Ultrafast carrier dynamics in BiVO4: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations

Benjamin J. Dringoli; Keith T. Butler; Lite Zhou; Binod Giri; Pratap M. Rao; A. Walsh; Lyubov V. Titova

doi:10.1109/IRMMW-THz.2016.7758784

Ultrafast carrier dynamics in BiVO₄: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations

Benjamin J. Dringoli
, Keith T. Butler
, Lite Zhou
, Binod Giri
, Pratap M. Rao
, A. Walsh
, Lyubov V. Titova

Department of Physics

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

1 Scopus citations

Abstract

BiVO₄ is a promising material for solar energy conversion applications. However, it suffers from low mobility due to strong carrier-phonon coupling, which favors formation of polarons. To elucidate carrier transport mechanisms in BiVO₄, we apply time-resolved THz spectroscopy to probe dynamics of photexcited carriers and their coupling to lattice vibrational modes at early times (1-20 ps) after photoexcitation. We find that at high excitation fluences, trap states are saturated and a short-lived population of highly mobile residual carriers exists. At the same time, saturation of hole trap states manifests itself in changes in the low-frequency (1.92 THz) seesaw phonon mode between the Bi and VO₄ units.

Original language	English
Title of host publication	41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016
Publisher	IEEE Computer Society
ISBN (Electronic)	9781467384858
DOIs	https://doi.org/10.1109/IRMMW-THz.2016.7758784
State	Published - 28 Nov 2016
Event	41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016 - Copenhagen, Denmark Duration: 25 Sep 2016 → 30 Sep 2016

Publication series

Name	International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz
Volume	2016-November
ISSN (Print)	2162-2027
ISSN (Electronic)	2162-2035

Conference

Conference	41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016
Country/Territory	Denmark
City	Copenhagen
Period	25/09/16 → 30/09/16

Bibliographical note

Publisher Copyright:
© 2016 IEEE.

Access to Document

10.1109/IRMMW-THz.2016.7758784

Cite this

Dringoli, B. J., Butler, K. T., Zhou, L., Giri, B., Rao, P. M., Walsh, A., & Titova, L. V. (2016). Ultrafast carrier dynamics in BiVO₄: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations. In 41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016 Article 7758784 (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz; Vol. 2016-November). IEEE Computer Society. https://doi.org/10.1109/IRMMW-THz.2016.7758784

Dringoli, Benjamin J. ; Butler, Keith T. ; Zhou, Lite et al. / Ultrafast carrier dynamics in BiVO₄ : Interplay between free carriers, trapped carriers and low-frequency lattice vibrations. 41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016. IEEE Computer Society, 2016. (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz).

@inproceedings{09e0fa1abae244399e804eec7e2fa5dd,

title = "Ultrafast carrier dynamics in BiVO4: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations",

abstract = "BiVO4 is a promising material for solar energy conversion applications. However, it suffers from low mobility due to strong carrier-phonon coupling, which favors formation of polarons. To elucidate carrier transport mechanisms in BiVO4, we apply time-resolved THz spectroscopy to probe dynamics of photexcited carriers and their coupling to lattice vibrational modes at early times (1-20 ps) after photoexcitation. We find that at high excitation fluences, trap states are saturated and a short-lived population of highly mobile residual carriers exists. At the same time, saturation of hole trap states manifests itself in changes in the low-frequency (1.92 THz) seesaw phonon mode between the Bi and VO4 units.",

author = "Dringoli, \{Benjamin J.\} and Butler, \{Keith T.\} and Lite Zhou and Binod Giri and Rao, \{Pratap M.\} and A. Walsh and Titova, \{Lyubov V.\}",

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Dringoli, BJ, Butler, KT, Zhou, L, Giri, B, Rao, PM, Walsh, A & Titova, LV 2016, Ultrafast carrier dynamics in BiVO₄: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations. in 41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016., 7758784, International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, vol. 2016-November, IEEE Computer Society, 41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016, Copenhagen, Denmark, 25/09/16. https://doi.org/10.1109/IRMMW-THz.2016.7758784

Ultrafast carrier dynamics in BiVO₄: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations. / Dringoli, Benjamin J.; Butler, Keith T.; Zhou, Lite et al.
41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016. IEEE Computer Society, 2016. 7758784 (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz; Vol. 2016-November).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - Dringoli, Benjamin J.

AU - Butler, Keith T.

AU - Zhou, Lite

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AU - Rao, Pratap M.

AU - Walsh, A.

AU - Titova, Lyubov V.

PY - 2016/11/28

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N2 - BiVO4 is a promising material for solar energy conversion applications. However, it suffers from low mobility due to strong carrier-phonon coupling, which favors formation of polarons. To elucidate carrier transport mechanisms in BiVO4, we apply time-resolved THz spectroscopy to probe dynamics of photexcited carriers and their coupling to lattice vibrational modes at early times (1-20 ps) after photoexcitation. We find that at high excitation fluences, trap states are saturated and a short-lived population of highly mobile residual carriers exists. At the same time, saturation of hole trap states manifests itself in changes in the low-frequency (1.92 THz) seesaw phonon mode between the Bi and VO4 units.

AB - BiVO4 is a promising material for solar energy conversion applications. However, it suffers from low mobility due to strong carrier-phonon coupling, which favors formation of polarons. To elucidate carrier transport mechanisms in BiVO4, we apply time-resolved THz spectroscopy to probe dynamics of photexcited carriers and their coupling to lattice vibrational modes at early times (1-20 ps) after photoexcitation. We find that at high excitation fluences, trap states are saturated and a short-lived population of highly mobile residual carriers exists. At the same time, saturation of hole trap states manifests itself in changes in the low-frequency (1.92 THz) seesaw phonon mode between the Bi and VO4 units.

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Dringoli BJ, Butler KT, Zhou L, Giri B, Rao PM, Walsh A et al. Ultrafast carrier dynamics in BiVO₄: Interplay between free carriers, trapped carriers and low-frequency lattice vibrations. In 41st International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2016. IEEE Computer Society. 2016. 7758784. (International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz). doi: 10.1109/IRMMW-THz.2016.7758784