Emerging technologies and new concepts (multijunction, perovskite, organic, photoelectrochemical)

Contrary to what might have been expected, the development of photovoltaics is reflected in an exceptional dynamism in fundamental research into new materials, new concepts and new architectures that are likely to revolutionize established technologies in the coming years. The objectives are both to increase performance and to improve environmental and ecological impact.
In this lecture, we will present the range of these new approaches, with a particular focus on two chemically-derived pathways that are revolutionizing the conventional approach to inorganic materials. On the one hand, the organic photovoltaic sector (the counterpart of OLEDs for displays), which draws on the huge variety of organic molecules and polymers, including the emblematic fullerenes, and whose commercial development has already begun. On the other hand, the perovskite sector, based on an organic-inorganic hybrid material based on lead methylammonium iodide, which in just a few years has reached new heights in terms of performance, raising immense hopes within the research community.
The challenges ahead are many, ranging from understanding the fundamental properties of materials and interfaces, to optimizing manufacturing processes, controlling aging phenomena and increasing surface area. Nevertheless, industrial innovation is well underway, with the first manufacturing units currently under construction. The grail would in fact be of another order, that of coupling perovskite technology with crystalline silicon or CIGS technology for the manufacture of tandem cells enabling a fundamental breakthrough in theoretical efficiency from 29% to over 40%. Commercial modules with efficiencies of over 30% are expected by 2030. Finally, research based on photoelectrochemistry for the direct production of hydrogen or the reduction of_CO2 is also developing and raising great hopes.