# Near-Field Enhanced Thermionic Energy Conversion for Renewable Energy Recycling

## TL;DR

This paper introduces a novel near-field enhanced thermionic energy conversion system that significantly improves power generation efficiency by utilizing near-field thermal radiation to excite electrons at lower temperatures, promising advances in renewable energy recycling.

## Contribution

The paper presents a new hybrid system combining near-field thermal radiation with thermionic conversion, achieving higher efficiency and power output at lower operating temperatures.

## Key findings

- Energy conversion efficiency exceeds 40%.
- Thermionic power output increases by over 10 times.
- System operates effectively at lower temperatures.

## Abstract

This article proposes a new energy harvesting concept that greatly enhances thermionic power generation with high e ciency by exploiting the near- field enhancement of thermal radiation. The proposed near-field enhanced thermionic energy conversion (NETEC) system is uniquely configured with a low-bandgap semiconductor cathode separated from a thermal emitter with a subwavelength gap distance, such that a significant amount of electrons can be photoexcited by near-field thermal radiation to contribute to the enhancement of thermionic current density. We theoretically demonstrate that the NETEC system can generate electric power at a significantly lower temperature than the standard thermionic generator, and the energy conver- sion e ciency can exceed 40%. The obtained results reveal that near-field photoexcitation can enhance the thermionic power output by more than 10 times, making this hybrid system attractive for renewable energy recycling.