White Electroluminescence with Simultaneous Three-Color Emission from a Four-Armed Star-Shaped Single-Polymer System

A four-armed star-shaped single-polymer system with 4,7-bis(5-(4-(9H-carbazol-9-yl)phenyl)-4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (FTBT) as a red emissive core, polyfluorene (PF) as blue emissive arms and 1,3-benzo thiadiazole (BT) as green emissive dopants was designed and synthesized, in which red, green, and blue (RGB) emission balance can be achieved by adjusting the doping concentration of FTBT and BT discreetly. A typical single-emissive-layer device (ITO/PEDOT:PSS/polymer/TPBI/LiF/Al) was studied and discussed, realizing a pure and stable white emission with a luminous efficiency (LE) of 1.59 cd·A^-1 and CIE coordinates of (0.31, 0.34). The high-color-quality white electroluminescence of the devices could be mainly attributed to the suppressed intermolecular interactions, and partial energy transfer from the blue PF arms to the red and green dopants. A four-armed star-shaped single-polymer system with simultaneous red, green, and blue (RGB) emission was designed and synthesized, which realized pure and stable white emission with a luminous efficiency (LE) of 1.59 cd·A^-1 and CIE coordinates of (0.31, 0.34) in a typical single-emissive-layer device.