Kim Hong Hee, Kumi David O, Kim Kiwoong, Park Donghee, Yi Yeonjin, Cho So Hye, Park Cheolmin, Ntwaeaborwa O M, Choi Won Kook
Center for Opto-Electronic Materials and Devices, Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST) Seoul 02792 Korea
Department of Materials Science and Engineering, Yonsei University Seoul 03722 Korea.
RSC Adv. 2019 Oct 9;9(55):32066-32071. doi: 10.1039/c9ra06976c. eCollection 2019 Oct 7.
In our study, to optimize the electron-hole balance through controlling the electron transport layer (ETL) in the QD-LEDs, four materials (ZnO, ZnGaO, ZnMgO, and ZnGaMgO NPs) were synthesized and applied to the QD-LEDs as ETLs. By doping ZnO NPs with Ga, the electrons easily inject due to the increased Fermi level of ZnO NPs, and as Mg is further doped, the valence band maximum (VBM) of ZnO NPs deepens and blocks the holes more efficiently. Also, at the interface of QD/ETLs, Mg reduces non-radiative recombination by reducing oxygen vacancy defects on the surface of ZnO NPs. As a result, the maximum luminance ( ) and maximum luminance efficiency (LE) of QD-LEDs based on ZnGaMgO NPs reached 43 440 cd m and 15.4 cd A. These results increased by 34%, 10% and 27% for the and 450%, 88%, and 208% for the LE when compared with ZnO, ZnGaO, and ZnMgO NPs as ETLs.
在我们的研究中，为了通过控制量子点发光二极管（QD-LED）中的电子传输层（ETL）来优化电子-空穴平衡，合成了四种材料（ZnO、ZnGaO、ZnMgO和ZnGaMgO纳米颗粒）并将其作为ETL应用于QD-LED。通过用Ga掺杂ZnO纳米颗粒，由于ZnO纳米颗粒费米能级的增加，电子易于注入，并且随着进一步掺杂Mg，ZnO纳米颗粒的价带最大值（VBM）加深，更有效地阻挡空穴。此外，在量子点/电子传输层的界面处，Mg通过减少ZnO纳米颗粒表面的氧空位缺陷来减少非辐射复合。结果，基于ZnGaMgO纳米颗粒的QD-LED的最大亮度（ ）和最大亮度效率（LE）分别达到43440 cd m 和15.4 cd A。与作为ETL的ZnO、ZnGaO和ZnMgO纳米颗粒相比，这些结果在 方面分别提高了34%、10%和27%，在LE方面分别提高了450%、88%和208%。
