Thermal transport in two-dimensional carbon nitrides: A comparative molecular dynamics study

Abstract

Two-dimensional (2D) carbon nitrides show a great structural diversity and have potentials in applications of thermal management and energy storage. Thus, seeking the thermal transport properties of 2D carbon nitrides is of great significance for improving the performance and reliability in practical applications. However, the experimental measurements for 2D materials are limited by various conditions, and the results of molecular dynamics (MD) simulations are quite different, e.g., the calculation results of thermal conductivity of C3N show a poor consistency. To this end, the characteristics of thermal transportation of 2D carbon-nitride nanostructures with the representatives of C3N, C2N, C3N4s(s-triazine), and C3N4t(t-triazine) are comprehensively investigated by molecular dynamics (MD) simulations using four different methods. The thermal conductivity of C3N is up to around 866Wm−1K−1 while that of C3N4t is down to around 19Wm−1K−1 in this work. Through spectral heat current (SHC) and phonon analysis, we find that the decrease of thermal conductivity for 2D carbon nitrides is due to the deterioration of out-of-plane thermal conductivity induced by regularly distributed holes and absence of CC bonds. The results show that the rate of heat tranfer in two-dimensional carbon-nitride nanostructures significantly relies on their nanostructures.