---
_id: '66036'
abstract:
- lang: eng
  text: Light-assisted metal oxide-based chemiresistive gas sensors are widely explored
    for operation at relatively low temperatures, yet the investigation of the role
    of irradiance, as opposed to wavelength, remains underrepresented. Here, we systematically
    quantify the irradiance-dependent behavior of ordered mesoporous In2O3 under visible
    light illumination. Photoconductivity measurements reveal two distinct irradiance
    regimes consistent with trap-limited transport at low power and recombination-
    or saturation-limited transport at high power. Gas sensing experiments towards
    CO and H2 show a pronounced non-monotonic response, reaching maximum responses
    of 0.74 for 135 ppm CO at 67 mW cm−2 and 0.64 for 90 ppm H2 at 11 mW cm−2, followed
    by strong suppression at higher irradiance. Illumination also accelerated the
    response kinetics. At 60 ppm, t90 decreases from 96 to 12 s for CO and 141 to
    27 s for H2, corresponding to an 8- and 5-fold faster response time, respectively.
    Near-ambient pressure-XPS under controlled atmosphere and density functional theory
    calculations indicate defect-mediated excitation. Oxygen vacancy states and illumination-induced
    modification of surface oxygen species govern this behavior. The results establish
    irradiance as a critical mechanistic parameter that determines whether In2O3 operates
    in a surface-controlled or bulk photoconductive regime. These findings highlight
    the need to explicitly optimize and report irradiance in illuminated gas sensor
    studies, and not only the power consumption of the light source.
article_number: acssensors.6c01100
article_type: original
author:
- first_name: Sven
  full_name: Voth, Sven
  last_name: Voth
- first_name: Zhenyu
  full_name: Zhao, Zhenyu
  last_name: Zhao
- first_name: Dominik
  full_name: Baier, Dominik
  last_name: Baier
- first_name: Alexandra
  full_name: Glass, Alexandra
  last_name: Glass
- first_name: Hossam
  full_name: Elgabarty, Hossam
  id: '60250'
  last_name: Elgabarty
  orcid: 0000-0002-4945-1481
- first_name: Oskar J.
  full_name: Sandberg, Oskar J.
  last_name: Sandberg
- first_name: Guido
  full_name: Grundmeier, Guido
  id: '194'
  last_name: Grundmeier
- first_name: Michael
  full_name: Tiemann, Michael
  id: '23547'
  last_name: Tiemann
  orcid: 0000-0003-1711-2722
- first_name: Jan-Henrik
  full_name: Smått, Jan-Henrik
  last_name: Smått
- first_name: Nicklas
  full_name: Anttu, Nicklas
  last_name: Anttu
- first_name: Teresa
  full_name: de los Arcos, Teresa
  last_name: de los Arcos
- first_name: Christian
  full_name: Weinberger, Christian
  id: '11848'
  last_name: Weinberger
citation:
  ama: 'Voth S, Zhao Z, Baier D, et al. Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas
    Sensors: Why More Light Is Not Always Better. <i>ACS Sensors</i>. Published online
    2026. doi:<a href="https://doi.org/10.1021/acssensors.6c01100">10.1021/acssensors.6c01100</a>'
  apa: 'Voth, S., Zhao, Z., Baier, D., Glass, A., Elgabarty, H., Sandberg, O. J.,
    Grundmeier, G., Tiemann, M., Smått, J.-H., Anttu, N., de los Arcos, T., &#38;
    Weinberger, C. (2026). Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas
    Sensors: Why More Light Is Not Always Better. <i>ACS Sensors</i>, Article acssensors.6c01100.
    <a href="https://doi.org/10.1021/acssensors.6c01100">https://doi.org/10.1021/acssensors.6c01100</a>'
  bibtex: '@article{Voth_Zhao_Baier_Glass_Elgabarty_Sandberg_Grundmeier_Tiemann_Smått_Anttu_et
    al._2026, title={Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas
    Sensors: Why More Light Is Not Always Better}, DOI={<a href="https://doi.org/10.1021/acssensors.6c01100">10.1021/acssensors.6c01100</a>},
    number={acssensors.6c01100}, journal={ACS Sensors}, publisher={American Chemical
    Society (ACS)}, author={Voth, Sven and Zhao, Zhenyu and Baier, Dominik and Glass,
    Alexandra and Elgabarty, Hossam and Sandberg, Oskar J. and Grundmeier, Guido and
    Tiemann, Michael and Smått, Jan-Henrik and Anttu, Nicklas and et al.}, year={2026}
    }'
  chicago: 'Voth, Sven, Zhenyu Zhao, Dominik Baier, Alexandra Glass, Hossam Elgabarty,
    Oskar J. Sandberg, Guido Grundmeier, et al. “Role of Irradiance in Light-Activated
    In<sub>2</sub>O<sub>3</sub>Gas Sensors: Why More Light Is Not Always Better.”
    <i>ACS Sensors</i>, 2026. <a href="https://doi.org/10.1021/acssensors.6c01100">https://doi.org/10.1021/acssensors.6c01100</a>.'
  ieee: 'S. Voth <i>et al.</i>, “Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas
    Sensors: Why More Light Is Not Always Better,” <i>ACS Sensors</i>, Art. no. acssensors.6c01100,
    2026, doi: <a href="https://doi.org/10.1021/acssensors.6c01100">10.1021/acssensors.6c01100</a>.'
  mla: 'Voth, Sven, et al. “Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas
    Sensors: Why More Light Is Not Always Better.” <i>ACS Sensors</i>, acssensors.6c01100,
    American Chemical Society (ACS), 2026, doi:<a href="https://doi.org/10.1021/acssensors.6c01100">10.1021/acssensors.6c01100</a>.'
  short: S. Voth, Z. Zhao, D. Baier, A. Glass, H. Elgabarty, O.J. Sandberg, G. Grundmeier,
    M. Tiemann, J.-H. Smått, N. Anttu, T. de los Arcos, C. Weinberger, ACS Sensors
    (2026).
date_created: 2026-06-24T10:36:11Z
date_updated: 2026-06-24T11:35:36Z
doi: 10.1021/acssensors.6c01100
keyword:
- resistive gas sensing
- indium oxide
- photoactivation
- irradiance
- photoconductivity
- charge carrier dynamics
- oxygen vacancies
language:
- iso: eng
project:
- _id: '1130'
  name: Exploration of optoelectronic properties of metal oxides used in gas sensors
    and solar cells
publication: ACS Sensors
publication_identifier:
  issn:
  - 2379-3694
  - 2379-3694
publication_status: published
publisher: American Chemical Society (ACS)
status: public
title: 'Role of Irradiance in Light-Activated In<sub>2</sub>O<sub>3</sub>Gas Sensors:
  Why More Light Is Not Always Better'
type: journal_article
user_id: '11848'
year: '2026'
...