基于新型空穴传输材料的有机电致发光器件的研究

利用真空蒸镀方法以N2,N7-二(间甲苯胺基)-N2,N7-二苯基-2,7-二胺基-9,9-二甲基芴2,7-bis(pmethoxyphenyl-m'-tolylamino)9,9-dimethylfluorene,TPF-OMe]为空穴传输层、8-羟基喹啉铝tris(8-hydroxyquinolinato)aluminum,Alq3)]作为发光层及电子传输层,制备了双层器件.与制作的典型双层结构N,N'-二苯基-N,N'-二(3-甲基苯基)-1,1'-联苯-4,4'-二胺N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-1,1'-biphenyl-4,4'diamine,TPD/Alq3]器件相比,电流密度较大,发光效率低,发光谱峰为516 nm,色坐标为(0.30,0.53),为Alq3材料发光.以TPF-OMe为发光层兼空穴传输层,2,9-二甲基-4,7-二苯基-1,10-菲罗啉(2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline,bathocuproine或BCP)为空穴阻挡层,Alq3为电子传输层,制作三层有机电致发光器件.结果表明,光谱峰值在414 nm,色坐标为(0.20,0.24),为蓝色光,是TPF-OMe材料本身发光,器件在15 V电压下电流密度为1137 mA/cm2,亮度为900 cd/m2,在3 V偏压下有最大流明效率,为0.11 lm/W.基于TPF-OMe材料的器件的击穿温度比基于TPD材料的器件高近20℃,原因可能在于TPF-OMe材料比TPD材料高19℃的玻璃化转变温度(Tg).

Organic Light-Emitting Devices Based on Novel Hole Transport Layer

Double-layer organic light-emitting devices were fabricated by conventional vacuum deposition method using 2,7-bis (p-methoxyphenyl-m′-tolylamino)-9,9-dimethylfluorene (TPF-OMe) and N, N′-biphenyl-N, N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) as hole transport layer (HTL), respectively, and tris(8-hydroxyquinolinato) aluminum (Alq3) as electron transport and light emitting layer (ETL and EML). The devices consisting of TPF-OMe as HTL show higher current density but lower luminous efficiency, and a green-blue emission at 516 nm, CIE (0.30,0.53), which is Alq3 electroluminescence spectrum. The devices with the structure of ITO/TPF-OMe (40 nm)/ 2,9-dimethyl-4,7- dipheny 1-1,10-phenanthroline (bathocuproine or BCP) (5 nm)/Alq3 (35nm)/Mg∶Ag (300 nm) was also fabricated, which showed blue light emission of TPF-OMe at the peak of 414 nm, CIE coordinates of (0.20, 0.24), current density of 1137 mA/cm2 and luminance of 900 cd/m2 at 15 V, the maximum luminous efficiency 0.11 lm/W at 3 V. Also, the devices based on TPF-OMe has 20 ℃ higher thermal stability compared with that using TPD as HTL, which may be caused by the 19 ℃ higher glass-transition temperature (Tg) of TPF-OMe than TPD material.