White-Light-Emitting Materials for Organic Electroluminescent Devices
White emission is important for applying organic EL devices to full-color flat panel display and backlight for liquid crystal display. In order to obtain white emission, the use of a light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) (Zn(BTZ)2 was known to emit white light with a broad electroluminescence. In this study, the electroluminescent characteristics of Be(BTZ)2 and Mg(BTZ)2, as well as Zn(BTS)2 were investigated using organic electroluminescent devices with the structure of ITO/TPD/ Be(BTZ)2, Mg(BTZ)2, or Zn(BTZ)2/Al. It was found that the device containing Be(BTZ)2 showed the highest power efficiency.