Patrice Miska1

1, University of Lorraine, Nancy, , France

The search of new materials and semiconductors for optoelectronic applications is a challenging task and a growing activity exists in that field. Among the various criteria to be fulfilled for new materials, environmental aspects are very important as well as the use of non-toxic and highly recyclable elements.
For terawatt-scale energy needs the electrical energy supply will certainly go toward an energy mix. Photovoltaics could then be the backbone of such a renewable energy system. To fulfil the challenging price targets and to develop new markets the design and production of solar cells working at highest efficiencies is essential all by fulfil the green and sustainable aspects. Different ways exist for the PV devices improvement such as tandem cells. Nevertheless, those technologies require the use of scarce materials such as indium and gallium. Moreover, III-V tandem cells mainly require up to now the use of epitaxial growth that remain both expensive and limiting for large scale realization. Other technologies are also studied such as new quaternary thin films but making cells can require the use of toxic elements (such as cadmium) so their use and acceptance for large scale applications is therefore limited.
In the field of lighting devices, LEDs are will replace the classic sources of light because of their good efficiency. Here again, the material used contain indium and the current technology must be improved to overcome the "green gap" restriction.
I will describe few results of study of new materials that could be used for both PV and lighting technologies. It could be for example nitride materials of the Zn-IV-N2 family or oxides and nanomaterial used as new absorber for solar cells or as emitting materials.
For example, ZnSnN2 contain abundant and non-toxic elements. Very recently, it has been shown that ZnSnN2 is a promising n-type material for photovoltaic applications [1]. Since this nitride has been scarcely studied, it is necessary to continue research activities to optimize its functional properties, more especially on silicon. Moreover, adding germanium could also be of great interest for LED applications. Other results about (nano)materials such as oxide will also be described.
1] A. N. Fioretti at al., Advanced Electron. Mater. 1600544 (2017)