摘要
采用真空热蒸镀方法以4,4′-bis(carbazol-9-yl)biphenyl(CBP)为主体材料、以bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2′]iridium(acetylacetonate)[(t-bt)2Ir(acac)]磷光染料为掺杂剂构成黄色发光层,制备了高效白光的有机电致发光器件(OLEDs).OLEDs的器件结构为indium tin oxide(ITO)/N,N′-bis-(1-naphthyl)-N,N′-biphenyl-1,1′-biphenyl-4,4′-diamine(NPB)/CBP:(t-bt)2Ir(acac)/NPB/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(BCP)/8-hydroxyquinoline aluminum(Alq3)/Mg∶Ag,从ITO阳极开始的第一层NPB为空穴传输层,第二层超薄的NPB为蓝色发光层,BCP为空穴阻挡层和激子阻挡层,Alq3为电子传输层.结果表明,器件电压在3V启亮,在16.5V时,器件的最高亮度达到15460cd·m-2;在4V时,器件达到最大流明效率为7.5lm·W-1,器件启亮后所发出的白光光谱在低电压时随电压变化有稍微的移动,但是都在白光范围内变化.在电压达到8V后Commission Internationale de l′Eclairage(国际照明委员会)(CIE)色坐标为(0.33,0.32),并且光谱及色坐标稳定,不随电压变化而改变,与最佳的白光坐标(0.33,0.33)几乎重合.同时,从机理上解释了光谱移动和效率衰减的原因,并探讨了载流子陷阱和能量传递的关系.
High-efficiency white organic light-emitting diodes （WOLEDs） based on phosphorescent dye bis[2-（4- tert-butylphenyl）benzothiazolato-N,C2＇ ]iridium （acetylacetonate） [（t-bt）2Ir（acac）] phosphor doped 4,4＇-bis（carbazol-9-yl） biphenyl （CBP） as a yellow emitting layer were fabricated. The structure of the devices is indium-tin oxide （ITO）/N,N＇- bis-（1-naphthyl）-N,N＇-biphenyl-l,l＇-biphenyl-4,4＇-diamine （NPB）/CBP： （t-bt）2Ir（acac）/NPB/2,9-dimethyl-4,7-diphenyl- 1,10-phenanthroline （BCP）/8-hydroxyquinoline aluminum （Alqs）/Mg：Ag, and the second NPB layer from the anode was used as a blue fluorescent emitter and the first NPB layer was used as a hole transporting layer, the BCP and Alqs were used as hole blocking and electron transporting layers, respectively. The results showed that the turn-on voltage of the device was 3 V with a maximum luminance of 15460 cd·m^-2 at 16.5 V and a maximum luminance efficiency of 7.5 lm· W^-1 at 4 V, respectively. The Commission Intemationale de l＇Eclairage （CIE） coordinates located at （0.33, 0.32） remained stable at the driving voltage higher than 8 V, which is almost consistent with the optimum white CIE of （0.33, 0.33）. The purity of white light could be adjusted by doping concentration. The effects of charge carder trapping and energy transfer on the device performance were also discussed.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2007年第10期1493-1497,共5页
Acta Physico-Chimica Sinica
基金
国家杰出青年基金(60425101)
教育部新世纪优秀人才计划(NCET-06-0812)
电子科技大学中青年学术带头人计划(060206)资助
关键词
有机电致发光
白色发光
磷光
铱配合物
载流子陷阱
能量传递
Organic light-emitting diodes
White light
Phosphorescence
Iridium complex
Charge carrier trapping
Energy transfer
