Shelf‐Stable Quantum‐Dot Light‐Emitting Diodes with High Operational Performance. Issue 52 (16th November 2020)

• Record Type: Journal Article
• Authors: Chen, Desui; Chen, Dong; Dai, Xingliang; Zhang, Zhenxing; Lin, Jian; Deng, Yunzhou; Hao, Yanlei; Zhang, Ci; Zhu, Haiming; Gao, Feng; Jin, Yizheng
• Is Part Of: Advanced materials. Volume 32:Issue 52(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-16
• Subjects: electron‐transporting bilayers -- in situ chemical reactions -- light‐emitting diodes -- quantum dots -- shelf stability; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202006178
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Quantum‐dot light‐emitting diodes (QLEDs) promise a new generation of high‐performance, large‐area, and cost‐effective electroluminescent devices for both display and solid‐state lighting technologies. However, a positive ageing process is generally required to improve device performance for state‐of‐the‐art QLEDs. Here, it is revealed that the in situ reactions induced by organic acids in the commonly used encapsulation acrylic resin lead to positive ageing and, most importantly, the progression of in situ reactions inevitably results in negative ageing, i.e., deterioration of device performance after long‐term shelf storage. In‐depth mechanism studies focusing on the correlations between the in situ chemical reactions and the shelf‐ageing behaviors of QLEDs inspire the design of an electron‐transporting bilayer, which delivers both improved electrical conductivity and suppressed interfacial exciton quenching. This material innovation enables red QLEDs exhibiting neglectable changes of external quantum efficiency (>20.0%) and ultralong operational lifetime ( T 95 : 5500 h at 1000 nits) after storage for 180 days. This work provides design principles for oxide electron‐transporting layers to realize shelf‐stable and high‐operational‐performance QLEDs, representing a new starting point for both fundamental studies and practical applications. Abstract : State‐of‐the‐art quantum‐dot light‐emitting diodes (QLEDs) demonstrate high operational performance but poor shelf stability. This work reveals that both positive ageing and negative ageing of the state‐of‐the‐art QLEDs are associated with in situ reactions induced by organic acids. The understanding leads to novel electron‐transporting oxide bilayers to realize shelf‐stable devices with high operational performance.