Metal oxide charge transport materials for light emitting diodes - An overview

As the current era of display world is mostly occupied by solid state light emitting devices (LEDs), research in the development of device structure, fabrication method and performance of the LEDs are the essential fields to be focused. In the case of most promising organic LEDs (OLEDs) as well as rapidly growing quantum dot LEDs (QLEDs) and pervoskite LEDs (PeLEDs), charge transport layers play a crucial role in the improvement of device structure and performance. The chemical stability, thermal stability, charge carrier density, charge carrier mobility, molecular/atomic energy levels and easy processability of the charge transport layers are the important factors that affects the performance and efficiency of LED devices. Compare to the conventionally used organic charge transport materials, inorganic, particularly, metal oxides possessed a satisfactory credential to be a trustworthy material for the application of charge transport layers (CTLs) in organic as well as inorganic LEDs. In the present work, application of metal oxides as hole/electron transport layers, as a better replacement for organic charge transport materials, in different LED architecture and their performance are discussed.