高亮度微腔有机电致发光器件

High luminance microcavity organic light-emitting diodes

为了实现有机电致发光器件(OLED)发射光谱的窄化和高亮度,真空热蒸镀具有不同微腔结构的OLED(MOLED):玻璃衬底/分布式布拉格反射器(DBR)(1～4对的SiO2/Ta2O5层)/ITO/空穴传输层(HTL,α-NPD)/发光层(EML,Alq3:Rubrene或Alq3:Coumarin6)/电子传输层(ERL,Alq3)LiF/Mg/Ag,其中沉积DBR结构采用电子束沉积法。实验表明:该MOLED的发射光谱半波长宽度(FWHM)随DBR层数的增加而减小至最小值10nm;并且在2层DBR时,掺杂Rubrene器件得到更大的电流效率,约20cd/A,最大亮度为2.6×105cd/m2。研究发现,蓝光MOLED能够对自发光产生吸收现象,降低了出光效率。

In order to achieve a high-luminance and high purity OLED, vapor thermal evaporation was used to fabricate the organic light-emitting diodes with different microcavity structures （MOLEDs）： glass/distributed Bragg resonator （DBR） （ 1 - 4 pairs of SiO2/Ta2O5 ）/ITO/hole transport layer （ a- NPD） / light-emitting layer（EML） （ Alq3 ： Rubrene or Alq3 ： Coumarin6） / electron transport layer （ Alq3 ） / LiF/Mg/Ag,in which the DBR structure was deposited by e-beam deposition. The experimental results indicate that the full wavelength of half maximum of the electroluminescence spectrum decreased to 10 nm with the decrease in layer number of DBR. Moreover,for MOLED with two pairs of DBR,the device doped with rubrene in EML obtained a current efficiency of about 20 cd/A and the highest luminance reached 2. 6 ×10^5 cd/m^2. In addition, coumarin6 doped MOLED is able to absorb self-luminescence which reduce the light-coupling efficiency.