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。

Improved properties of organic light-emitting devices by utilizing CsN3 n-type doped electron transport layer

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.