Highly mobile hot holes in Cs<sub>2</sub>AgBiBr<sub>6</sub> double perovskite.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34936431.
- Also identified by DOI 10.1126/sciadv.abj9066 and PMC identifier 8694595.
- Licence recorded as CC BY-NC.
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Abstract
Highly mobile hot charge carriers are a prerequisite for efficient hot carrier optoelectronics requiring long-range hot carrier transport. However, hot carriers are typically much less mobile than cold ones because of carrier-phonon scattering. Here, we report enhanced hot carrier mobility in Cs<sub>2</sub>AgBiBr<sub>6</sub> double perovskite. Following photoexcitation, hot carriers generated with excess energy exhibit boosted mobility, reaching an up to fourfold enhancement compared to cold carriers and a long-range hot carrier transport length beyond 200 nm. By optical pump–infrared push-terahertz probe spectroscopy and frequency-resolved photoconductivity measurements, we provide evidence that the conductivity enhancement originates primarily from hot holes with reduced momentum scattering. We rationalize our observation by considering (quasi-)ballistic transport of thermalized hot holes with energies above an energetic threshold in Cs<sub>2</sub>AgBiBr<sub>6</sub>. Our findings render Cs<sub>2</sub>AgBiBr<sub>6</sub> as a fascinating platform for studying the fundamentals of hot carrier transport and its exploitation toward hot carrier–based optoelectronic devices.