Dr. Nisar, Muhammad

In the field of material science, the search for a material with an optimal bandgap of approximately 1.40 eV that can act as an efficient photocatalyst for water splitting using solar spectrum irradiation is a noble mission. In this article, we explore the structural, electronic structure, optical and photocatalytic properties of Zr2CO2/MoS2 vdW heterostructures. Our results demonstrates that the Zr2CO2/MoS2 vdW heterostructure can be reliably synthesized. This is due to a minimal lattice mismatch of less than 3%, a negative adhesion energy of -4.23 meV/Å 2, and inherent dynamic stability. The electronic band structure calculations indicate that the Zr2CO2/MoS2 vdW heterostructure is an indirect bandgap semiconductor. We found that the conduction band minimum (CBM) and valance band maximum (VBM) of the heterostructure are located in different monolayers. Furthermore, under −2 % biaxial strain a transition from type-I to type-II (staggered) band alignment occurred. Stacking 2D MoS2 on the Zr2CO2 monolayer results in a vdW heterostructure, and as a result, the HSE calculated bandgap of the Zr2CO2/MoS2 vdW heterostructure in most stable configuration lying in the ideal range for photocatalytic applications. We also studied the heterostructure’s optical properties to understand its response to incident photons with energies up to 14 eV. Based on our findings, Zr2CO2/MoS2 heterostructures are desirable for optoelectronic device applications operated in visible range. Our research offers fresh recommendations for developing novel, highly effective photocatalytic compounds with numerous optical device applications.

In this study, we conducted first-principles calculations interfaced with Boltzmann transport theory to examine the carrier-dependent thermoelectric properties of CrS2−xTex (x: 0, 1, 2) dichalcogenides monolayers. We conducted a systematic analysis of the structural, phonon band structures, elastic properties, electronic structures, and thermoelectric properties, of electron (e) and hole (h) doped CrS2−xTex (x: 0, 1, 2) dichalcogenides monolayers. The studied 2D TMDCs exhibit structural stability, as indicated by the negative formation energy. Additionally, the phonon band structures indicate no negative frequencies along any wave vector, confirming the dynamic stability of the CrS2−xTex monolayers. CrS2 and CrTe2 monolayers are semiconductors with direct bandgaps of 1.01 and 0.67 eV, respectively. A Janus CrSTe monolayer has a smaller bandgap of 0.21 eV. Temperatures range between 300 and 500 K, and concentrations of e(h) doped in the range of 1.0 × 1018−1.0 × 1020 cm−3 are used to compute the thermoelectric transport coefficients. The low lattice thermal conductivity is predicted for the studied compounds, among which Janus CrSTe and CrTe2 have the minimum value of κlat ≈ 1 W/mK @ 700 K. The figure-of-merit ZT projected value at the optimal e(h) doping concentration for the CrS2 monolayer is as high as 0.07 (0.09) at 500 K. Our findings demonstrate how to design improved thermoelectric materials suitable for various thermoelectric devices.