Yu Hongwei, Zhang Jiaming, Long Teng, Xu Mengxin, Feng Haiwei, Zhang Letian, Liu Shihao, Xie Wenfa
State Key Laboratory of Integrated Optoelectronics, College of Electronics Science and Engineering, Jilin University, Changchun 130012, People's Republic of China.
J Phys Chem Lett. 2020 Nov 5;11(21):9019-9025. doi: 10.1021/acs.jpclett.0c02419. Epub 2020 Oct 11.
Blade-coating is a potential method for preparing all-solution-processed quantum dot light-emitting diodes (QLEDs) because of its high material utilization and large-scale preparation compatibility. However, it is a challenge to prepare uniform-emitting, high-performance QLEDs by blade coating because of film uniformity issues. Here, we report an efficient all-blade-coated QLED through solvent engineering. A binary water/methanol solvent is used to decrease the surface tension, leading to uniform blade-coating poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films. The binary solvent also enhances hole transport abilities because of phase separations and chain reorientations of PEDOT and PSS chains. The uniformity of a poly(-vinylcarbazole) (PVK) layer is also improved by using a chlorobenzene/toluene binary solvent to facilitate the spontaneous spreading of the PVK solution on the substrate. This enables the successful preparation of an efficient QLED with a maximum external quantum efficiency of 12.48%, which is about 2.6 times the value of the QLED without solvent engineering.
刮涂法是制备全溶液处理量子点发光二极管（QLED）的一种潜在方法，因为其材料利用率高且与大规模制备兼容。然而，由于薄膜均匀性问题，通过刮涂法制备发光均匀、高性能的QLED是一项挑战。在此，我们报道了一种通过溶剂工程实现的高效全刮涂QLED。使用二元水/甲醇溶剂来降低表面张力，从而得到均匀刮涂的聚（3,4-乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT:PSS）薄膜。由于PEDOT和PSS链的相分离和链重排，二元溶剂还增强了空穴传输能力。通过使用氯苯/甲苯二元溶剂促进聚（乙烯基咔唑）（PVK）溶液在基板上的自发铺展，PVK层的均匀性也得到了改善。这使得能够成功制备出高效QLED，其最大外量子效率为12.48%，约为未进行溶剂工程的QLED值的2.6倍。
