[108] Enhanced Device Absorption Efficiency and Photocatalytic Response of Monolayer PtX₂ (X = S, Se, Te) for Photocatalysis and Solar Cell Applications

Using density functional theory, the electronic and optical properties of monolayer platinum dichalcogenides (PtX₂) are calculated. It is observed that PtS₂, PtSe₂, and PtTe₂ have indirect bandgap of 2.70, 1.94, and 0.82 eV, respectively, indicating their potential in light harvesting. According to the calculated absorption spectra, PtX₂ (X = S, Se, Te) absorbs the light extremely well in the visible range (300–700 nm), implying potential as third-generation solar absorber in tandem configuration. The calculated device absorption efficiency increases above 90% at smaller wavelengths (300–350 nm). As a result, strong absorption across the entire light spectrum, from visible to UV, is exhibited. Interestingly, the top cell in tandem architecture requires a wider bandgap and strong device absorption efficiency, and these conditions are perfectly fulfilled by the materials PtS₂ and PtSe₂. The narrower gap (0.82 eV) and strong absorption of PtTe₂ make it an excellent candidate for bottom cell in tandem architecture. Furthermore, it is observed that PtX₂ family is useful for oxidizing H₂O into O₂ but fails to reduce H⁺ to H₂. Thus, suitable bandgap, photocatalytic property for splitting water, and strong absorption efficiency make PtX₂ an efficient candidate for application in optoelectronic devices, photocatalysis, and solar cells.