Optical properties of WTe2-a layered topological insulator: A DFT study

•The 2H WTe2 shows semiconducting nature with in band gap and phonon dispersion curve reveals it’s dynamically stability.•The topological insulator nature has been confirmed by presence of spin orbit interaction mechanism.•The optical properties of 2H WTe2 for monolayer to quad layer have been studied for the first time.•The 2H WTe2 possesses high real part of dielectric function and refractive index in visible region and absorption coefficient in UV region, which show the promising applications in light harvesting.