Symmetrical Emission Transparent Organic Light-Emitting Diodes With Ultrathin Ag Electrodes

IEEE Photonics Journal

Juyoung Ham¹  Illhwan Lee¹  Hyung Won Cho¹  Sungjun Kim¹  Jae Yong Park¹  Seungo Gim¹  Kihyon Hong¹  Kisoo Kim¹  Jong-Lam Lee¹  Sungjoo Kim¹ 

[1] Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, South Korea;

关键词: Organic light-emitting diode;    transparent;    ultra-thin;    bi-directional;    micro-cavity.;   

DOI  :  10.1109/JPHOT.2018.2823759

来源: DOAJ

【 摘 要 】

This paper describes a way to implement a transparent electrode for symmetrical emission from the bottom and top sides of transparent organic light-emitting diodes (TOLEDs). An ultrathin (~6 nm) and smooth Ag film was achieved by using the pretreatment of using oxygen plasma prior to deposition of a nanoscale-thin Ag film on glass. The treatment increased the surface energy, thereby enhancing the wettability of the Ag on glass substrate and consequently leading to the formation of thin and unifrom Ag film with high optical transmittance T ~ 76% and low sheet resistance RS <; 15 Ω □^-1. Using this scheme, a highly transparent glass/Ag/WO3 structure with T = 85.6%, and RS = 9.3 Ω □^-1 was designed (ITO: 83.1%, 10 Ω □^-1). We conducted finite-domain time-difference simulation for this glass/Ag/WO3 electrode to design a weak microcavity structure that retained the transparency and emitting properties. This optimized structure of TOLEDs (Ag = 6 nm) showed higher T = 73.84% than those of ITO devices (T = 73.19%), and can induce the weak microcavity effect, resuting in improved electroluminescent properties and increased the luminance value from 38.25 to 56.25 cd A^-1 at 25 mA cm^-2.

【 授权许可】

Unknown