周期性多发光层结构单色有机电致发光器件的研究

Effects of Periodic-multiple-emitting-layer Structures on Green and Blue Organic Light-emitting Diodes

以具有高离化能的n型小分子材料PBD、BCP作为激子限制层,用交替沉积的方式制备了分别以Alq3/PBD、NPB/BCP为周期结构多发光层的绿光、蓝光器件。周期性多发光层结构的引入大大提高了器件性能,其中,具有双周期3发光层的绿光器件最大亮度和效率分别是常规器件的10.5倍和4.4倍,具有双周期双发光层的蓝光器件最大亮度和效率分别是常规器件的2.75和1.45倍。器件性能提高的主要原因是周期性结构的引入和多发光区域的划分增加了激子产生几率。同时,周期数对器件性能有重要影响。绿光、蓝光器件电致发光(EL)谱谱峰值基本稳定,半高谱宽出现了窄化。

Two series organic light-emitting diodes（OLEDs） based on periodic multiple emitting layer（PMEL） structures have been fabricated in high vacuum deposition system. One of the structures consists of ahemating layer of Alq3 and PBD as green OLEDs. The other consists of ahernating layer of NPB and BCP as blue OLEDs. The effects of the designed structures on the narrower spectral emission and the brightness and efficiency of the OLEDs are observed. The full width at half maximum（FWHM） of OLEDs with PMEL structures decreases 4～11 nm than that of conventional OLEDs. And the highest brightness and efficiency of the green and blue diodes with PMEL structures are 10. 5 and 4.4 times,2. 75 and 1.45 times than that of conventional green and blue diodes withou PMEL structures,respectively. Such an improvement in the devices performance is attributed to the improved excltons formation in the emitting layers.