Infrared Organic Photodetectors Employing Ultralow Bandgap Polymer and Non-Fullerene Acceptors for Biometric Monitoring

Polina Jacoutot, Alberto D. Scaccabarozzi, Tianyi Zhang, Zhuoran Qiao, Filip Aniés, Marios Neophytou, Helen Bristow, Rhea Kumar, Maximilian Moser, Alkmini D. Nega, Andriana Schiza, Antonia Dimitrakopoulou-Strauss, Vasilis G. Gregoriou, Thomas D. Anthopoulos, Martin Heeney, Iain McCulloch, Artem A. Bakulin, Christos L. Chochos, Nicola Gasparini

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Recent efforts in the field of organic photodetectors (OPD) have been focused on extending broadband detection into the near-infrared (NIR) region. Here, two blends of an ultralow bandgap push–pull polymer TQ-T combined with state-of-the-art non-fullerene acceptors, IEICO-4F and Y6, are compared to obtain OPDs for sensing in the NIR beyond 1100 nm, which is the cut off for benchmark Si photodiodes. It is observed that the TQ-T:IEICO-4F device has a superior IR responsivity (0.03 AW-1 at 1200 nm and −2 V bias) and can detect infrared light up to 1800 nm, while the TQ-T:Y6 blend shows a lower responsivity of 0.01 AW-1. Device physics analyses are tied with spectroscopic and morphological studies to link the superior performance of TQ-T:IEICO-4F OPD to its faster charge separation as well as more favorable donor–acceptor domains mixing. In the polymer blend with Y6, the formation of large agglomerates that exceed the exciton diffusion length, which leads to high charge recombination, is observed. An application of these devices as biometric sensors for real-time heart rate monitoring via photoplethysmography, utilizing infrared light, is demonstrated.

Original languageEnglish (US)
Article number2200580
JournalSmall
Volume18
Issue number15
DOIs
StatePublished - Apr 14 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • General Chemistry
  • Biomaterials
  • General Materials Science

Keywords

  • biometric sensors
  • NIR sensors
  • non-fullerene photodetectors
  • organic photodetectors
  • very low bandgap polymers

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