The analysis in the previous section indicates that it might be necessary to move beyond the already-known ternary PSs to find more than a handful of candidates for high-quality semiconductors. Assuming that PSs with band gaps in the visible are plentiful (Fig. ), the key questions are where to Only materials with an electronic band structure calculation available on MP are considered. Thus, the materials shown here for each metal cation and P/S ratio do not always correspond to the ones shown in Fig. . In the case of two materials with equal stoichiometry and Ehull, preference is given to the one with the smaller sum over the effective masses of both carriers. The effective masses are extrapolated from the MP band structures using the BoltzTraP2 package at room temperature and under low doping density. The position in the periodic table indicates the third constituent element of each PS.