Lee Jae-Sung, Kang Byoung-Ho, Kim Sae-Wan, Kwon Jin-Beom, Kim Ok-Sik, Byun Young Tae, Kwon Dae-Hyuk, Bae Jin-Hyuk, Kang Shin-Won
Sensor System Research Center, Korea Institute of Science and Technology (KIST), 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul, 02792, Republic of Korea.
Institute of Technology, DONG-A CARBON TECHNOLOGY, 41-3, Gyo 8-Gil, Buksam-eub, Chilgok-gun, Gyeongsangbuk-do, Republic of Korea.
Sci Rep. 2019 Apr 23;9(1):6357. doi: 10.1038/s41598-019-42925-0.
Quantum-dot (QD) light-emitting devices (QLEDs) have been attracting considerable attention owing to the unique properties of process, which can control the emission wavelength by controlling the particle size, narrow emission bandwidth, and high brightness. Although there have been rapid advances in terms of luminance and efficiency improvements, the long-term device stability is limited by the low chemical stability and photostability of the QDs against moisture and air. In this study, we report a simple method, which can for enhance the long-term stability of QLEDs against oxidation by inserting Al into the shells of CdSe/ZnS QDs. The Al coated on the ZnS shell of QDs act as a protective layer with AlO owing to photo-oxidation, which can prevents the photodegradation of QD with prolonged irradiation and stabilize the device during a long-term operation. The QLEDs fabricated using CdSe/ZnS/Al QDs exhibited a maximum luminance of 57,580 cd/m and current efficiency of 5.8 cd/A, which are significantly more than 1.6 times greater than that of CdSe/ZnS QDs. Moreover, the lifetimes of the CdSe/ZnS/Al-QD-based QLEDs were significantly improved owing to the self-passivation at the QD surfaces.
量子点（QD）发光器件（QLED）因其独特的工艺特性而备受关注，该特性可通过控制粒径来控制发射波长、发射带宽窄且亮度高。尽管在亮度和效率提升方面取得了快速进展，但QD对水分和空气的化学稳定性和光稳定性较低，限制了器件的长期稳定性。在本研究中，我们报告了一种简单的方法，即通过在CdSe/ZnS QD的壳层中插入Al来提高QLED的长期抗氧化稳定性。由于光氧化作用，涂覆在QD的ZnS壳层上的Al会形成具有AlO的保护层，这可以防止QD在长时间照射下发生光降解，并在长期运行过程中稳定器件。使用CdSe/ZnS/Al QD制造的QLED的最大亮度为57,580 cd/m，电流效率为5.8 cd/A，分别比CdSe/ZnS QD高出1.6倍以上。此外，基于CdSe/ZnS/Al-QD的QLED的寿命由于QD表面的自钝化而显著提高。
