• Energy Research
• French National Research Agency (AN... close
• OA Publications Mandate: No close
• 2016 close

Inorganic thin film photovoltaics (PV) are mainly based on CdTe, amorphous Si or CIGS. In the most recent times, hybrid organo-metal halide perovskites have emerged with the highest conversion efficiencies reported of 20.1 %. However, these materials present stability, reliability, scalability and toxicity problems. Of course, research in this area is focusing hard on these challenges, but success is not guaranteed. Alternative inorganic oxides could offer significant advantages. The ideal bandgap of an active photovoltaic layer for the solar spectrum is around 1.3 eV. However oxides with low bandgaps are scarce. One of the most studied oxides as an active photovoltaic layer to date is cuprous oxide, Cu2O. Its bandgap is around 2.1 eV and so it is not ideal for the solar spectrum. Its conversion efficiencies do not generally exceed 4%. In this project we propose to study an emerging type of solar cells that is based on ferroelectricity. In this type of solar cell, a p-n junction is not necessarily needed, as opposed to conventional cells. Interesting efficiencies start to be obtained with this type of solar cells (up to 8.1 %, in 2015), yet the mechanisms are still not well understood and there are several materials and engineering issues to be tackled. The objective of this project is to initiate a game-changing photovoltaic technology based on new multifunctional inorganic oxide materials with suitably low bandgaps. These oxides are stable, non-toxic, abundant and processable by a range of scalable methods. Radically enhanced performance is certainly possible through incorporating multifunctionality into them. There are five highly structured WPs in this project which when put together will ensure the greatest chance of success. We aim to synthetize ferroelectric materials that absorb a large part of the solar spectrum and have reduced bandgaps. We will explore four types of materials with promising properties: BiMnO3, doped BiFeO3, Bi2FeCrO6, and doped TbMnO3. For these materials, the project will consist in growing thin films and assess their structural, optical and electrical properties to better understand these materials. Then, the most promising materials will be integrated into all oxide solar cells and their potential for photovoltaics will be evaluated.