Fast Near-Infrared Photodetectors Based on Nontoxic and Solution-Processable AgBiS2

Yi Teng Huang, Davide Nodari, Francesco Furlan, Youcheng Zhang, Marin Rusu, Linjie Dai, Zahra Andaji-Garmaroudi, Daniel Darvill, Xiaoyu Guo, Martina Rimmele, Thomas Unold, Martin Heeney, Samuel D. Stranks, Henning Sirringhaus, Akshay Rao, Nicola Gasparini*, Robert L.Z. Hoye*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Solution-processable near-infrared (NIR) photodetectors are urgently needed for a wide range of next-generation electronics, including sensors, optical communications and bioimaging. However, it is rare to find photodetectors with >300 kHz cut-off frequencies, especially in the NIR region, and many of the emerging inorganic materials explored are comprised of toxic elements, such as lead. Herein, solution-processed AgBiS2 photodetectors with high cut-off frequencies under both white light (>1 MHz) and NIR (approaching 500 kHz) illumination are developed. These high cut-off frequencies are due to the short transit distances of charge-carriers in the ultrathin photoactive layer of AgBiS2 photodetectors, which arise from the strong light absorption of this material, such that film thicknesses well below 120 nm are sufficient to absorb >65% of NIR to visible light. It is also revealed that ion migration plays a critical role in the photo-response speed of these devices, and its detrimental effects can be mitigated by finely tuning the thickness of the photoactive layer, which is important for achieving low dark current densities as well. These outstanding characteristics enable the realization of air-stable, real-time heartbeat sensors based on NIR AgBiS2 photodetectors, which strongly motivates their future integration in high-throughput systems.

Original languageEnglish (US)
Article number2310199
JournalSmall
Volume20
Issue number18
DOIs
StateAccepted/In press - 2023

Keywords

  • AgBiS
  • cut-off frequency
  • heart-beat sensors
  • near-infrared photodetectors
  • solution-processable electronics
  • ultrathin absorbers

ASJC Scopus subject areas

  • Biotechnology
  • General Chemistry
  • Biomaterials
  • General Materials Science
  • Engineering (miscellaneous)

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