Full-color displays of passive-matrix driven organic electroluminescence panels

Abstract

2.2 inch diagonal full-color passive-matrix displays of organic electroluminescence panels were fabricated, and the possibility of mass production was examined. The panel consisted of 132 x 162 pixels, and each pixel had three subpixels of red, green and blue emission in line. The panel contained stripe-shaped ITO lines, multi layers of organic materials, and cathode lines orthogonal to ITO lines. The organic layers of the electroluminescence panels were fabricated by vacuum evaporation method. Full-color emission was performed by patterning directly the emitting layers of red, green and blue color through metal mask in order to take most advantage of the luminous efficiency of electroluminescence. Pixel size of 0.272 mm x 0.264 mm was performed by vacuum evaporation using metal mask. This simple-structured panel was driven with passive matrix drive method. Dual scan drive method was adopted to lower the duty ratio, which made the peak luminance lower. Total thickness of the module was only 2.5 mm. We started pilot production of the 2.2 inch diagonal full-color organic electroluminescence panels, and good manufacturability is promised.

Studies of kinetics of charge carrier recombination in organic light-emitting diodes based on beryllium complexes by transient electroluminescence

“…The values of slopes (S) and intercepts (A) were obtained to be S = 4.72 × 10 6 and A = 4.15 for Bepp 2 -based device, and S = 6.70 × 10 6 and A = 7.95 for Betp 2 -based device. The electron-hole recombination coefficient of the Bepp 2 , calculated using equation(7) with j = 0.17 A cm −2 and L = 60 nm, is γ = 7.3 × 10 −12 cm 3 s −1 , which is approximately two times larger than the value of 4.0×10 −12 cm 3 s −1 for Betp 2 . The higher recombination coefficient agrees with the higher EL efficiency in Bepp 2 -based devices than that in Betp 2 -based devices.…”

“…Since the first observation of efficient bright emission from a triphenylamine derivative/tris(8-hydroxyquinoline) aluminium (Alq 3 ) double-layer structure [1], organic lightemitting diodes (OLEDs) have been extensively studied for their possible applications in the lighting industry, especially in full colour displays [2][3][4][5][6][7][8]. In OLEDs, the electronic processes including the charge-carrier injection, charge-carrier transport, charge-carrier recombination and the radiative decay of the excited state play important roles in the performance of OLEDs.…”