White-Light-Emitting Material for Organic Electroluminescent Devices

Abstract

White emission is important for applying organic EL devices to full-color displays and backlighting. In order to obtain white emission, the use of a white-light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A device structure of indium-tin-oxide (ITO, anode)/hole transport layer/emitting layer/MgIn alloy (cathode) was employed. Bis(2-(2-hydroxyphenyl)benzothiazolate)zinc ( Zn(BTZ) 2 ) was used as the emitting material. Zn(BTZ) 2 showed greenish-white emission with a broad electroluminescent spectrum (half-width: 157 nm, peak wavelength: 486, 524 nm). It exhibited a high luminance of 10,190 cd/m 2 at the applied voltage of 8 V because Zn(BTZ) 2 has a good electron-transport property. As such, Zn(BTZ) 2 is expected to serve as a new white-light-emitting material for organic EL devices.