Infrared Organic Photodetectors Employing Ultralow Bandgap Polymer and Non‐Fullerene Acceptors for Biometric Monitoring. Issue 15 (4th March 2022)

• Record Type: Journal Article
• Authors: Jacoutot, Polina; Scaccabarozzi, Alberto D.; Zhang, Tianyi; Qiao, Zhuoran; Aniés, Filip; Neophytou, Marios; Bristow, Helen; Kumar, Rhea; Moser, Maximilian; Nega, Alkmini D.; Schiza, Andriana; Dimitrakopoulou‐Strauss, Antonia; Gregoriou, Vasilis G.; Anthopoulos, Thomas D.; Heeney, Martin; McCulloch, Iain; Bakulin, Artem A.; Chochos, Christos L.; Gasparini, Nicola
• Is Part Of: Small. Volume 18:Issue 15(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-04
• Subjects: biometric sensors -- NIR sensors -- non‐fullerene photodetectors -- organic photodetectors -- very low bandgap polymers; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202200580
• Languages: English
• ISSNs: 1613-6810

Abstract

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. Abstract : Here, organic photodetectors (OPD) comprising an ultralow bandgap polymer and non‐fullerene acceptors delivering light‐to‐current conversion from 350 to 1800 nm with a specific detectivity of 10 9 –10 10 Jones are shown. A practical application of the NIR OPD as biometric heart rate sensors using photoplethysmography technique is demonstrated.