Description du sujet de thèse

The goal of this PhD is to explore and develop new concepts and new fabrication process for single-junction and multi-junction solar cells. The work will be first devoted to ultrathin single-junction solar cells. The team has achieved state-of-the-art results for single-junction GaAs solar cells. The first objective is to extend these results to silicon solar cells, and to explore and compare two emerging concepts: (1) multi-resonant absorption that can be achieved using perfectly ordered structures (arrays) fabricated by nanoimprint lithography, and (2) directional scattering obtained using structures with correlated disorder, fabricated by self-assembled nanopatterning techniques such as polymer-blend and colloidal lithography. The low-cost fabrication processes will be developed and optimized, and their performances will be analyzed by optical spectroscopy. Then, they will be compared to optical simulation results and applied to ultrathin silicon solar cells. The goal is to demonstrate state-of-the-art performances using original designs and affordable fabrication processes.

The second objective is to investigate and improve light-management in tandem solar cells. Owing to their high number of layers and additional constraints, such as the balance of absorption in the top and bottom cells, emerging tandem solar cells raise new challenges for photon management (transparency of the top cell and intermediate layers, selective light-trapping in the top and bottom cells...). First, reliable optical models will be developed in order to simulate accurately current tandem devices fabricated in our team and in the IOTA French project. Second, nanopatterning will be implemented in tandem solar cells in order to improve light management, and new architectures of devices will be proposed and tested. This work will take advantage of the original bonding process currently developed in the team, which offers new degrees of freedom to insert nanostructures in intermediate layers, between the top and the bottom cells.

Contexte de travail

This doctoral project is part of the IOTA targeted project (Innovative Tandem Cell Architectures) of PEPR TASE. The PhD student will benefit from C2N facilities (nanotechnologies, clean room, characterization means), and will work in close collaboration with LAAS (Toulouse).

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Risks inherent in working in cleanrooms.