Thermoelectric properties of XX- and XY-stacked GeS/GeSe van der Waals heterostructures from DFT and BTP calculations.

This study utilizes density functional theory (DFT) and the Boltzmann transport equation (BTE) to investigate the structural, electronic, and thermoelectric properties of germanium sulfide (GeS) and germanium selenide (GeSe) monolayers, along with their van der Waals (vdW) heterostructures. We analyzed XX-stacked and XY-stacked configurations, where the XX configuration features direct atomic stacking, while the XY configuration exhibits staggered stacking. Our first-principles calculations indicate that the formation of GeS/GeSe heterostructures results in a reduction of bandgaps compared to their bulk and monolayer counterparts, yielding bandgap values of 0.

Novel Janus gamma-Pb XY monolayers with high thermoelectric performance X=S, Se and Y=Se, Te X Y.

The quest for efficient thermoelectric materials has intensified with the advent of novel Janus monolayers exhibiting exceptional thermoelectric parameters. In this work, we comprehensively investigate the structural, electronic, transport, phonon, and thermoelectric properties of novel Janus -Pb XY (X=S, Se; Y=Se, Te; X Y) monolayers using density functional theory combined with the Boltzmann transport equation. Our findings unveil the energetic, dynamic, thermal, and mechanical stability of these monolayers, along with their remarkable thermoelectric performance.

Structural and Electronic Properties of Bulk ZnX (X = O, S, Se, Te), ZnF, and ZnO/ZnF: A DFT Investigation within PBE, PBE + , and Hybrid HSE Functionals.

Here, we have studied the crystalline structure of bulk ZnX (X = O, S, Se, Te) and ZnF systems as a first step to understand the structures like ZnX and Zn-based systems like ZnO/ZnF interfaces, which are of utmost importance for possible technological applications. In addition, an adequate methodological description based on density functional theory (DFT) calculations is necessary. It is well known that plain DFT calculations based on local or semilocal exchange-correlation functionals fail to describe the correct band gap energy for these systems, whereas nonlocal approaches, such as hybrid-based functionals, can compensate the underestimation of band gap.

Band alignment and charge transfer predictions of ZnO/ZnX (X = S, Se or Te) interfaces applied to solar cells: a PBE+U theoretical study.

The engineering of semiconductor materials for the development of solar cells is of great importance today. Two topics are considered to be of critical importance for the efficiency of Grätzel-type solar cells, the efficiency of charge separation and the efficiency of charge carrier transfer. Thus, one research focus is the combination of semiconductor materials with the aim of reducing charge recombination, which occurs by spatial charge separation.