In this paper, we investigate the stability and thermoelectric properties of 1 T PdSSe, PdSTe and PdSeTe Janus structures using density functional theory (DFT). All three systems are narrow gap semiconductors with indirect bandgaps of 0.94 eV, 0.33 eV and 0.34 eV respectively. Compared to transition metal dichalcogenide (TMD) monolayers, PdS ₂ and PdSe ₂ are semiconductors with wider indirect bandgaps of 1.29 eV and 0.69 eV respectively. Phonon dispersion calculations demonstrate that all pristine and Janus structures are mechanically stable despite the presence of negligible negative frequencies around the point in PdSTe and PdSeTe. Inspection of the lattice thermal conductivity ( ) shows that these structures are slightly anisotropic in the x and y directions except for PdSe ₂ which shows a higher degree of anisotropy. Influenced by the values of , the thermal electronic conductivity ( ), the electronic conductivity ( ) and the Seebeck effect ( S ), the figure of merit along the x (ZT ^xx )and y (ZT ^yy ) directions register the largest values in the case of electron doping for the PdSe ₂ and PdSeTe 2D crystals. Interestingly, the figures of merit of the Janus structures are larger than their corresponding pristine PdX ₂ (X = S, Se) structures. Once synthesized, such information is crucial for the implementation of the PdXY (Y = Se, Te) structures in industrial applications.

This study investigates the structural stability and electronic, mechanical, excitonic, and optical properties of 2D-XI₂ (X = Si, Ge, Sn, Pb) monolayers using both first-principles and semiempirical calculations. Our findings reveal that this group has semiconductor characteristics with band gaps from 2.35 to 3.28 eV at the HSE06 level. The excitonic effects are significant with exciton binding energies between 372 and 422 meV. They present a maximum solar harvesting efficiency, at the Shockley–Queisser limit, considering an electron–hole coupling of 16.37%. These findings indicate that these structures are promising for future optoelectronic applications, showing excellent visible and ultraviolet response and enhancing the photovoltaic cell performance.