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Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
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Ultrafast Excited-State Localization in Cs2AgBiBr6 Double Perovskite
Adam D Wright1, Leonardo R V Buizza1, Kimberley J Savill1
1Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
The Journal of Physical Chemistry Letters
|March 30, 2021
Summary
Lead-free Cs2AgBiBr6 perovskites show rapid charge carrier localization. Ultrafast, barrier-free trapping to polaronic states occurs within 1.0 ps, impacting photovoltaic device efficiency.
Area of Science:
- Materials Science
- Solid State Physics
- Photovoltaics
Background:
- Cesium silver bismuth bromide (Cs2AgBiBr6) is a lead-free double perovskite with potential for efficient solar cells.
- Understanding charge carrier dynamics is crucial for optimizing photovoltaic performance.
Purpose of the Study:
- Investigate the behavior of photoexcited charge carriers in Cs2AgBiBr6.
- Elucidate the mechanisms of charge carrier localization and transport.
Main Methods:
- Temperature-dependent photoluminescence spectroscopy
- Absorption spectroscopy
- Optical pump-terahertz probe spectroscopy
Main Results:
- Observed ultrafast, barrier-free localization of free carriers to small polaronic states within 1.0 ps.
- Delocalized carriers exhibited bandlike transport, while self-trapped polarons showed temperature-activated mobility (>1 cm2 V-1 s-1 at room temperature).
- Strong electron-phonon coupling was identified as the driver for rapid charge carrier localization.
Conclusions:
- Charge carrier localization significantly influences carrier dynamics in Cs2AgBiBr6.
- The material's properties suggest potential challenges and opportunities for photovoltaic applications.
- Further research into electron-phonon coupling is warranted for material optimization.
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