[en] Full text : Design of chalcogenide photovoltaic absorbers is carried out systematically through sequential cation mutation, from binary to ternary to quaternary compounds, using first-principles electronic structure calculations. Several universal trends are found for the ternary and two classes of quaternary chalcogenides. For example, the lowest-energy structure always has larger lattice constant a, smaller tetragonal distortion parameter η=c/2a, and larger band gap than the metastable structures for common-row cation mutations. The band gap is reduced during the mutation. The band gap decreases from binary II-VI to ternary I-III-VI₂ are mostly due to the p-d repulsion in the valence band, the decreases from ternary I-III-VI₂ to quaternary I₂-II-IV-VI₄ chalcogenides are due to the downshift in the conduction band caused by the wavefunction localization on the group IV cation site. It was found that I₂-II-IV-VI₄ compounds are more stable in the kesterite structure, whereas the widely-assumed stannite structure reported in the literature is most likely due to partial disorder in the I-II layer of the kesterite phase. Among the derived quaternary compounds, Cu₂ZnSnS₄ (CZTS) is one of the ideal candidate absorber materials for thin-film solar cells with an optimal band gap, high absorption coefficient, abundant elemental components, and is adaptable to various growth techniques. It was performed a series of first-principles electronic structure calculations for CZTS. Also it was found that in the ground state kesterite structure, (i) the chemical potential region that CZTS can form is very small. Therefore, it will be very difficult to obtain high quality stoichiometric CZTS samples; (ii) The dominant p-type acceptor in CZTS is CuZn, however, the associated acceptor level is relatively high, suggesting that p-type doping in CZTS is more difficult than ternary compounds such as CuInSe₂; (iii) The formation of the self-compensated defect pair [CuZn+ZnCu] will not lead to a strong carrier separation, and thus will not contribute the same beneficial effect observed in ternary chalcopyrite compounds; (iv) We predict that to avoid the aforementioned issues in (ii) and (iii), it will be optimal to grow the sample under Cu-poor/Zn-rich conditions, so VCu and ZnCu become the dominant defects in the system. However, in this case, non-equilibrium growth techniques may be required to avoid the formation of secondary phases. All predictions will be compared with available experiments