Organic-inorganic hybrid perovskites have become one of the most promising photovoltaic technologies of the last decade, paving the way for the development of even more efficient solar panels at an affordable cost. A perovskite cell can be combined with a silicon cell to form a tandem cell with optimized light absorption. Today, this technology has achieved a record efficiency of 34.9%.
The CEA Tandem Solar Cells Laboratory (LCT) at the INES Institute is developing silicon/perovskite tandem solar cells. One of the main stumbling blocks to the spread of this technology is its stability over time. Indeed, the ionic nature of the perovskite absorber and various problems at the interfaces lead to degradation mechanisms that may or may not be reversible. These problems are closely linked to illumination, temperature and their variations (day/night and thermal cycles).
The LCT implements accelerated tests (continuous or cyclic illumination, thermal cycling, electrical bias) to understand degradation mechanisms according to cell architecture, and to predict behavior in real-life rooftop situations. This last aspect is crucial to guarantee the reliability of future commercial tandem panels, with lifetimes equivalent to those of today's silicon panels.
The candidate will produce his/her own devices according to the laboratory's state of the art. These cells may be encapsulated using the laboratory's reference process. Accelerated stability tests will be carried out with different climatic chambers at the LCT, including one capable of alternating day/night cycles at different temperatures. This latter chamber will be used to apply accelerated aging modes which, in recent studies, have demonstrated their ability to reproduce real outdoor behavior. In addition, the candidate will be able to modify the cell to integrate so-called “passivating” layers to improve stability, adapt the current of each sub-cell of the tandem structure, or analyze spectral effects on cell performance. Finally, the candidate will benefit from the LCT's expertise in terms of characterization (electrical measurements, photoluminescence, electron microscopy, XRD, etc.) as well as from the contribution of Grenoble's nanocharacterization platform with advanced characterization tools (XPS, cAFM, TOF-SIMS, etc.).