Controlled synthesis of Ag-alloyed Cu ₂ ZnSnS ₄ (ACZTS) thin films with wide range of Ag/Cu ratios via a solution process enables phase transition, lattice expansion, and bandgap tuning, yielding stable absorbers for next-generation photovoltaics.

The synthesis of polycrystalline TiFe₂Sn samples by a route including arc melting and spark plasma sintering with Hf, Y, and In substitutions at the Ti and Sn sites is investigated. For a reduced amount of substitution, around 2 at%, the samples are single phase, while for increased amounts, secondary phases segregate. As is characteristic of these compounds, the Fe-Ti atomic disorder generates a weak ferromagnetic ordering, which is also influenced by the type of substitutional atoms and the secondary phases in the samples with a higher Hf content. The Seebeck coefficient values show an increase for Ti_0.98Hf_0.02Fe₂Sn and for samples with an adjusted Sn content, resulting in slightly increased power factor values. These values reach a maximum for Ti_0.98Hf_0.02Fe₂Sn at approximately 300 K and for TiFe₂Sn_1.05 at approximately 325 K, namely, 2.69 × 10⁻⁴ Wm⁻¹K⁻² and 2.52 × 10⁻⁴ Wm⁻¹K⁻², respectively. The thermal conductivity of all the samples with substitutions increases with respect to the pristine sample. The highest figure of merit value of 0.016 is also obtained for Ti_0.98Hf_0.02Fe₂Sn at 325 K.