The field of photovoltaic conversion of solar energy has seen spectacular growth in recent years. From being practically negligible less than 10 years ago, and growing at a rate of almost 40% a year, photovoltaic module production is beginning to appear in the energy supply. It could account for between 4% and 12% of electricity production in Europe by 2020, and continue to grow over the following decades, making it one of the main sources of renewable energy. To achieve this, an unprecedented mobilization of players in the field, from researchers to manufacturers, not forgetting public authorities and the general public, has begun and must continue to grow. Researchers include physicists and specialists in electronic devices, but we often forget a category of researchers who also play a key role in the development of photovoltaics: chemists. Indeed, the field is by nature highly interdisciplinary, and progress is linked to the synergies created between these different specialties. Neglecting any one of them means missing out on a source of progress in knowledge and device performance. The aim of this presentation is therefore to show the role played by chemists and chemistry in past and future developments in photovoltaics.
After a general presentation of the photovoltaic field, showing the different current pathways, starting with the silicon pathway, then the thin-film pathways (Si, CdTe, CIS), we examine how chemistry has made decisive contributions, whether in silicon purification, thin-film synthesis, or understanding materials and interfaces. We also consider its contribution to the design of new, less costly production processes, such as chemical methods adapted to the treatment of large surfaces, without the need for high vacuum as in conventional semiconductor technologies, using atmospheric pressure deposition by electrolysis, silk-screen printing, sol-gel, where obtaining quality materials involves complex physico-chemical processes that must be mastered. We then analyze the growing role of chemistry in the emergence of new photovoltaic concepts, starting with advances in the field of nanostructured dye cells, which combine a nanoporous oxide matrix (TiO2, ZnO) with dye molecules grafted onto its surface and communicating on the other side with an electrolytic impregnation phase. This is an emerging field at the interface between photovoltaics and biology (photosynthesis). This evolution continues with research into all-organic cells. Over the next few years, chemistry could thus evolve from its traditional (if little-known) position in the development of materials and processes, to that of a major source of innovation and inspiration for new photovoltaic concepts.
