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[Display omitted] • This paper introduces four two-dimensional inorganic biphenylene-like structures based on ZnS and CdS. • Phonon dispersion and ab initio molecular dynamics (AIMD) simulations were used to demonstrate the dynamical and thermal stabilities. • All evaluated structures are ultra-wideband gap semiconductors, with band gap energy values from 3.59 to 5.34 eV. • p-BPN-ZnS demonstrated the highest Young modulus (Y x /Y y = 25.295/34.874 N/m), followed by p-BPN-CdS (Y x /Y y = 15.286/21.339 N/m). • Notably, b-BPN-ZnS displayed a particular characteristic, a negative Poisson ratio (ν x /ν y = -0.008/-0.030), being an auxetic material. This study presents four novel inorganic structures based on the biphenylene network (BPN): planar BPN-ZnS (p-BPN-ZnS) and BPN-CdS (p-BPN-CdS) and buckled BPN-ZnS (b-BPN-ZnS) and BPN-CdS (b-BPN-CdS). Cohesive energy analyses reveal that structural buckling enhances stability, and a perturbation is necessary to obtain planar lattices. Phonon dispersion and ab initio molecular dynamics (AIMD) simulations demonstrated the dynamical and thermal stabilities. ZnS-based structures exhibited more pronounced charge accumulation and depletion than CdS. All evaluated structures are ultra-wideband gap semiconductors, with band gap energy values of 4.33, 5.34, 3.59, and 4.30 eV (at HSE06 level) for p-BPN-ZnS, b-BPN-ZnS, p-BPN-CdS, and b-BPN-CdS, respectively. p-BPN-ZnS demonstrated the highest Young modulus (Y x /Y y = 25.295/34.874 N/m), followed by p-BPN-CdS (Y x /Y y = 15.286/21.339 N/m). On the other hand, b-BPN-ZnS and b-BPN-CdS exhibit lower Young Modulus, Y x /Y y = 4.135/14.709 and 11.842/8.218 N/m, respectively. Notably, b-BPN-ZnS displayed a particular characteristic, a negative Poisson ratio (ν x /ν y = -0.008/-0.030), being an auxetic material. This report is expected to stimulate both theoretical and experimental researchers in the prediction and development of new inorganic materials based on the biphenylene network. [ABSTRACT FROM AUTHOR]

In recent years, several atomically thin two-dimensional (2D) materials have been reported with remarkable properties that prospect them as potential structures for nanotechnological applications. Advancing the research of layered structures, in this work, a new 2D inorganic material based on germanium carbide (GeC) and characterized by 4-, 6- and 12-membered rings, named inorganic graphenylene-like germanium carbide (IGP-GeC), is proposed via density functional theory (DFT) simulations to predict its structural, electronic, and mechanical properties. This structure has a direct band gap energy (2.65 eV), which can be modulated from 3.39 eV to a conductor character by applying a biaxial strain (ε) from −12% to 12%, making it a promising contender for nanoelectronics applications. IGP-GeC has an in-plane dielectric constant of 7.15 that increases with tensile strain, reaching 10.51 (ε = 12%), an exciting result in comparison with other 2D materials, also leading to remarkable excitonic properties in both unstrained and strained conditions. Besides this, the effective masses analysis denotes great stability of the charge carriers for IGP-GeC, improved by the tensile strain application. Finally, molecular dynamics (MD) simulations show that IGP-GeC is stable at 1200 K, and the absence of imaginary modes in the phonon bands attests to the dynamical stability of this novel 2D material, which will be useful to experimentalists in further studies. [Display omitted] • Inorganic graphenylene-like germanium carbide (IGP-GeC) is a new 2D material with mechanical, thermal and dynamical stability. • IGP-GeC has a central ring diameter of 7.18 Å, being possible the improvement of ions and molecules interacting with the nanosheet. • Having a bang gap energy of 2.65 eV, IGP-GeC characterizes as a semiconductor in the visible range of light. • Under biaxial strain engineering, the gap energy of IGP-GeC varies from 3.39 eV to metallic behavior. • The electron-hole recombination observed for IGP-GeC makes it a 2D material with promising excitonic properties. [ABSTRACT FROM AUTHOR]