ZHONG Jian, GAO Zhuo, YU Junsheng^*, and JIANG Yadong

State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610064, P. R. China

(Received September 8, 2010; Accepted November 5, 2010)

A green organic light-emitting diodes (OLED) with a multilayer structure of indium–tin oxide (ITO)/copper-phthalocyanine (CuPc) (200 Å)/N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (α-NPD) (600 Å)/N'-diphenyl-N,N'-tris(8-hydroxyquinoline) aluminium (Alq₃) (400 Å):10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-(l)benzopyropyrano(6,7,8-i, j)quinolizin-11-one (C545T) (2%)/Alq₃ (200 Å)/LiF (10 Å)/Al (1000 Å) was prepared via vacuum thermal evaporation. To reduce the impact of water vapor and oxygen on the device, we encapsulated it with a kind of specific and efficient desiccant, called DESIPASTE, under the protection of high-purity nitrogen. By analyzing a series of optical characteristics of OLEDs, the results showed that this desiccant can improve the brightness about 500 and 250 cd/m² at same driving voltage and current density, respectively. The electroluminescent (EL) spectra were hardly affected except a very weak blue shift of broadband emission peak. It turns out that encapsulation with DESIPASTE is a simple and efficient way to improve the performance of OLED.

Key words: organic light-emitting diode (OLED), desiccant, vapor permeation, degradation

^*E-mail address: jsyu@uestc.edu.cn