(M/F): PhD Thesis: Radiative Cavity Design and Integration for Thermophotovoltaic Systems

Organisation/Company CNRS Department Laboratoire Procédés, Matériaux et Energie Solaire Research Field Mathematics History » History of science Researcher Profile First Stage Researcher (R1) Application Deadline 13 Apr 2026 - 23:59 (UTC) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 35 Offer Starting Date 1 Oct 2026 Is the job funded through the EU Research Framework Programme? Not funded by a EU programme Is the Job related to staff position within a Research Infrastructure? No

Offer Description

The PhD will be carried out within the PROMES laboratory (CNRS), a leading research center in concentrated solar energy and high-temperature systems. The research will take place at the Odeillo site, which hosts unique facilities for solar energy research, including high-flux solar furnaces and an experimental platform for solar thermophotovoltaics. The project is part of the ANR DIVERSITY project, which involves collaboration with several French research laboratories working on thermophotovoltaic cells, photonic structures, and energy-conversion systems. This collaborative environment will provide the candidate with exposure to optical modeling, photovoltaics, high-temperature experimentation, and solar energy technologies.

Thermophotovoltaic (TPV) systems convert thermal radiation emitted by a hot surface into electricity using lowbandgap photovoltaic cells. By directly converting high-temperature heat into electricity, TPV systems offer a promising pathway for compact and high-efficiency energy conversion.In recent years, rapid progress has been achieved in TPV cell performance, with record efficiencies exceeding 40% under laboratory conditions. However, translating these advances into complete energy-conversion systems remains a major challenge. In particular, the efficiency of a TPV system depends not only on the cells themselves but also on how thermal radiation is transferred from the emitter to the cells.A key component in this regard is the radiative cavity surrounding the emitter. This cavity controls how thermal radiation is exchanged between the emitter and the photovoltaic cells, influencing the spatial distribution of radiative flux, photon recycling, and optical losses. Its geometry and optical properties therefore play a central role in determining the overall efficiency of the subsystem.Designing such cavities is a complex problem that combines radiative heat transfer, optical engineering, and high-temperature system design. While simplified models often assume idealized geometries or perfect emitters and reflectors, real systems must account for losses, non-uniform flux distributions, material limitations, and experimental constraints. Developing realistic cavity architectures and validating them experimentally is therefore an essential step toward practical TPV energy conversion.Scientific Motivation:This PhD addresses a central challenge in thermophotovoltaic engineering: how to design radiative cavities that efficiently couple high-temperature emitters to TPV cells in realistic experimental systems.From a scientific perspective, radiative cavities provide a rich platform for studying radiative heat transfer in confined geometries. The exchange of thermal radiation within such cavities depends on geometry, surface properties, and temperature distributions, and often requires advanced modeling tools to be accurately described.From a technological perspective, optimizing radiative cavities is critical to improving the performance of TPV subsystems. Efficient cavity designs must maximize useful photon flux reaching the cells while minimizing optical and thermal losses.Despite their importance, relatively few experimental studies have explored realistic TPV cavity architectures, particularly under conditions relevant to solar-driven thermophotovoltaic systems. By combining numerical modeling with experimental development, this PhD aims to bridge the gap between theoretical cavity designs and practical TPV subsystem implementation.Objectives of the PhD Project:The goal of this PhD is to simulate, build, and experimentally validate a thermophotovoltaic radiative cavity.The work will be structured around three main research questions:

Research Questions

1. How does cavity geometry influence radiative transfer in TPV systems?The first part of the thesis will focus on modeling radiative exchange between a thermal emitter, the surrounding cavity, and TPV cells. The candidate will develop simulation tools (ray tracing and radiative transfer modeling) to study how cavity geometry, reflectivity, and emitter characteristics affect radiative flux distribution and subsystem efficiency. Particular attention will be given to flux uniformity on the photovoltaic cells and to optical losses within the cavity. These simulations will guide the design of realistic cavity geometries suitable for experimental implementation.
2. How can a TPV cavity subsystem be experimentally realized?The second part of the thesis will focus on the design and construction of a laboratory TPV cavity subsystem. The candidate will participate in the mechanical and optical design of the cavity, select suitable materials and reflective surfaces, and assemble the experimental setup. The system will integrate a high-temperature emitter, reflective cavity walls, and TPV cells provided by ANR project partners. Instrumentation of the setup will include temperature measurements, electrical characterization of the TPV cells, and diagnostics for analyzing subsystem performance.
3. How can this subsystem be integrated into a solar thermophotovoltaic setup?In the final part of the thesis, the cavity subsystem will be integrated into an experimental solar thermophotovoltaic platform at PROMES. The candidate will explore the operation of the system under realistic high-temperature conditions using concentrated solar radiation. Experiments will investigate subsystem efficiency, stability, and operating regimes under solar illumination. The results will be compared with simulation predictions to refine the design and improve understanding of radiative transfer in practical TPV systems.