载流子平衡方法提高量子点发光二极管效率的研究

Influence of Charge Carrier Balance on Efficiency of QD-LED

摘要:

尝试采用三种方式来平衡载流子的浓度,以提高量子点发光二极管(QLED)的外量子效率等性能:在正装结构(ITO/HIL/HTL/QD/ETL/EIL/金属阴极)的QLED的发光层和电子传输层中间插入超薄聚甲基丙烯酸甲脂(PMMA)电子阻挡层；在空穴注入和传输层方面,通过使用更加优化的HIL等来提高空穴注入和传输几率；在QD发光层方面,用短链配体来置换量子点的长链配体以增加载流子向量子点发光层中的传输效率等。在进行量子点配体交换的同时带来了量子点在正交溶剂中的可溶性优势,有利于QLED器件的全溶液法制备。

Abstract:

Three approaches were performed to achieve the charge balance in normal structure QLEDs so as to improve their external quantum efficiency:by inserting an ultra-thin PMMA electronic barrier layer between the lighting emitting layer and electron transport layer of QLED with the structure of ITO/HIL/HTL/QD/ETL/EIL/metal cathode;by optimizing the hole injection layer in the hole side to improve the probability of hole injection and transport; replacing the long chain ligands of quantum dots with short chain ones to help the charge injection and transport into the emitting layer, so as to improve the device performance. Another benefit of the ligand exchange is the improved solubility of quantum dots in orthogonal solvents of charge transport layers, which is essential for full-solution processed QLEDs.