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Highly Transparent and Flexible Organic Light‐Emitting Diodes with Structure Optimized for Anode/Cathode Multilayer Electrodes
Author(s) -
Kim DongYoung,
Han Yun Cheol,
Kim Hyun Cheol,
Jeong Eun Gyo,
Choi Kyung Cheol
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502542
Subject(s) - materials science , cathode , anode , oled , transmittance , optoelectronics , electrode , layer (electronics) , substrate (aquarium) , polyethylene terephthalate , dielectric , diode , fabrication , nanotechnology , composite material , chemistry , medicine , oceanography , alternative medicine , pathology , geology
In this study, a dielectric layer/metal/dielectric layer (multilayer) electrode is proposed as both anode and cathode for use in the fabrication of transparent and flexible organic light‐emitting diodes (TFOLEDs). The structure of multilayer electrodes is optimized by systematic experiments and optical calculations considering the transmittance and efficiency of the device. The details of the multilayer electrode structure are [ZnS (24 nm)/Ag (7 nm)/MoO 3 (5 nm)] and [ZnS (3 nm)/Cs 2 CO 3 (1 nm)/Ag (8 nm)/ZnS (22 nm)], as anode and cathode, respectively. The optimized TFOLED design is fabricated on a polyethylene terephthalate (PET) substrate, and the device shows high transmittance (74.22% around 550 nm) although the PET substrate has lower transmittance than glass. The TFOLEDs operate normally under compressive stress; degradation of electrical characteristics is not observed, comparable to conventional OLEDs with ITO and Al as electrodes. In addition, because the fabricated TFOLEDs show a nearly Lambertian emission pattern and a negligible shift of Commission International de l'Eclairage (CIE) coordination, it is concluded that the fabricated TFOLEDs are suitable for use in displays.