发光学报, 2016, 37 (3): 299, 网络出版: 2016-04-13
基于聚合物-量子点共混的量子点发光二极管
Quantum Dot Light-emitting Diodes with Mixed Polymer-quantum Dots Light-emitting Layer
摘要
在ITO玻璃上制备了ITO/poly(3, 4-ethylene dioxythiophene)∶poly(styrene sulphonate) (PEDOT∶PASS)/poly(N,N-bis(4-butylphenyl)-N,N-bis(phenyl)benzidine(poly-TPD)/QD/1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl(TPBi)/LiF/Al 结构的量子点发光二极管(QD-LED)。通过优化量子点的浓度, 发现浓度为30 mg/mL时的器件性能最优, 最大外量子效率(EQE)为0.83%, 最大发光亮度为4 076 cd/m2。为了进一步提高QD-LED的发光效率, 将QD掺入聚合物poly(N-vinylcarbazole) (PVK)和1,3-Bis(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)benzene (OXD-7)中, 以使得注入的电子和空穴更加平衡, 同时还有助于能量传递, 降低QD团聚及修饰QD薄膜表面, 减少激子猝灭效应等。为此, 通过旋涂和蒸镀两步法制备ITO/PEDOT∶PASS/poly-TPD/(PVK∶OXD-7)∶QD/TPBi/LiF/Al 结构的器件, 改变(PVK∶OXD-7)∶QD比例(1∶1, 1∶3, 1∶5, 0∶1), 发现(PVK∶OXD-7)∶QD为1∶3时的QD-LED具有最优性能, 最大EQE为1.97%, 相当于非掺杂器件的2.3倍, 并且发光峰没有发生偏移。
Abstract
Quantum dot light-emitting diodes (QDLED) with structure ITO/poly(3,4-ethylene dioxythiophene)∶poly(styrene sulphonate) (PEDOT∶PASS)/poly(N,N-bis(4-butylphenyl)-N,N-bis(phenyl)benzidine(poly-TPD)/QD/1,3,5-Tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi)/LiF/Al were fabricated. By optimizing the concentration of quantum dots, maximum external quantum efficiency (EQE) of 0.83% and maximum emission luminance of 4 076 cd/m2 were achieved at a QD concentration of 30 mg/mL. In order to further improve the efficiency of QDLED, QDs were doped into polymer poly(N-vinylcarbazole) (PVK) and 1,3-Bis(5-(4-(tert-butyl)phenyl)-1,3,4-oxadiazol-2-yl)benzene (OXD-7) so as to balance the injection of electrons and holes, reduce the aggregation of QDs and improve the surface of the films. Devices with structure ITO/PEDOT∶PASS/poly-TPD/(PVK∶OXD-7)∶QD/TPBi/LiF/Al were fabricated by spin coating and thermal evaporation. By optimizing the doping concentration of QDs, the maximum EQE of 1.97% is obtained, which is 2.3-fold higher than that of the undoped devices.
彭辉仁, 陈树明, 王忆. 基于聚合物-量子点共混的量子点发光二极管[J]. 发光学报, 2016, 37(3): 299. PENG Hui-ren, CHEN Shu-ming, WANG Yi. Quantum Dot Light-emitting Diodes with Mixed Polymer-quantum Dots Light-emitting Layer[J]. Chinese Journal of Luminescence, 2016, 37(3): 299.