Structural, Electronic, and Optical Properties of 2D Penta‐PdSe ₂ and Penta‐PdPSe Heterostructures: A Computational Study

Using first‐principles calculations, we systematically investigated the structural, electronic, and optical properties of penta‐PdSe 2 and β‐phase penta‐PdPSe (monolayer to trilayer) and their heterostructures. Band structure analysis reveals a tunable bandgap in PdSe 2 that narrows with increasing layer thickness, while PdPSe remains metallic. Interestingly, the PdSe 2 /PdPSe heterostructure exhibits semiconducting behavior. Optically, PdSe 2 shows strong visible light absorption with a thickness‐dependent redshift, whereas PdPSe predominantly absorbs in the infrared, showing a corresponding blueshift. Stacking configurations are found to significantly modulate the heterostructure's absorption profile. Furthermore, doping bilayer PdSe 2 (with B, C, N, O at Pd/Se sites) induces diverse optical and electronic modifications. Transport simulations reveal a 10 9 ‐fold current enhancement in bilayer PdSe 2 and the heterostructure relative to the monolayer, alongside strong negative differential resistance in bilayer PdPSe. These findings underscore the high tunability of these systems, highlighting their potential for advanced optoelectronic applications.