Effect of deposition rate on device performance and lifetime of planar molecule-based organic light-emitting diodes

Electrical and optical characteristics, surface morphology and device lifetime of planar molecule bis(10-hydroxybenzo[h]qinolinato) beryllium (Bebq(2)) were studied as a function of the deposition rate. These devices exhibited a significant decrease in the photoluminescence (PL) efficiency due to the formation of large aggregation in the emitting layer during a slower deposition process. Time-of-flight studies showed that the molecule-packing configuration in the ordered aggregates could enhance the probability for site-to-site hopping via intermolecular interactions. The effects of the deposition rate on the device performance of an organic light-emitting diode were exhaustively analysed by examining the electrical property, morphology, PL decay and device simulation. These results provide valuable insights into the effects of varying deposition rates on the electroluminescence efficiency and device reliability.