Six‐arm Stellat Dendritic‐PbS Flexible Infrared Photodetector for Intelligent Healthcare Monitoring

Abstract

The flexible photodetector plays an important role in improving human medical health status. However, the narrow spectral detection range, poor stress stability, and non‐degradation of traditional flexible photodetectors greatly hinder the further development of wearable medical devices. In this paper, a novel flexible infrared photodetector is proposed for intelligent healthcare monitoring using high purity lead sulfide (PbS) nanoparticles on paper‐based flexible substrate synthesized by hydrothermal method and physical friction. The excellent performance of the detector is attributed to the 1.01 eV band gap and six‐arm stellate dendritic structure of PdS, a good combination between PbS and paper substrate via physical friction. As a result, our photodetector demonstrates wide‐spectrum detection capabilities from 365 to 1550 nm. The photodetector at 980 nm (50.4 μW cm−2) shows responsivity of 6.45 mA W−1, detectivity of 6.4 × 1010 Jones, response recovery time of 0.36 s/0.41 s, with good mechanical stability. By comparison, our detector has a wider detection range, better weak signal detection performance, and shorter response time than the performance of the former paper‐based detector. Furthermore, the paper‐based PbS photodetector as a dual‐wavelength photoplethysmography sensor is applied to analyze the oxygen saturation and develop an intelligent bandage to monitor wound healing. This paper‐based PbS photodetector has tremendous potential in the field of wearable medical devices and intelligent medical applications are expected.

Advances in Biosignal Sensing and Signal Processing Methods with Wearable Devices

“…with permission from ACS. (E) Flexible infrared photodetector for PPG application, reprinted from, [37] copyright(2022), Zhang et al. with permission from Wiley.…”

“…Figure 4D illustrates a textile‐like carbon nanotube‐based PPG device for blood oxygen sensing at the finger, permitting use of this ideal PPG sensing location while maintaining the unobtrusiveness and flexibility characteristic of wearables [36] . Figure 4E demonstrates flexible infrared photodetector for PPG application [37] while Figure 4F presents a foot pressure sensor utilizing optical characteristics and capillary force [38] . Figure 4G describes a device sleep apnea detection with integrated PPG sensor placed at the sternum, requiring fine‐tuning of the applied pressure to maximize signal quality in this challenging sensing location [39] .…”

“…(D) Fiber optoelectronic microelectrodes in smart textile applications., reprinted from, [36] copyright(2020), Kim et al with permission from ACS. (E) Flexible infrared photodetector for PPG application, reprinted from, [37] copyright(2022), Zhang et al with permission from Wiley. (F) Optical and capillary filled foot pressure sensor, reprinted from, [38] copyright(2021), Ballaji et al with permission MDPI.…”

Self-Powered and Broadband Bismuth Oxyselenide/p-Silicon Heterojunction Photodetectors with Low Dark Current and Fast Response

“…Photodetectors are an indispensable basic component to convert the received optical signals into electrical signals in optoelectronic systems and have been widely used in industry and military, such as optical communication, biomedical diagnostics, environmental monitoring, missile warning, and astronomical exploration . The inorganic two-dimensional (2D) electronic materials, such as graphene, black phosphorus, − and transition metal dichalcogenides, , have attracted a lot of attention due to their thickness-dependent electronic band structures, flat architectures, high mechanical flexibility, and electronic tunability.…”

Simple and Productive Method to Develop Highly Sensitive and Fast Infrared Photodetector Using Spray Deposited Nanocrystalline PbS Thin Film

“…Lead sulfide (PbS) with a cubic structure and a small bandgap (0.4 eV) has reported high photosensitivity in the infrared (IR) range [1][2][3][4]. Along with this PbS nanostructures are also used as temperature sensors, solar cells, photomultipliers, photoresistors, and selective sensors based on lead ions [5][6][7].…”