Fabrication of hybrid white OLEDs with an inorganic color conversion layer

We report hybrid white organic light-emitting diodes (WOLEDs) made by combining FIrpic-based blue-emitting OLEDs and a printable red-emitting inorganic phosphor. The color conversion can be easily controlled by adjusting the thickness of the red phosphor. FIrpic-based phosphorescent OLEDs, with a 15-m-thick phosphor layer, show warm white light emission leading to a current efficiency of 11.4cd/A, a power efficiency of 4.9lm/W, and a CIE coordinate of (0.33, 0.41) at a luminance of 1000cd/m(2). Moreover, the output spectra and CIE coordinates of the WOLED show no significant change over a wide range of current densities.