Deng Lingling, Yang Jiaqi, Zhan Nan, Yu Tianyan, Yu Hongtao, Chen Shufen
Opt Lett. 2019 Feb 15;44(4):983-986. doi: 10.1364/OL.44.000983.
Solution-processed white organic light-emitting diodes (WOLEDs) with silica-coated silver nanocubes (Ag@SiO NCs) incorporated at the interface of a hole transporting layer and emission layer are studied. The concentration of Ag@SiO NCs is varied to investigate the effect of Ag@SiO NCs on the performances of WOLEDs. Owing to the sharp edges and corners, Ag NCs greatly improve the radiative rate and emission intensity of nearby blue excitons. The blue emission at different Ag@SiO NC concentrations determines the performance of the WOLEDs. The emission of the orange excitons is strengthened by the high concentration of Ag@SiO NCs, which slightly influences the device performance. On the other hand, the SiO shell and some SiO nanospheres coexisting with Ag NCs reduce the hole transporting, improving the carrier balance in the WOLEDs. The experimental and simulated results also show that excessive Ag@SiO NCs may cause a rough film surface, unbalanced carrier injection, and fluorescence quenching, which decreases the device performance. The optimized WOLED with a proper concentration of Ag@SiO NCs has a peak current efficiency of 53.9 cd/A, acquiring a significant enhancement factor of 77.3% compared to the control device without Ag@SiO NCs.
研究了在空穴传输层和发光层界面处掺入二氧化硅包覆银纳米立方体（Ag@SiO NCs）的溶液法制备的白色有机发光二极管（WOLEDs）。改变Ag@SiO NCs的浓度以研究其对WOLEDs性能的影响。由于尖锐的边缘和角落，Ag纳米立方体极大地提高了附近蓝色激子的辐射率和发射强度。不同Ag@SiO NC浓度下的蓝色发射决定了WOLEDs的性能。高浓度的Ag@SiO NCs增强了橙色激子的发射，这对器件性能有轻微影响。另一方面，SiO壳层和与Ag纳米立方体共存的一些SiO纳米球减少了空穴传输，改善了WOLEDs中的载流子平衡。实验和模拟结果还表明，过量的Ag@SiO NCs可能会导致薄膜表面粗糙、载流子注入不平衡和荧光猝灭，从而降低器件性能。具有适当浓度Ag@SiO NCs的优化WOLED的峰值电流效率为53.9 cd/A，与没有Ag@SiO NCs的对照器件相比，获得了77.3%的显著增强因子。
