Design and study of SrSnX2 (X=N, P, Sb, As, Bi) semiconductors using density functional theory

A series of novel, low-cost materials SrSnX2 (X=N, P, Sb, As, Bi) is explored through density functional theory in terms of structural, electronic, and optical properties to underline the usage of these compounds as photo-absorber materials. Within the modified Becke-Johnson exchangecorrelation potential, SrSnN2 shows a direct band gap of 1.94 eV while other materials in the series show a natural intermediate band which supports the two-step optical transition and hence increases the absorption in the visible energy region. Calculated values of the effective mass of electrons, effective densities of conduction, and valence states are found comparable with typical photovoltaic materials (Si and CdTe). We have obtained a high open-circuit voltage of 1.75 V, fillfactor of 0.92 with maximum efficiency of about 23% under one sun condition with a thickness of 10 nm which suggests that SrSnBi2 stands as a potential candidate for photovoltaics. The calculated band-edges concerning normalizing hydrogen electrode appeal their use as efficient photo-electrocatalyst for water splitting. Overall, we suggest that the natural intermediate band gap-materials are promising candidate for low-cost and efficient photovoltaic and photoelectrocatalytic applications.

Automated summary

A series of novel, low-cost materials SrSnX2 (X=N, P, Sb, As, Bi) were investigated for their structural, electronic, and optical properties using density functional theory. The results suggest that SrSnN2 has a direct band gap of 1.94 eV, while other materials in the series exhibit a natural intermediate band, increasing absorption in the visible energy region. The effective mass of electrons, effective densities of conduction and valence states of these materials are comparable to typical photovoltaic materials. SrSnBi2 shows promising potential as a candidate for photovoltaics, with a high open-circuit voltage, fill factor, and efficiency under one sun condition. The calculated band-edges indicate their potential as efficient photo-electrocatalysts for water splitting. Overall, the natural intermediate band gap-materials show promise for low-cost and efficient photovoltaic and photoelectrocatalytic applications.