溴基钙钛矿量子点发光二极管的制备及性能优化

Preparation and performance optimization of bromine-based perovskite quantum dot light-emitting diodes

为了研究量子点发光层薄膜厚度对钙钛矿量子点发光二极管(perovskite quantum dot lightemitting diodes,PeLED)电-光转换效率的影响,采用配体辅助再沉淀法(ligand assisted reprecipitation,LARP)室温合成铯铅溴(CsPbBr_(3))钙钛矿量子点,并用其制备出稳定绿光发射的PeLED.通过比较不同发光层厚度CsPbBr_(3)PeLEDs的发光效率,获得量子点发光层的最佳膜厚为43.2 nm.采用CsPbBr_(3)作为PeLED发光层时的器件外量子效率(external quantum efficiency,EQE)较低,为提高PeLED的电-光转换效率,用FASn_(0.3)Pb_(0.7)Br_(3)量子点替代CsPbBr_(3)作为发光层,并选用聚乙烯基咔唑(polyvinylcarbazole,PVK)、聚[(N,N'-(4-正丁基苯基)-N,N'-二苯基-1,4-苯二胺)-ALT-(9,9-二正辛基芴基-2,7-二基)](poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-butylphenyl)))],TFB)、聚[双(4-苯基)(4-丁基苯基)胺](poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzi,Poly-TPD)和聚[双(4-苯基)(2,4,6-三甲基苯基)胺](poly[bis(4-phenyl)(2,4,6-triMethylphenyl)aMine,PTAA])等4种不同的空穴传输层.光致发光光谱和电学性能测试结果表明,空穴传输层为TFB时,FASn_(0.3)Pb_(0.7)Br_(3)PeLED由于具有较高的空穴迁移率,EQE最高可达4.2%.实验结果证明TFB适于作为FASn_(0.3)Pb_(0.7)Br_(3)PeLED的空穴传输层材料.

In order to investigate the effect of the thickness of the perovskite quantum dots light-emitting layer on the electro-optical conversion efficiency of perovskite quantum dot light-emitting diodes(PeLEDs),the cesium lead bromide(CsPbBr_(3))perovskite quantum dots were synthesized by ligand assisted reprecipitation(LARP)at room temperature,and the green PeLEDs with good stability were prepared.By comparing the luminous efficiency of CsPbBr_(3)PeLEDs with the different thicknesses of light-emitting layer,we obtained that the optimal film thickness of the quantum dot light-emitting layer is 43.2 nm,but the external quantum efficiency(EQE)of CsPbBr_(3)PeLEDs is very low.To improve the electro-optical conversion efficiency of the device,FASn_(0.3)Pb_(0.7)Br_(3)Br_(3)instead of CsPbBr_(3)quantum dots are used as the light-emitting layer,and the four different hole transport layers,such as polyvinylcarbazole(PVK),poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-butylphenyl)(TFB),poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzi(Poly-TPD)and poly[bis(4-phenyl)(2,4,6-triMethylphenyl)aMine](PTAA),are selected to investigate the effects of different hole transport layers on the photoelectric properties of PeLEDs.The photoluminescence spectra and electrical performance test results show that when the hole transport layer is TFB,FASn_(0.3)Pb_(0.7)Br_(3)Br_(3)PeLED has a high hole mobility,and the EQE can reach up to 4.2%.The experimental results show that TFB is a suitable material for the hole transport layer of FASn_(0.3)Pb_(0.7)Br_(3)Br_(3)PeLED.