EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Low-temperature thermophotovoltaics (TPV) demands very low band gap (< 0.5 eV) semiconductors to maximize output power. As the band gap narrows down, so does the number of available materials. Current technology is mostly based on epitaxially-grown alloys of III-V elements, such as InGaAs(Sb), which present some limitations. First, it is not always possible to obtain the desired band gap, due to technological constraints. Second, their fabrication methods are expensive, an issue that becomes more and more important as lower temperature systems are aimed, because the output TPV power density diminishes rapidly with temperature. Colloidal quantum dots (CQD) are an interesting alternative to epitaxial materials for low-temperature TPV. The band gap of these nanocrystals can be tunned precisely during their synthesis by changing their size. Thus, in principle, any desired optimum bad gap for low-temperature TPV could be achieved by choosing the right combination of material and nanocrystal size. In addition, CQDs are fabricated by low-cost, wet chemical methods. These characteristics allow envisaging efficient, low-cost TPV cells. We give an overview of the potential of CQDs as photovoltaic absorbers for low-temperature TPV devices and review the state-of-the-art.