDs) have shown external quantum efficiencies (EQEs) of more than 10%; however, devices that emit in the true blue—those that accord with the emission wavelength required for Rec. 2100 primary blue —have so far been limited to EQEs of ~6%. We focused here on true blue emitting CsPbBr 3 colloidal nanocrystals (c-NCs), finding in early studies that they suffer from a high charge injection barrier, a problem exacerbated in films containing multiple layers of nanocrystals. We introduce a self-assembled monolayer (SAM) active layer that improves charge injection. We identified a bifunctional capping ligand that simultaneously enables the self-assembly of CsPbBr 3 c-NCs while passivating surface traps. We report, as a result, SAM-based LEDs exhibit a champion EQE of ~12% [CIE of (0.132, 0.069) at 4.0 V with a luminance of 11 cd/m 2 ], and 10-fold–enhanced operating stability relative to the best previously reported Rec. 2100-blue perovskite LEDs.