基于新型空穴传输材料的有机电致发光器件的研究

Organic Light-Emitting Devices Based on Novel Hole Transport Layer

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-t′olylamino)-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)。

Double-layer organic light-emitting devices were fabricated by conventional vacuum deposition method using 2,7-bis （p-methoxyphenyl-m-tolylamino）-9,9-dimethylfluorene （TPFOMe） 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/cm^2 and luminance of 900 cd/m^2 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.