Search

White phosphorescent light emission from polymer light-emitting devices (PLEDs) has been demonstrated. To fabricate the white-emitting PLED, blue phosphorescent polymer (BPP) and red phosphorescent polymer (RPP) were used for the emissive layer, and the emission color was tuned by controlling the concentration ratio of BPP to RPP. The external quantum efficiency of the white-emitting PLED, with CIE coordinates of (0.34, 0.36), was 6.0% at luminance of 100 cd/m2. To investigate the emission mechanism in the PLED, its photoluminescence spectrum and transient decay were measured. These experimental measurements indicate that direct excitation of the iridium-complex (Ir-complex) units by carrier trapping is a major excitation process for white-emitting PLED. A 3.6-in full-color display based on the white phosphorescent PLED and color filters was demonstrated. [ABSTRACT FROM PUBLISHER]

Abstract: The white light emitting diode based on small molecules, which have double emitting layers, was fabricated by combining a solution process and a vacuum deposition process. The organic light emitting diode that we have prepared utilizes a three phosphorescent guest materials, iridium(III)bis(4′,6′-difluorophenylpyridinato)tetrakis(1-pyrazolyl)borate, fac tris(2-phenylpyridine) iridium (III) and tris[1-phenylisoquinolinato-C2,N] iridium (III), exhibits a high color rendering index of over 82. Despite its ease of fabrication, the peak power efficiency was about 16lm/W. The high efficiency was attributed to the distribution of the emitting region over the two emitting layers, which is caused by energy transfer between the phosphorescent guests. [Copyright &y& Elsevier]