A non-planar pentaphenylbenzene functionalized benzo[2,1,3]thiadiazole derivative as a novel red molecular emitter for non-doped organic light-emitting diodes

摘要

A novel non-planar pentaphenylbenzene functionalized benzo[2,1,3]thiadiazole derivative(BPTBTD)has been designed and synthesized with only three steps,and applied into non-doped organic light-emitting diodes(OLEDs)as a red molecular emitter.The molecule exhibits good solubility in common organic solvents,excellent thermal stability and film-forming properties.The most important feature is that photoluminescence of BPTBTD shows excellent stablity in different solvents,at different concentrations and in different solid states.Red organic light-emitting diodes were fabricated in a facile non-doped configuration with different thicknesses of emission layers.Saturated red-emission was observed with an emission peak at 621 nm,a maximum external quantum efficiency of 1.0% and a maximum brightness of 1572 cd m~(-2).Especially,the properties of devices with thick emission layers are two times better than those of the devices with thin emission layers.These results indicate that the non-planar pentaphenylphenyl functional groups substantially suppressed the tendency for molecular aggregation in thin solid films,leading to a very stable photoluminescence and higher efficiency of devices with thicker layers.