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Electrochemically Stable Ligands of ZnO Electron-Transporting Layers for Quantum-Dot Light-Emitting Diodes.

Desui ChenLuying MaYunhua ChenXiaoqi ZhouShiyu XingYunzhou DengYanlei HaoChao-Dan PuKangren KongYizheng Jin
Published in: Nano letters (2023)
Thin films of ZnO nanocrystals are actively pursued as electron-transporting layers (ETLs) in quantum-dot light-emitting diodes (QLEDs). However, the developments of ZnO-based ETLs are highly engineering oriented and the design of ZnO-based ETLs remains empirical. Here, we identified a previously overlooked efficiency-loss channel associated with the ZnO-based ETLs: i.e., interfacial exciton quenching induced by surface-bound ethanol. Accordingly, we developed a general surface-treatment procedure to replace the redox-active surface-bound ethanol with electrochemically inert alkali carboxylates. Characterization results show that the surface treatment procedure does not change other key properties of the ETLs, such as the conductance and work function. Our single-variable experimental design unambiguously demonstrates that improving the electrochemical stabilities of the ZnO ETLs leads to QLEDs with a higher efficiency and longer operational lifetime. Our work provides a crucial guideline to design ZnO-based ETLs for optoelectronic devices.
Keyphrases
  • room temperature
  • quantum dots
  • reduced graphene oxide
  • visible light
  • ionic liquid
  • light emitting
  • energy transfer
  • minimally invasive
  • solar cells
  • high resolution
  • molecularly imprinted
  • tandem mass spectrometry