Full-Color Display Realized from a White Polymer Light-Emitting Device Featuring a Modified Buffer Layer and Merged Color Filters

In this study we developed color-stable, broad-spectrum, white polymer light-emitting devices (WPLEDs) featuring glycerol-modified polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene) (G-PEDOT) as the buffer layer and poly(9,9-di-2-adamantylhexylfluorene-2,7-diyl) (PADHF) doped with RP119 as the white emission layer. The optimized WPLED, which had the simple configuration indium tin oxide/G-PEDOT (95 nm, 0.065 g/mL)/PDAHF:2% RP119 (80 nm)/LiF (1 nm)/Ca (10 nm)/Al (200 nm), exhibited a broad-spectrum white emission with a maximum luminance of 16,040 cd/m² at 12.5 V, a maximum current efficiency of 3.46 cd/A at 7 V, and a maximum power efficiency of 1.76 lm/W at 5 V; these values were enhanced by 40, 13, and 14%, respectively, relative to those of the comparable device incorporating unmodified PEDOT. We also realized a full-color display by merging this optimized broad-spectrum WPLED with color filter substrates, obtaining a good color gamut of 53.3%.