摘要
钙钛矿材料由于具备带隙易调、光致发光量子产率高、色纯度高、载流子迁移率高、可低温溶液加工、电荷传输性能优良等优点,在照明显示领域大放异彩.近年来,通过控制化学计量比、尺寸工程和钝化缺陷等多种策略对钙钛矿微观结构进行调控,极大地提高了钙钛矿发光二极管(perovskite light emitting diodes,PeLEDs)的性能.目前,除蓝光外,绿光、红光、近红外PeLEDs的外量子效率(EQE)均已超过20%.造成蓝光器件性能停滞不前的主要原因是蓝光钙钛矿薄膜较差的覆盖率以及光谱不稳定.为提高钙钛矿薄膜质量及器件性能,本文在准二维钙钛矿材料PEAxCsPbBr3–yCly的基础上,通过引入双添加剂聚乙二醇(PEG)和溴化钾(KBr),钝化薄膜表面缺陷态,减小晶粒尺寸,抑制离子迁移与非辐射复合损耗,进而提升蓝光钙钛矿器件的效率及光谱稳定性.最终在488 nm处获得最大亮度为1049 cd·m^–2,电流效率为5.68 cd·A^–1,外量子效率为4.6%的蓝光PeLEDs.相比于不含添加剂的器件,效率提升了近3倍,且具有良好的光谱稳定性和工作寿命.
Solution-processable metal halide perovskites materials have many advantages,such as adjustable band gap,high photoluminescence quantum yield(PLQY),high color purity,high carrier mobility,low temperature solution process,excellent charge transport property and so on.These make them potential application in the display field.In the past few years,the device performance of perovskite light emitting devices(PeLEDs)have been greatly improved by manipulating the perovskite microstructures through various strategies,such as stoichiometry control,dimensional engineering,defect passivation and so on.At present,except for blue PeLEDs,the external quantum efficiencies(EQEs)over 20%have been achieved for green,red,and nearinfrared PeLEDs.The low efficiency of blue PeLEDs is retarding their potential applications in full-color display and solid-state lighting.The main reasons in blue PeLEDs are the poor film coverage of blue perovskite materials and the spectral instability during device operation.In order to improve the quality of perovskite film and device performance,the quasi two-dimensional perovskite materials phenylethylammonium cesium lead bromide chloride(PEAxCsPbBr3–yCly)are used as the main perovskite emission material,by partially replacing Br with Cl to enlarge their bandgap to achieve the blue emission.The Lewis base polyethyleneglycol(PEG)is introduced to passivate the surface trapping defects and improve perovskite film coverage.The potassium bromide(KBr)is introduced to reduce perovskite grain size,suppress mobile ion migration and exhibit excellent spectral stability.Dual additives PEG and KBr are incorporated into the quasi-2D blue perovskite for inhibiting the nonradiative losses by passivating the traps in the perovskite films.Eventually,the PEAxCsPbBr3–yCly+PEG+KBr based blue PeLEDs with the emission peak of 488 nm are accompanied,which maximum brightness,current efficiency,and external quantum efficiency reached 1049 cd·m–2,of 5.68 cd·A–1,and of 4.6%,respectively,with high color purity(the Co
作者
吴海妍
唐建新
李艳青
Wu Hai-Yan;Tang Jian-Xin;Li Yan-Qing(Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Institute of Functional Nano&Soft Materials(FUNSOM,,Soochow University,Suzhou 215123,China;School of Physics and Electronics Science,Ministry of Education Nanophotonics&Advanced Instrument Engineering Research Center,East China Normal University,Shanghai 200241,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第13期292-301,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:61520106012,61722404,51873138)资助的课题.
关键词
钙钛矿
蓝光
发光二极管
缺陷态钝化
perovskite materials
blue emission
light emitting diodes
defect passivation
