From the temperature dependent phononic studies of few layered liquid phase exfoliated MoS₂ nanosheets we find that the E¹_2g (in-plane) and A_1g (out-of-plane) Raman modes follow red shift with increase in temperature and exhibits non-linear temperature dependence in the entire temperature range (80 to 600 K). The first-order temperature coefficients for E¹_2g and A_1g modes are found to be -0.0133 cm^-1K^-1 and -0.0092 cm^-1K^-1, respectively. The physical origin of the non-linear temperature dependence is analyzed using an analytical model that includes contribution of the thermal expansion and an-harmonic effects to the lattice potential. Our analysis suggests that the non-linear temperature dependence of E¹_2g and A_1g modes mainly originates from the an-harmonic contributions from three-phonon and four-phonon scattering.

Keywords: Layered Materials; Liquid Phase Exfoliation; Phonon Scattering;