The authors have developed a semitransparent, multilayered cathode of indium tin oxide (ITO)/Ag/tungsten oxide (W O3) for transparent organic light-emitting diodes. The device showed a weak negative differential resistance (NDR), until the operating voltage of 8 V was reached. NDR was due to the resonant tunneling by both the quantum barrier and quantum well. The silver oxide (Ag2 O) on the Ag metal was confirmed by x-ray photoelectron spectroscopy, and the energy levels of Ag2 O were quantized due to the quantum size effect and this produced the resonant tunneling channels. The device using ITOAgW O3 with a LiFAl bilayer was superior to those devices which only used ITO or W O3, mainly because the out coupling was enhanced by employing a W O3 material, which is much more transparent than ITO.
Bibliographical noteFunding Information:
The authors offer special thanks to Professor Jun Yeob Lee from Dankook University for his valuable advice. This work was supported by the Brain Korea 21 (BK21) fellowship program at Korea’s Ministry of Education.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)