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Ligand-engineered bandgap stability in mixed-halide perovskite LEDs
Yasser Hassan1, Jong Hyun Park2, Michael L Crawford3
1Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK. yasserhassan8085@gmail.com.
Nature
|March 4, 2021
Summary
Researchers developed multidentate ligands to stabilize red light emission from lead halide perovskites. This method prevents halide segregation, enabling efficient and color-stable red light-emitting diodes.
Area of Science:
- Materials Science
- Solid-State Physics
- Optoelectronics
Background:
- Lead halide perovskites offer bright, tunable luminescence for light-emitting applications.
- High efficiencies have been achieved, but stable red emission remains a challenge due to halide segregation.
Purpose of the Study:
- To develop a method for achieving efficient and color-stable red electroluminescence from mixed-halide perovskites.
- To suppress halide segregation in perovskite nanocrystals during operation.
Main Methods:
- Treatment of mixed-halide perovskite nanocrystals with multidentate ligands.
- Electroluminescence measurements.
- Density functional theory calculations.
Main Results:
- Demonstrated color-stable red emission at 620 nm with 20.3% external quantum efficiency.
- Ligand treatment removed lead atoms from the nanocrystal surface.
- Ligand binding suppressed iodine Frenkel defects, inhibiting halide segregation.
Conclusions:
- Multidentate ligand treatment is effective in stabilizing red electroluminescence from mixed-halide perovskites.
- Controlling surface defects is crucial for bandgap stability in perovskite optoelectronics.
- This approach has implications for improving light-emitting diodes and potentially photovoltaics.
