Origin of Positive Aging in Quantum-Dot Light-Emitting Diodes

Su, Qiang; Sun, Yizhe; Zhang, Heng; Chen, Shuming

2018-10

10.1002/advs.201800549

Advanced Science   影响因子和分区

2198-3844

The phenomenon of positive aging, i.e., efficiency increased with time, is observed in quantum-dot light-emitting diodes (QLEDs). For example, the external quantum efficiency (EQE) of blue QLEDs is significantly improved from 4.93% to 12.97% after storage for 8 d. The origin of such positive aging is thoroughly investigated. The finding indicates that the interfacial reaction between Al cathode and ZnMgO electron transport layer accounts for such improvement. During shelf-aging, the Al slowly reacts with the oxygen from ZnMgO, and consequently, leads to the formation of AlOx and the production of oxygen vacancies in ZnMgO. The AlOx interlayer reduces the electron injection barrier while the oxygen vacancies increase the conductivity of ZnMgO and, as a result, the electron injection is effectively enhanced. Moreover, the AlOx can effectively suppress the quenching of excitons by metal electrode. Due to the enhancement of electron injection and suppression of exciton quenching, the aged blue, green, and red QLEDs exhibit a 2.6-, 1.3-, and 1.25-fold efficiency improvement, respectively. The studies disclose the origin of positive aging and provide a new insight into the exciton quenching mechanisms, which would be useful for further constructing efficient QLED devices.

exciton quenching interfacial reaction light-emitting diodes positive aging quantum-dots

SCI ; EI

英语

第一 ; 通讯

Shenzhen Peacock Plan[KQTD2015071710313656]

Chemistry ; Science & Technology - Other Topics ; Materials Science

Chemistry, Multidisciplinary ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary

WOS:000447632000004

WILEY

20183105648736

Aluminum ; Diodes ; Efficiency ; Electrodes ; Electron injection ; Electron transport properties ; Excitons ; Light emitting diodes ; Magnesium compounds ; Nanocrystals ; Organic light emitting diodes (OLED) ; Oxygen vacancies ; Quenching ; Semiconductor quantum dots ; Surface chemistry ; Zinc compounds

Heat Treatment Processes:537.1 ; Aluminum:541.1 ; Semiconductor Devices and Integrated Circuits:714.2 ; Physical Chemistry:801.4 ; Production Engineering:913.1 ; Quantum Theory; Quantum Mechanics:931.4 ; Crystalline Solids:933.1

Web of Science

Southern Univ Sci & Technol, Dept Elect & Elect Engn, Shenzhen 518055, Peoples R China

Su, Qiang,Sun, Yizhe,Zhang, Heng,et al. Origin of Positive Aging in Quantum-Dot Light-Emitting Diodes[J]. Advanced Science,2018,5(10).

Su, Qiang,Sun, Yizhe,Zhang, Heng,&Chen, Shuming.(2018).Origin of Positive Aging in Quantum-Dot Light-Emitting Diodes.Advanced Science,5(10).

Su, Qiang,et al."Origin of Positive Aging in Quantum-Dot Light-Emitting Diodes".Advanced Science 5.10(2018).