High-contrast top-emitting organic light-emitting devices

Abstract

In this paper we report on a high-contrast top-emitting organic light-emitting device utilizing a moderate-reflection contrast-enhancement stack and a high refractive index anti-reflection layer. The contrast-enhancement stack consists of a thin metal anode layer, a dielectric bilayer, and a thick metal underlayer. The resulting device, with the optimized contrast-enhancement stack thicknesses of Ni (30 nm)/MgF2 (62 nm)/ZnS (16 nm)/Ni (20 nm) and the 25-nm-thick ZnS anti-reflection layer, achieves a luminous reflectance of 4.01% in the visible region and a maximum current efficiency of 0.99 cd/A (at 62.3 mA/cm2) together with a very stable chromaticity. The contrast ratio reaches 561:1 at an on-state brightness of 1000 cd/m2 under an ambient illumination of 140 lx. In addition, the anti-reflection layer can also enhance the transmissivity of the cathode and improve light out-coupling by the effective restraint of microcavity effects.

Multi-polar resistance switching and memory effect in copper phthalocyanine junctions

“…Organic materials, because of the advantages such as low cost fabrication, printability, high mechanical flexibility, and environment friendly, are being successfully used in organic light-emitting display (OLED), field effect transistor and solar cell fields. [1][2][3][4][5][6] Recently, the organic memory devices have inspired more and more attention for their potential use in substituting inorganic ones to satisfy the demand for inexpensive and high density data storage media. [7][8][9][10][11][12][13][14][15] Many organic materials including small molecular and polymer have achieved the memory effect.…”