Earth abundant nitride for tandem solar cell – NITA

Tandem solar cells are considered as the most promising technology for obtaining high efficiencies. , Up to know, efficiencies >30% have only been obtained with costly III-V multi-junctions and III-V/Si tandem solar cells. Other materials are also intensively investigated by the photovoltaic community (perovskite, CuInGa(S,Se)2, organic), but they contain toxic or scarce elements and have limited performances.
NITA project proposes an original alternative to reach the market expected efficiencies by developing a top cell based on (Zn1 – xMgx)3N2 alloy compatible with the c-Si technology, and which do not contain toxic or scarce elements.
The heart of the NITA project is to combine Zn3N2 and Mg3N2 to elaborate the new ternary (Zn1 – xMgx)3N2 alloy for which the bandgap energy can be tuned from 1.0 eV to 2.9 eV. Reaching 1.7 eV is very desirable since it represents the ideal bandgap energy for the top cell of the tandem solar cell architecture based on monocrystalline silicon (c-Si) technology. In the (Zn1-xMgx)3N2 alloy, the ideal value of 1.7 eV is reached for a composition of x~0.4.
The development of new technologies for reasonable-cost, high-efficiency tandem solar cells, based on non-critical material represents a unique opportunity to re-start a competing PV industry in Europe. NITA main objective will have a strong societal impact by developing a low-cost green energy source allowing to become independent of the current fossil energies. Indeed, replacing the fossil energy by photovoltaic solar panel will also benefit the ecological transition that Europe has planned to achieve by 2030.