Spin-crossover nanoparticles anchored on MoS2 layers for heterostructures with tunable strain driven by thermal or light-induced spin switching.

TLDR: In this paper, spin crossover nanoparticles were covalently grafted onto functionalized layers of semiconducting MoS2 to form a hybrid heterostructure and the spin crossover caused a substantial and reversible change of the electrical and optical properties of the heterostructures.

Abstract: In the past few years, the effect of strain on the optical and electronic properties of MoS2 layers has attracted particular attention as it can improve the performance of optoelectronic and spintronic devices. Although several approaches have been explored, strain is typically externally applied on the two-dimensional material. In this work, we describe the preparation of a reversible ‘self-strainable’ system in which the strain is generated at the molecular level by one component of a MoS2-based composite material. Spin-crossover nanoparticles were covalently grafted onto functionalized layers of semiconducting MoS2 to form a hybrid heterostructure. Their ability to switch between two spin states on applying an external stimulus (light irradiation or temperature change) serves to generate strain over the MoS2 layer. A volume change accompanies this spin crossover, and the created strain induces a substantial and reversible change of the electrical and optical properties of the heterostructure. Spin-crossover nanoparticles have been covalently grafted onto a semiconducting MoS2 layer to form a self-strainable heterostructure. Under light or thermal stimulus, the nanoparticles switch between their high- and low-spin states, in which they have different volumes. This generates a reversible strain over the MoS2 layer and, in turn, alters the electrical and optical properties of the heterostructure.