Brightness degradation and its mechanism in Tb‐doped ZnS thin‐film electroluminescent devices

摘要

We investigated the origin and mechanism of brightness degradation in Tb‐doped ZnS thin‐film green electroluminescent devices. We concluded that the increased number of TbF bond breaking, acting as nonradiative emission centers for Tb emission, is responsible for the degradation. The recombination energy of electron‐hole pairs generated by hot‐electron impact at the Tb‐doping site breaks the TbF bond, which is vital to efficiency. We found that high‐temperature annealing reduces the generation rate of nonradiative recombination centers, resulting in long device life.