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NIR Luminescence from Deep-Level Traps in CsPbBr3 Microcrystals
Jonathan Vandenwijngaerden1, Bapi Pradhan1, Bob Van Hout1
1Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium.
The Journal of Physical Chemistry Letters
|March 31, 2025
Summary
Researchers observed near-infrared (NIR) emission in cesium lead halide perovskite microcrystals. This emission originates from deep trap states, revealing new insights into perovskite recombination pathways.
Area of Science:
- Materials Science
- Solid State Physics
- Optoelectronics
Background:
- All-inorganic perovskites like CsPbBr3 and CsPb(Br/Cl)3 are promising optoelectronic materials.
- Understanding their excited-state dynamics and emission properties is crucial for device applications.
Purpose of the Study:
- To report the first observation of near-infrared (NIR) emission in CsPbBr3 and CsPb(Br/Cl)3 perovskite microcrystals.
- To investigate the origin and characteristics of this NIR emission.
- To quantitatively determine the quantum yield and dynamics of this emission pathway.
Main Methods:
- Temperature- and power-dependent NIR and visible luminescence spectroscopy.
- Time-resolved luminescence spectroscopy (picosecond-to-nanosecond timescale).
Main Results:
- Observation of a broadband NIR emission band in CsPbBr3 and CsPb(Br/Cl)3 microcrystals.
- Demonstration that NIR emission arises from radiative transitions involving deep trap states.
- Quantitative determination of the deep trap emission quantum yield (~0.3% at room temperature).
- Observation of NIR state population on a 660 ps timescale, consistent with carrier capture by deep traps.
Conclusions:
- Deep trap states contribute to radiative recombination in metal halide perovskite microcrystals.
- This study reveals previously unexplored recombination channels in these materials.
- The findings enhance the fundamental understanding of perovskite photophysics and potential applications.
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