White electrophosphorescence from semiconducting polymer blends

White emission from polymer light-emitting diodes (PLEDs) is demonstrated using semiconducting polymers blended with organometallic emitters and spin-cast from solution. Because a single semiconducting polymer was used as the common host for red, green, and blue emission, the color coordinates, color temperatures, and color rendering indices of the white emission are insensitive to the brightness, applied voltage, and applied current density. The PLEDs have luminous efficiency of 4.3 cd A(-1) and luminance of 223 cd m(-2) at current density of 5.2 mA cm(-2) (V = 14 V): at 17 V, L = 1.2 x 10(4) cd m(-2).