Nguyen Huu Tuan, Ryu Shinyoung, Duong Anh Tuan, Lee Soonil
Phenikaa Research and Technology Institute (PRATI), A&A Green Phoenix Group, 167 Hoang Ngan, Hanoi, 10000, Viet Nam. Faculty of Electrical and Electronic Engineering, Phenikaa University, Yen Nghia, Ha-Dong District, Hanoi, 10000, Viet Nam.
Nanotechnology. 2021 Jan 27;32(15):155202. doi: 10.1088/1361-6528/abd780.
We report a five-fold luminance increase of green-light-emitting CdSe@ZnS quantum-dot LEDs (QLEDs) in response to treatment with a 2-ethoxyethanol solution of cesium carbonate (CsCO). The maximum luminous yield of CsCO-treated QLED is as high as 3.41 cd A at 6.4 V. To elucidate device-performance improvement, we model measured currents as the sum of radiative and non-radiative recombination components, which are respectively represented by modified Shockley equations. Variations in model parameters show that a shift in Fermi level, reduction of barrier heights, and passivation of mid-gap defect states are the main results of CsCO treatment. In spite of a large luminance difference, light-extraction efficiency remains the same at 9% regardless of CsCO treatment because of the similarity in optical structures.
我们报告了用碳酸铯（CsCO）的2-乙氧基乙醇溶液处理后，绿色发光的CdSe@ZnS量子点发光二极管（QLED）的亮度提高了五倍。经CsCO处理的QLED在6.4 V时的最大发光效率高达3.41 cd A。为了阐明器件性能的改善，我们将测量电流建模为辐射复合和非辐射复合分量之和，分别用修正的肖克利方程表示。模型参数的变化表明，费米能级的移动、势垒高度的降低以及带隙中间缺陷态的钝化是CsCO处理的主要结果。尽管亮度差异很大，但由于光学结构相似，无论是否经过CsCO处理，光提取效率均保持在9%不变。
