Self-powered implantable CMOS photovoltaic cell with 18.6% efficiency

Zhao, J., Parvizi, R., Ghannam, R. , Law, M.-K., Walton, F. , Imran, M. A. and Heidari, H. (2023) Self-powered implantable CMOS photovoltaic cell with 18.6% efficiency. IEEE Transactions on Electron Devices, 70(6), pp. 3149-3154. (doi: 10.1109/TED.2023.3268630)

Abstract

Harvesters for implantable medical applications need to generate enough energy to power their loads, but their efficiency is reduced when implanted under the tissue. Conventional photovoltaic (PV) cell harvesters made with CMOS technology stack cells in series, which raises output voltage but lowers power conversion efficiency. In addition, it is difficult to assess harvester performance prior to fabrication. To address these challenges, we developed a novel parallel PV cell configuration that fully utilizes all triple-well diodes and responds efficiently to near-infrared light. Using an optimized structure, the PV cells were fabricated through standard TSMC 65-nm CMOS technology, achieving an efficiency of 18.6%, open circuit voltage of 0.45 V, and short circuit current of 1.9 mA cm −2 . These results confirm the ability of the device to generate sufficient energy even when implanted beneath the tissue. Multiphysics finite element modeling (FEM) was used to optimize the stacking structure of the CMOS PV cell, and experimental results showed a successfully delivered power density of 1.2 mW cm −2 (single cell 1.04 mm 2 ) when placed 2 mm below porcine skin. Different array configurations of six PV cells were also experimentally studied using external wire switching, demonstrating the flexibility of the PV array in delivering different output energy for various implantable devices.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Walton, Mr Finlay and Parvizi, Dr Roghaieh and Imran, Professor Muhammad and Ghannam, Professor Rami and Zhao, Mr Jinwei and Heidari, Professor Hadi
• Authors: Zhao, J., Parvizi, R., Ghannam, R., Law, M.-K., Walton, F., Imran, M. A., and Heidari, H.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity; College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: IEEE Transactions on Electron Devices
• Publisher: IEEE
• ISSN: 0018-9383
• ISSN (Online): 1557-9646
• Published Online: 01 May 2023
• Copyright Holders: Copyright © 2023 IEEE
• First Published: First published in IEEE Transactions on Electron Devices 70(6): 3149-3154
• Publisher Policy: Reproduced with the permission of the Publisher

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
300137		Impact Acceleration Account - University of Glasgow 2017	Jonathan Cooper	Engineering and Physical Sciences Research Council (EPSRC)	EP/R511705/1	Research and Innovation Services
303466		HERMES	Hadi Heidari	European Commission (EC)	824164	ENG - Electronics & Nanoscale Engineering