Although thiophosphates with 2D structural dimensionality have received particular attention, data mining from the MP database reveals that most of the known PSs actually have 3D dimensionality (Fig. ). For quaternary and quinary PSs, the share of 3D-structured materials is even higher than what is found in ternary systems (Fig. ). Interestingly, most of the 2D-structured materials appear in the P/S = 1/3 category (Fig. ) in combination with the [P 2 S 6 ] 4-polyanion (Fig. ). The predominance of 3D structures is encouraging for optoelectronic energy conversion application, because 3D structural dimensionality is usually a necessary (though not sufficient ) condition for good photocarrier transport in all directions. Specifically, 3D structures with high spatial-and energy overlap between the orbitals constituting their band edges usually result in high band dispersion and low effective masses of electrons and holes in all directions. Since μ is inversely related to the effective mass, low effective masses are usually correlated with high carrier mobilities. Indeed, all the inorganic PV absorbers with demonstrated efficiencies above 15% have 3D structural dimensionality.