利用CsN3n型掺杂电子传输层改善OLED器件性能的研究

为了能够有效地提高电子的注入和传输能力, 改善有机电致发光器件的性能, 本文利用CsN3作为n型掺杂剂, 对有机电子传输材料Bphen进行n型电学掺杂, 制备了结构为ITO/MoO3(2 nm)/NPB(50 nm)/Alq3(30 nm)/Bphen(15 nm)/Bphen∶CsN3(15 nm,x%, x=10,15,20)/Al(100 nm)的器件。实验结果表明, CsN3是一种有效的n型掺杂剂, 以掺杂层Bphen∶CsN3 作为电子传输层, 可以有效地降低电子的注入势垒, 改善器件的电子注入和传输能力, 从而降低器件的开启电压, 同时提高了器件的亮度和发光效率。在掺杂浓度为10%时器件的性能最优, 开启电压仅为2.3 V, 在7.2 V的驱动电压下, 达到最大亮度29 060 cd/m2, 是非掺杂器件的2.5倍以上。当驱动电压为6.6 V时, 达到最大电流效率3.27 cd/A。而当掺杂浓度进一步提高时, 由于Cs扩散严重, 发光区形成淬灭中心, 造成器件的效率下降。

Abstract

To enhance the electron injecting and transporting ability and improve the performance of organic light-emitting device,the organic electron transport material Bphen was electrically doped by using CsN3 as n-type dopant in this work. The devices of ITO/MoO3(2 nm)/NPB(50 nm)/Alq3(30 nm)/Bphen(15 nm)/Bphen: CsN3(15 nm, x %, x=10,15,20)/Al(100 nm) were prepared. The experimental results show that the CsN3 is an effective n-type dopant. The electron injection barriers was reduced and the electron injecting and transporting ability of the device was enhanced by using the Bphen: CsN3 doped electron transport layer. As a result, the turn-on voltage was decreased, and the brightness and the luminous efficiency of the device were improved.The optimal doping concentration of the device was 10%.The device shows a turn-on voltage of 2.3 V and the maximum luminance reaches 29 060 cd/m2 at 7.2 V, more than 2.5 times of that of the device without doping. The maximum current efficiency was 3.27 cd/A when the voltage was 6.6 V.When the doping concentration further increases,the efficiency of the device is decreased owning to Cs atom quenching the luminescence center induced by interdiffusion.

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于瑶瑶, 陈星明, 金玉, 吴志军, 陈燕. 利用CsN3n型掺杂电子传输层改善OLED器件性能的研究[J]. 液晶与显示, 2016, 31(8): 773. YU Yao-yao, CHEN Xing-ming, JIN Yu, WU Zhi-jun, CHEN Yan. Improved properties of organic light-emitting devices by utilizing CsN3 n-type doped electron transport layer[J]. Chinese Journal of Liquid Crystals and Displays, 2016, 31(8): 773.

利用CsN3n型掺杂电子传输层改善OLED器件性能的研究

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