PhD student: High-performance photovoltaics through the assembly of thick nanoparticle-based mi[...]

Laboratory of Physics and Chemistry of Nano-Objects (LPCNO-UMR 5215 INSA-CNRS-UPS) @ Toulouse

PhD in the field of nanotechnology

Duration: 3 years

Location: Toulouse (France), on the INSA campus

Keywords: Nanoparticles, quantum dots, directed assembly, microfabrication, photovoltaics

Scientific context

Faced with the climate emergency, improving the performance of photovoltaic technologies is a major challenge for the energy transition. Currently, silicon-based solar panels plateau at efficiencies of around 20%, largely due to a fundamental mismatch between the incident solar spectrum and the silicon's absorption capacity.

A promising way to bypass this limitation is to integrate light conversion layers capable of transforming solar photons into wavelengths better suited to silicon. These layers rely on photoluminescent nanoparticles (quantum dots ), which are able to absorb and re-emit light in a controlled manner.

However, current approaches remain limited by:

• the need for thick layers (1–2 μm) for efficient absorption,
• challenges in structuring at the micro/nano scale,
• strong constraints related to the use of non-polar solvents, which are not compatible with conventional deposition techniques.

In this context, our team has recently developed and patented a innovative directed self-assembly method based on Convective Self-Assembly (CSA) coupled with functionalized microstructured substrates. This approach allows the formation of organized 3D architectures of nanoparticles, paving the way for a new generation of optical conversion layers.

Objectives of the thesis

The objective of this thesis is to design and fabricate 3D microstructured light conversion films , integrating different populations of quantum dots to effectively cover the entire solar spectrum (Fig.1c).

To achieve this goal, the project will revolve around three major axes:

• Instrumental development : setting up of an advanced experimental device for CSA deposition in non-polar solvents;
• Architecture design : optimizing microstructure geometries to maximize light absorption and conversion;
• Multi-material assembly : developing strategies for the controlled organization of several types of nanoparticles within the same structure.

This thesis will be mainly experimental and will take place in a cleanroom environment. It will combine:

Fabrication : deposition of quantum dots by convective self-assembly on microstructured substrates (photolithography);

• Advanced characterization : fluorescence microscopy, optical interferometry, atomic force microscopy (AFM), scanning electron microscopy (SEM);
• Performance evaluation : analysis of the optical and conversion properties of the resulting structures.

All the necessary equipment is available in the laboratory.

Candidate profile

• Degree: Master’s (M2) or Engineering school degree
• Qualities: scientific curiosity and initiative, autonomy and experimental rigor, and a taste for working in an advanced technological environment
• English: good level required (written and oral)

Why choose this project?

• A project with a high societal impact , at the heart of current energy challenges
• An approach at the frontier between physics, nanoscience and engineering
• The opportunity to work on an emerging patented technology
• A rich and multidisciplinary experimental environment

Funding

The thesis is funded by the "Doctoral Allocations on Societal Issues" of INSA Toulouse.

Contacts

Giuseppe BONIELLO (Associate Professor at INSA Toulouse)

Laurence RESSIER (Professor at INSA Toulouse)

Bibliographical references

(1) Boniello and Ressier, FR , 2025