LAUSR

We theoretically investigate Sn(II) phosphates as optoelectronic materials using first-principles calculations. We focus on known prototype materials SnnP2O5+n (n = 2, 3, 4, 5) and a previously unreported compound, SnP2O6 (n = 1), which we find using global optimization structure prediction. The electronic structure calculations indicate that these compounds all have large band gaps above 3.2 eV, meaning they are transparent with visible light. Several of these compounds show relatively low hole effective masses (∼2–3 m0), comparable the electron masses. This suggests potential bipolar conductivity depending on doping. The dispersive valence band-edges, underlying the low hole masses, originate from the antibonding hybridization between the Sn 5s orbitals and the phosphate groups. Analysis of structure–property relationships for the metastable structures generated during the structure search shows considerable variation in combinations of band gap and carrier effective masses, implying chemical tunability...