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

Abstract

The organic photodiode (OPD) is a promising building block for solutionprocessable, 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 signalto-noise ratio on the sensing site. A microscale, p-type enhancement-mode OECT with high g m 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 × 10 3 , highlighting its potential as a wearable biosensor and to detect weak, often uncaptured, light-based signals from living systems.

Facile light exposure of zinc oxide via interfacial engineering for boosting responsivity and detectivity in organic photodetectors

“…Then, through a signal-tonoise ratio (SNR) analysis, real-time optical pulses of the lightexposed ZnO-based OPD device were confirmed at a frequency of 1 kHz, and the converted signal was obtained using FFT analysis (see Fig. 7(c) and (d)), 56,57 which was then compared with the white noise of OPDs beyond the 1/ƒ region. The photocurrent of the light-exposed ZnO-based OPD slightly increased in width, and it was evident that the noise was suppressed in the pulse (red line in Fig.…”

Enhanced sub-1 eV detection in organic photodetectors through tuning polymer energetics and microstructure

“…Notwithstanding, their lack of flexibility and costly manufacturing processes have left room for other emerging technologies such as organic photodetectors (OPDs) (3,4). Organic optoelectronics can address the fastgrowing demand for portable, lightweight, cost-effective sensors that are flexible and easy to integrate and scale (5)(6)(7)(8). Among notable benefits of organic semiconductors are broad and tunable absorption, solution processing, and a choice of deposition techniques onto soft, curved, or large surface areas.…”

Metallointercalated-DNA Nanotubes as Functional Light Antenna for Organic Photoelectrochemical Transistor Biosensor with Minimum Background

“…Photoelectrochemistry (PEC) has been a burgeoning technology in the field of advanced biosensing. − The intense interest in this arena arises from the advantages of semiconducting materials interfacing biological systems, the versatile interfacial interactions, and the reduced background due to the total separation and different energy types of the input (photons) and output (electrons) signals. Recent exploration of light-semiconductor-OECT interactions − has opened the light-controllable OECT with many new implementations and unknown possibilities. Among them, one of particular interest is the fusion between PEC and the OECT to realize an organic photoelectrochemical transistor (OPECT) with a minimum background, in which the rational light-matter interplay is of vital importance.…”