Designing a Concentrated High-Efficiency Thermionic Solar Cell Enabled by Graphene Collector

TL;DR

This paper introduces a high-efficiency thermionic solar cell design using graphene as a collector, achieving over 10% efficiency under 600 suns and up to 12.8% under 800 suns, surpassing many existing solar technologies.

Contribution

It presents an analytical model for a concentrated thermionic solar cell with graphene, demonstrating the potential for significantly higher efficiency than current designs.

Findings

Achieves over 10% efficiency under 600 sun concentration.

Maximum efficiency of 12.8% under 800 sun concentration.

Diamond-graphene configuration yields highest efficiency.

Abstract

We propose a concentrated thermionic emission solar cell design, which demonstrates a high solar-to-electricity energy conversion efficiency larger than 10\% under 600 sun, by harnessing the exceptional electrical, thermal and radiative properties of the graphene as a collector electrode. By constructing an analytical model that explicitly takes into account the non-Richardson behavior of the thermionic emission current from graphene, space charge effect in vacuum gap, and the various irreversible energy losses within the subcomponents, we perform a detailed characterization on the conversion efficiency limit and electrical power output characteristics of the proposed system. We systematically model and compare the energy conversion efficiency of various configurations of graphene-graphene and graphene-diamond and diamond-diamond thermionic emitter, and show that utilizing diamond films as an emitter and graphene as a collector offers the highest maximum efficiency, thus revealing the important role of graphene in achieving high-performance thermionic emission solar cell. A maximum efficiency of 12.8\% under 800 sun has been revealed, which is significantly higher than several existing solid-state solar cell designs, such as the solar-driven thermoelectric and thermophotovoltaic converters. Our work thus opens up new avenues to advance the efficiency limit of thermionic solar energy conversion and the development of next-generation novel-nanomaterial-based solar energy harvesting technology.