AIMD simulations were performed at work temperature (350 K) by using the Nosé-Hoover method to verify the thermostability of selected 2D monolayer hybrid halide perovskites. A supercell consisting of 3 × 3 × 1 unit cells for selected 2D monolayer hybrid halide perovskites was constructed to perform AIMD simulations. A 5 ps NVT ensemble molecular dynamics simulation trajectory with a 0.5 fs time step was collected for selected 2D monolayer hybrid halide perovskites. Furthermore, the adsorption energy calculations were performed for the environmental stability of selected 2D monolayer hybrid halide perovskites. A supercell was constructed by stacking 3 × 3 × 1 unit cells with a vacuum space larger than 20 Å along the c-axis. The absorptions of water/oxygen on the surface of 2D hybrid halide perovskites were investigated. The H 2 O binding energy E ads here was defined as To investigate the quantum transport properties of selected 2D monolayer hybrid halide perovskites, we constructed a vertical transport architecture device with Au electrodes acting as the source and drain contacts and 2D monolayer hybrid halide perovskites serving as the transport channel region. Our simulations were performed by using the first-principles methods, combined with the combination of the Keldysh non-equilibrium Green's function formalism and density functional theory (NEGF-DFT), implemented in the first principles quantum transport software package Nanodcal. The local density approximation (LDA) was adopted to describe the exchange and correlation function, and atomic cores were defined by the standard norm-conserving nonlocal pseudo potentials. A double-ζ polarized (DZP) atomic orbital basis was used for the metal electrode (Au atom) and 2D monolayer hybrid halide perovskites to expand all physical quantities with a kinetic energy cutoff of 3000 eV.