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Updated: Dec 20, 2025

Asymmetric Thermoelectrochemical Cell for Harvesting Low-grade Heat under Isothermal Operation
Published on: February 5, 2020
Integrated near-field thermo-photovoltaics for heat recycling
Gaurang R Bhatt1, Bo Zhao2, Samantha Roberts3
1Department of Electrical Engineering, Columbia University, New York, NY, 10027, USA. grb2116@columbia.edu.
Abstract:
Energy transferred via thermal radiation between two surfaces separated by nanometer distances can be much larger than the blackbody limit. However, realizing a scalable platform that utilizes this near-field energy exchange mechanism to generate electricity remains a challenge. Here, we present a fully integrated, reconfigurable and scalable platform operating in the near-field regime that performs controlled heat extraction and energy recycling. Our platform relies on an integrated nano-electromechanical system that enables precise positioning of a thermal emitter within nanometer distances from a room-temperature germanium photodetector to form a thermo-photovoltaic cell. We demonstrate over an order of magnitude enhancement of power generation (Pgen ~ 1.25 μWcm-2) in our thermo-photovoltaic cell by actively tuning the gap between a hot-emitter (TE ~ 880 K) and the cold photodetector (TD ~ 300 K) from ~ 500 nm down to ~ 100 nm. Our nano-electromechanical system consumes negligible tuning power (Pgen/PNEMS ~ 104) and relies on scalable silicon-based process technologies.
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