OLED结构优化和光电性能提高的综合实验设计

Comprehensive experimental design of structural optimization and photoelectrical properties improvement of OLED

为了改善蓝绿色有机发光二极管的效率,设计具有了阶梯能级结构和主体掺杂混合发光层的器件结构,其中5tCzBN为发光客体材料,DPEPO为主体掺杂材料。在器件结构中引入HAT-CN作为缓冲层(空穴注入层)修饰ITO表面,构建性能优良的OLED,其结构为ITO/HAT-CN/NPB/5tCzBN:DPEPO/DPEPO/Bphen/LiF/Al。OLED的最大电流效率、外量子效率和功率效率分别为46.05 cd/A、18.11%和35.46 lm/W。在阳极和空穴传输层之间引入HAT-CN作为空穴注入层,形成HAT-CN/NPB异质结,可有效地提高载流子输运效率,降低OLED的启亮电压,提高器件的发光效率。实验结果表明,OLED内部载流子平衡是提高电致发光效率的关键。

To improve the efficiency of organic light-emitting diodes(OLEDs)with blue-green light,we designed device structures with step level energy structure and hybrid film as the light emitting layer,which included DPEPO as host matrix material and 5tCzBN as guest material.The HAT-CN-modified ITO surface was used as the anode in the fabrication of OLED with a configuration of ITO/HAT-CN/NPB/5tCzBN:DPEPO/DPEPO/Bphen/LiF/Al,where HAT-CN was the hole-injection layer(HIL).The maximum current efficiency,external quantum efficiency and power efficiency of OLED devices reach as high as 46.05 cd/A,18.11%,35.46 lm/W,respectively.The introduction of HAT-CN as the hole injection layer between the anode and the hole transport layer forms organic heterojunction with a HAT-CN/NPB structure,which can effectively improve the carrier transport efficiency,reduce the turn-on voltage of the OLED device and improve the luminous efficiency of the devices.Results show that charge balance is the key to improve the electroluminescence efficiency of OLEDs,which provides information points to the direction to improve the performance of OLEDs.