Investigation of thermal conductivity of monolayer MoS2 supported on PDMS substrates with varying adhesion under different tensile strains

Abstract

Atomically thin molybdenum disulfide (MoS2) has emerged as a promising candidate for next-generation flexible electronic devices due to its exceptional physical properties. However, in practical applications, a degree of interfacial sliding occurs between the flexible substrate and the two-dimensional (2D) material, which significantly impacts thermal transport properties of the materials. In this work, we prepared three types of polydimethylsiloxane (PDMS) substrates with varying adhesion by adjusting the mixing ratios of pre-polymer and curing agent (10:1, 15:1, and 20:1) and subsequently investigated the thermal conductivity of monolayer MoS2 supported on different PDMS substrates under uniaxial tensile strains from 0% to 6% via the optothermal Raman technique. Our results demonstrate a decreasing trend in the thermal conductivity of MoS2 with increasing tensile strain. In addition, we found that at a 6% substrate strain, the thermal conductivity of MoS2 on high-adhesion (20:1) and low-adhesion (10:1) PDMS substrates decreased to 28.2 ± 5.5 W/(m K) and 43.4 ± 6.1 W/(m K), respectively, marking reductions of 52% and 33% from their respective 0% strain values [58.5 ± 14 W/(m K) and 64.5 ± 12.8 W/(m K)]. This work reveals the influence mechanism of flexible substrates with different adhesion on the measurement of 2D material thermal properties, providing a scientific basis for the thermal management design of flexible electronic devices in high-strain environments.