Effect of Al:Ag alloy cathode on the performance of transparent organic light-emitting devices

• 来源期刊: 光电子快报（英文版）
• 年，卷（期）: 2017,（3）
• 页码范围: 175-178
• 页数: 4页
• 语种: 英文
• DOI: 10.1007/s11801-017-7039-0

摘要

Transparent organic light-emitting devices (TOLEDs) based on a stacked alloy cathode of LiF/Al:Ag are investigated.The devices have a structure of indium-tin-oxide (ITO)/4,4',4"-Tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA) (25 nm)/N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-l,l'-biphenyl-4,4'-diamine (NPB) (40 nm)/tris-(8-hydroxyquinoline) aluminum (Alq3) (50 nm)/LiF (1 nm)/Al:Ag (1:3) (x),where the thicknesses of cathode metal layers (Al:Ag) are adjusted,respectively,from 70 nm to 100 nm.In the experiment,it is found that the LiF (1 nm)/Al:Ag (1:3) (75 nm) has good electron injection efficiency.Compared with an Al-only cathode,the turn-on voltage is lowered.At the voltage of 10 V,the luminances for bottom emission from ITO anode side and top emission from metal cathode side are 2 459 cd/m2 and 1 729 cd/m2,respectively.Thanks to electron injection enhancement by using Al:Ag cathode,we can obtain a better energy level matching between the cathode and the organic layer,thus the devices have lower turn-on voltage and higher luminance.The total transmittance of the devices can achieve about 40％ at the wavelength of 550 nm.