钙钛矿发光二极管外量子效率提升策略  

Strategies to improve the external quantum efficiency of perovskite light-emitting diode

作　　者：俞文锦 张雨晴 曲波[1] 陈志坚[1] 肖立新[1] Wenjin Yu;Yuqing Zhang;Bo Qu;Zhijian Chen;Lixin Xiao(State Key Laboratory for Mesoscopic Physics,Department of Physics,Peking University,Beijing 100871,China)

机构地区：[1]北京大学物理学院,人工微结构和介观物理国家重点实验室,北京100871

出　　处：《科学通报》2021年第17期2151-2161,共11页Chinese Science Bulletin

基　　金：国家重点研发计划(2016YFB0401003);国家自然科学基金(U1605244)资助。

摘　　要：金属卤化物钙钛矿(metal halide perovskite,MHP)因其优异的光电性能以及可溶液加工,有潜力成为下一代显示和照明设备的核心发光材料.早在20世纪90年代,就有研究人员试图将层状MHP作为发光材料,制备钙钛矿发光二极管(perovskite light-emitting diode,PeLED).但受制于不成熟的成膜方法和器件结构,器件最终只在110 K的低温下实现了正常点亮.2014年,Snaith等人首次实现了室温下正常点亮的PeLED器件.自此,越来越多的研究者关注并投入到PeLED器件的研究中.经过近5年的发展,器件外量子效率(external quantum efficiency,EQE)已得到显著提升,近红外光器件从最初的0.8%提升到20.7%,绿光器件从最初的0.1%提升到20.3%,而天蓝光器件和蓝光器件目前最高的EQE分别是12.1%和9.5%.本文从原理出发分析了限制器件外量子效率的因素.钙钛矿发光层的发光量子产率是决定器件EQE的关键因素,而电荷平衡因子和光耦合因子是进一步提升器件EQE的重要因素.由此,本文从提升钙钛矿发光层发光量子产率与调整器件结构提升电荷平衡因子和光耦合因子两方面,总结了目前文献中提升器件外量子效率的策略,指出了PeLED领域目前亟待解决的核心问题和未来发展的方向.Metal halide perovskite(MHP)has the potential to become the core luminescent material for the next generation of display and lighting equipment due to its excellent photoelectric properties and solution processible.Its unique crystal structure and flexible elemental composition enable it to have adjustable high-color-purity ultra-wide color gamut and bipolar ultra-fast mobility.As early as the 1990 s,researchers attempted to prepare perovskite light-emitting diode(Pe LED)using layered MHP as the light-emitting material.However,due to the immature membrane forming method and device structure,the device can only light up normally at 110 K.In 2014,Snaith et al first realized Pe LED devices that were normally lit at room temperature.After nearly 5 years’development,the external quantum efficiency(EQE)of Pe LED has been significantly improved,from 0.76%to 20.7%for near-infrared devices and from 0.1%to 20.31%for green devices.At the same time,the highest EQEs for sky-blue devices and blue devices are 12.1%and 9.5%,respectively.In this paper,the factors limiting device EQE are analyzed in principle.The limitation of device EQE can be considered from four factors:Transition selection factorχ,charge balance factorηr,optical coupling factorηout and photoluminescence quantum yieldφPL.The photoluminescence quantum yield of perovskite layer is the key factor to determine device EQE,while the charge balance factor and the light coupling factor are the important factors to further improve device EQE.The transition selective factor of perovskite is generally considered to be 100%,which means that both triplet and singlet states of perovskite materials are involved in luminescence.The charge balance factor mainly depends on the choice of electron transport material and hole transport material in the device structure,while the optical coupling factor depends on the morphology of the device film and the external light emission structure in the device.Last but not the least,the photoluminescence quantum yield depends on the ty

关 键 词：金属卤化物钙钛矿 发光二极管 外量子效率 维度调控 缺陷钝化 

分 类 号：TN312.8[电子电信—物理电子学] TB34[一般工业技术—材料科学与工程]