Influence of the Charge Transfer on the Lifetime of Quantum-Dot Light-Emitting Diodes

The operating lifetime of quantum-dot light-emitting diodes (QLEDs) is a critical parameter for quantum-dot display which is becoming an emerging display technology. To pinpoint the causes of device degradation, we demonstrated an enhanced reliability of all-solution processed QLEDs by introducing an insulating interfacial layer between the ETL and the QDs. It is confirmed that a PMMA interfacial layer can delay the electron transfer and reduce the nonradiative recombination, which in turn slow down the degradation of QDs-ZnO layer. In comparison with the standard QLEDs, device fabricated with PMMA of 1.0 mg/ml shows longest lifetime of 28.7h, which improves the lifetime by 50%. We studied the effect of electrons transfer on the degradation mechanisms, which lays the foundation for further improvement of the device life.