In recent decades, the demand for clean energy has spurred extensive research into solar cells as a crucial renewable energy source. Among the various emerging absorber layer materials, Kesterite-type semiconductors have garnered significant interest. Particularly, the Kesterite Cu ₂ZnSnS ₄(CZTS) stands out due to its direct bandgap, high optical absorption coefficient, suitable bandgap (1.39~1.52 eV), and abundance of constituent elements, making it a promising candidate for low-cost thin-film solar cells. However, the power conversion efficiency (PCE) of CZTS-based solar cells currently lags behind that of Cu(In,Ga)Se ₂(CIGS) cells, primarily due to a large open-circuit voltage deficit caused by abundant cation disorder and defect clusters, leading to non-radiative recombination and band-tail states.
To address these challenges, partial or complete cation substitution has emerged as a viable strategy to modify the deleterious defects in CZTS. This study proposes a heterovalent substitution of Zn in CZTS, exploring the potential of novel quaternary chalcogenides A ₂M ₂M'Q ₄(A = Na, K, Rb, Cs, In, Tl; M = Cu, Ag, Au; M' = Ti, Zr, Hf, Ge, Sn; Q = S, Se, Te) as absorbers for solar cells. By substituting elements in five prototype structures, a comprehensive material database comprising 1350 A ₂M ₂M'Q ₄compounds was established.
High-throughput screening and first-principles calculations were employed to evaluate the thermodynamic stability, band gaps, spectroscopic limited maximum efficiency (SLME), and phonon dispersion of these compounds. Our findings reveal that 543 compounds exhibit thermodynamic stability ( E _hull< 0.01 eV/atom), 202 compounds possess suitable band gaps (1.0 ~ 1.5 eV), and 10 compounds meet all the criteria for thermodynamic and dynamic stability, suitable band gaps, and high optical absorption performance (10 ⁴~ 10 ⁶cm ^-1), with theoretical SLME values exceeding 30%.
Notably, Ibam-Rb ₂Ag ₂GeTe ₄exhibited the highest SLME (31.8%) among these candidates, featuring a band gap of 1.27 eV and a small carrier effective mass (< m ₀). The electronic structures and optical properties of these compounds are comparable to those of CZTS, making them promise for application in highly efficient single-junction thin-film solar cells.
All the data presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00006.(https://www.scidb.cn/s/naU7J3)