倒置QLED器件中氧化锌电子传输层的镁掺杂效应  

Study of Inverted QLED Structure with Mg2+ Doped ZnO Electron Transport Layer

作　　者：陈幸福 徐志梁 黄玲玲 王向华[1] CHEN Xingfu;XU Zhiliang;HUANG Lingling;WANG Xianghua(Key Lab of Special Display Technology,National Engineering Lab of Special Display Technology,State Key Lab of Advanced Display Technology,Academy of Opto-Electronic Technology,Hefei University of Techonlogy,Hefei 230009,CHN)

机构地区：[1]合肥工业大学光电技术研究院特种显示技术国家工程实验室省部共建现代显示技术国家重点实验室(培育基地)

出　　处：《光电子技术》2019年第4期269-274,共6页Optoelectronic Technology

基　　金：中央高校基本科研业务费专项资金资助项目(JZ2018YYPY0300)

摘　　要：基于2,7-二辛基[1]苯并噻吩并[3,2-b]苯并噻吩(C8-BTBT)与无机钙钛矿CsPbBr3 量子点构成复合发光层,采用倒置QLED器件结构(ITO/ZnO/EML/CBP/MoO3/Al),研究了氧化锌电子传输层的镁离子掺杂工艺对发光层荧光量子效率及界面稳定性的影响规律和机制。镁离子掺杂可以在一定范围内线性调控电子传输层的光学带隙,同时有效改善薄膜的表面形貌,从而提高与发光层之间的界面质量。实验发现,相对于未掺杂的ZnO薄膜,Mg0.09Zn0.91O薄膜的表面粗糙度和表面能显著下降,光学带隙则提高了0.2 eV,相应的以电子漂移为主的电导率显著下降。进一步通过调控复合发光层中的主客体比例,可以调节空穴注入比,改善载流子传输的平衡性。采用Mg0.09Zn0.91O薄膜作为电子传输层的主客体复合发光层具有更高的荧光量子效率和PL荧光寿命。研究为开发相应的倒置结构电致发光器件提供了坚实的实验依据。Mg2+doped ZnO was used as the electron transport layer(ETL) in an inverted QLED structure(ITO/ZnO/EML/CBP/MoO3/Al), where the EML layer was a composite of 2,7-dioctyl[1] benzothieno [3,2-b]benzothiophene(C8-BTBT) and inorganic CsPbBr3 quantum dots(QDs). The effects on the EM, including the light-emitting performance, interface quality and stability, were investigated. Mg2+doping may, within a certain range, linearly modulate the optical band gap of the ETL, improve the surface morphology, and therefore enhance the interface quality with the EML. Compared to undoped ZnO, the Mg0.09Zn0.91O film exhibited lower surface roughness and surface energy, but the optical band gap was increased by 0.2 eV. The increased band gap could cause a notable decrease in electrical conductivity that was dominated by electron drift current. Moreover, the balance of carrier injection, which could be quantified by the hole injection ratio, was improved via optimal guest-host mass ratio of the EML. Higher fluorescence quantum efficiency and longer PL lifetime was measured for the composite EML on Mg0.09Zn0.91O. These experimental results explicitly back the development of inverted QLED structures using the composite EMLs.

关 键 词：倒置结构 MGXZN1-XO 2 苯并噻吩并[3 2-b]苯并噻吩 CsPbBr3 

分 类 号：TN383[电子电信—物理电子学]