Earth-abundant nontoxic ternary calcium nitrides inverse perovskites for single-junction solar cells: Ab-initio simulations

Abstract

A single-junction solar cell with a direct and ideal photovoltaic forbidden bandgap value which maximizes the photon absorbed is needed for the diversity of solar energy conversion, as well as other optoelectronic applications. Here, the ternary calcium nitrides inverse perovskites Ca3PN, Ca3AsN, Ca3SbN, and Ca3BiN were investigated in the frame of Density Functional Theory (DFT). The principal novelty of this research essentially projects detailed information on the structural, elastic, electronic, transport, and optical properties of Ca3PN, Ca3AsN, Ca3SbN, and Ca3BiN compounds. The understudy compounds are founded to be thermodynamically and elastically stable at ambient pressure. The electronic properties demonstrate that the understudy compounds have direct semiconductor behaviors with the ideal solar cells forbidden band gaps values which overlap very well with the visible zone of the solar spectrum leading to these materials high absorption coefficients percentage of around 80%, low reflectance and transmittance along the visible zone. Besides, the inter-atomic bonds between M and surrounded atoms are ionic while Ca–N inter-atomic bond is polar covalent. Otherwise, the understudy compounds exhibit low recombination rates as well as low charge carrier's effective masses which boost the carrier mobility. In addition, with rising temperatures up to 1000 K, the Ca3PN, Ca3AsN, and Ca3SbN compounds undergo from n to p-type semiconductor behaviors while Ca3BiN shows a p-type semiconductor behavior. While the CSN compound has better characteristics in TE applications at 50 K where the ZT value is 80%. Accordingly, these out studying properties make the understudy compounds as new single-junction solar cells non-silicon based.