Maphanga, Rapela RSantosh, MSRugute, EDima, Ratshilumela SMondal, PMaleka, Prettier MTshwane, David MMaluta, ERtimif, S2025-02-282025-02-2820240927-02561879-0801https://doi.org/10.1016/j.commatsci.2024.113576http://hdl.handle.net/10204/14104This work employs density functional theory (DFT) to investigate the structural, electronic, and optical properties of XAlS2 (X =Li, Na, K, Rb, and Cs) nanomaterials for potential use in photovoltaic applications. A comprehensive first-principles analysis has been conducted using GGA-PBE, GGA-PBEsol, and LDA functionals to examine LiAlS2, NaAlS2, KAlS2, RbAlS2, and CsAlS2. The findings reveal distinctive band gaps within this set of materials, with LiAlS2 and NaAlS2 exhibiting indirect band gaps and KAlS2, RbAlS2, and CsAlS2 possessing direct band gaps. Analyzing the partial density of states indicates that the valence band predominantly arises from S-3p and Al-3p orbitals, showcasing covalent bonding through hybridization. Furthermore, the examination of the optical properties of XAlS2 materials suggests their notable light absorption in the ultraviolet range, positioning them as promising candidates for photovoltaic applications. Additionally, the lattice thermal conductivity of two dynamically stable systems has been investigated and their thermoelectric properties have been calculated. Notably, a dimensionless figure of merit of 2.78 for LiAlS2 has been identified, marking it as a strong contender for high-temperature thermoelectric applications.AbstractenDensity functional theoryDFTNanomaterialsXAlS2 materialsArticleN/A