An investigation of the 2D Rb2O monolayer intrinsic properties from a theoretical perspective using DFT

In this research, Density Functional Theory (DFT) was employed to investigate the 1T phase of the Rb2O monolayer. The structural, electronic, optical, and thermal properties were studied utilizing the WIEN2k software. The band gaps found using GGA, LDA, mBJ, and hybrid correlation were 0.52 eV, 0.49 eV, 1.52 eV, and 1.17 eV. The phonon dispersion curve is implemented to assess the Rb2O monolayer's dynamical stability. The thermal stability is assessed using the Car-Parrinello Molecular Dynamics (CPMD) code of Quantum espresso. The absorption coefficient attains its peak value of 35.74 cm−1 at 9.72 eV. Based on the optical property results, the Rb2O monolayer shows promise in designing photovoltaic devices. At 400K, the Figure of merit found to be 0.85 which indicates that the Rb2O monolayer can be used for waste heat recovery systems. The excitonic effects are ascertained by the effective masses of the holes and electrons. •Rb2O monolayer possess a trigonal honey-comb structure.•Dynamic stability of a compound can be inferred from the phonon distribution curve.•Rb2O monolayer has an ionic nature.•The Rb2O monolayer is found to be a viable candidate for designing waste heat recovery systems.•The value of the relative ratio is found to be 2.86.