An Organic Electrochemical Transistor Integrated Photodetector for High Quality Photoplethysmogram Signal Acquisition

Yizhou Zhong, Anil Koklu, Diego Rosas Villalva, Yongcao Zhang, Luis Huerta Hernandez, Maximilian Moser, Rawad K. Hallani, Iain McCulloch, Derya Baran, Sahika Inal*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The organic photodiode (OPD) is a promising building block for solution-processable, flexible, lightweight, and miniaturized photodetectors, ideal for wearable applications. Despite the advances in materials used in OPDs, their photocurrent and light responsivity are limited, and alternative methods are required to boost the signal response. Herein, a miniaturized organic electrochemical transistor (OECT) is integrated with an OPD module to unlock the potential of OPDs to acquire physiological signals. In this integrated photodetector (IPD) system, the light intensity regulates the OPD voltage output that modulates the OECT channel current. The high transconductance of the OECT provides efficient voltage-to-current conversion, enhancing the signal-to-noise ratio on the sensing site. A microscale, p-type enhancement-mode OECT with high gm and fast switching speed performs better in this application than depletion-mode OECT of the same geometry. The IPD achieves a photocurrent and responsivity 318 and 140 times higher than the standalone OPD, respectively. It is shown that with the IPD, the amplitude of the photoplethysmogram signals detected by the OPD is enhanced by a factor of 2.9 × 103, highlighting its potential as a wearable biosensor and to detect weak, often uncaptured, light-based signals from living systems.

Original languageEnglish (US)
Article number2211479
JournalAdvanced Functional Materials
Volume33
Issue number6
DOIs
StatePublished - Feb 2 2023

Keywords

  • integrated sensors
  • organic electrochemical transistors
  • organic photodiodes
  • photoplethysmograms

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Biomaterials
  • General Materials Science
  • Condensed Matter Physics
  • Electrochemistry

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