摘要
利用高真空多源型有机分子沉积系统分别制备了不同负电极为Al、LiF/Al和Mg∶Ag的有机小分子多层电致发光器件 ,比较了不同负极对以五苯基环戊二烯 (PPCP)为发光层的蓝光有机电致发光器件性能的影响 ,发现以LiF/Al作负极的器件在综合性能上优于其它器件。其中器件ITO/TPD/PPCP/Alq/LiF/Al蓝光发射的最大发光亮度达 2 3 75cd/m2 ,最大发光效率为 0 2 6lm/W。
Since the discovery of efficient organic light emitting devices (OLEDs), there has been considerable interest in developing OLEDs with high brightness, high efficiency, and long lifetime for display applications. This has resulted in substantial research activity to increase the carrier mobility, color gamut, and electroluminescence efficiency of organic materials, as well as to improve electron and hole injection by the contacts. The brightness and efficiency of OLEDs depend on the number density of electrons and holes in the emission layer, so that effective charge injection into the organic materials is critical for optimum device performance. For the hole injecting contact, indium tin oxide (ITO) is often used because of its transparency and high work function (5 1eV). On the other hand, an efficient electron injecting contact is usually a low work function material such as magnesium, calcium, or lithium. These materials are typically alloyed with metal such as aluminum or silver to form contact that is both more stable and more resistant to corrosion upon exposure to air. At the same time inserting an insulating layer between cathode and organic material is effective means to improve current injection and EL. In this paper, some multilayers OLEDs were fabricated using Al,LiF/Al and Mg∶Ag as cathode respectively while ITO-coated glass as anode, 1,2,3,4,5 pentaphenyl 1,3 cyclopentadiene(PPCP) as emitter, N,N′ diphenyl N,N′ bis(3 methyl phenyl) (1,1′ biphenyl) 4,4′ diamine(TPD) as hole transport layer, tris(8 hydroxyquinoline)aluminum(Alq), 2 (4 biphenylyl) 5 (4 tertbutyl phenyl) 1,3,3 oxadiazole(PBD) or 2,5 bis(5 tert butyl 2 benzoxazolyl)thiophene(BBOT) as electron transport layer, respectively. And effect of cathode on performance of blue OLEDs was studied. All organic layers were prepared by a high vacuum multisource type organic molecular deposition system. From result, it is found that the performance of device with LiF/Al as cathode excels that of the de
出处
《发光学报》
EI
CAS
CSCD
北大核心
2000年第3期265-268,共4页
Chinese Journal of Luminescence
基金
国家自然科学基金资助课题!( 5 9790 5 0 0 1)
