Full-wavelength white organic light emitting diodes with blue fluorescence and phosphorescent iridium complexes

Abstract

A highly efficient white organic light emitting diode (WOLED) was fabricated and possible emission mechanisms of a WOLED configured with blue fluorescence and phosphorescent iridium complexes are proposed. The white light emitting layer is comprised of a blue fluorescent emitting layer anthracene and a green and red phosphorescent emitting layer TPBI:11% Ir(ppy)(3): 0.5% Ir(piq)(2)(acac). The device exhibits white emission with a Commission Internationale de l'Eclairage coordinate of (x = 0.33, y = 0.33) and the luminance and luminous efficiency was 6389 cd/m(2) and 6.4 cd/A, respectively, at 100 mA/cm(2). Evidence indicates that the good energy overlap between the absorption spectrum of Ir(ppy)(3) and Ir(piq)(2)(acac) and the emission spectrum of TPBI results in an effective energy transfer from TPBI to Ir(ppy)(3) and Ir(piq)(2)(acac). The optimal thickness of the green and red emitting layer promotes the injection and emitting of carriers in that layer. (c) 2006 The Electrochemical Society.