Band gap tailoring in a low toxicity and low-cost solar cell absorber Cu3SbS4 through Na alloying: A first-principles study

High power conversion efficiency, high stability, low cost, and environmentally friendly manufacturing are the main requirements for a commercializable photovoltaic device. Cu3SbS4 is an eco-friendly and earth-abundant compound that is studied as a potential solar cell absorber. However, its band gap is smaller than the ideal value. In this work, the possibility to modulate and improve the band gap by sodium alloying has been investigated by means of the first-principles density functional theory with the HSE06 hybrid functional. Our results demonstrate that the Cu3-xNaxSbS4 alloy with a high alloying concentration should be possible to realize, and that the Na incorporation widens the gap. An alloy concentration of x approximate to 0.64 yields the desired gap for a solar light absorber, which can then lead to a more efficient solar cell.

Automated summary

Research shows that it is possible to modulate the band gap of Cu3SbS4 by sodium alloying, and the incorporation of sodium widens the gap. An alloy concentration of x approximately 0.64 yields the desired gap for absorbing solar light, leading to improved efficiency of solar cells.