Electrical sensing of the thermal and light induced spin transition in robust contactless spin-crossover/graphene hybrid devices

TL;DR

This paper presents a robust, scalable hybrid device combining spin-crossover molecules with graphene, capable of fast, contactless electrical detection of light-induced spin transitions with high efficiency.

Contribution

It introduces a novel, industry-compatible fabrication method for SCO/graphene devices that enables rapid, contactless detection of spin transitions with high yield.

Findings

Fast light-induced spin transition detection (~50% yield in 5 min)

Enhanced performance with PMMA layer (~100% yield in 5 min)

Robust device fabrication compatible with electronics industry protocols

Abstract

Hybrid devices based on spin-crossover (SCO)/2D heterostructures grant a highly sensitive platform to detect the spin transition in the molecular SCO component and tune the properties of the 2D material. However, the fragility of the SCO materials upon thermal treatment, light irradiation or contact with surfaces and the methodologies used for their processing have limited their applicability. Here, we report an easily processable and robust SCO/2D hybrid device with outstanding performance based on the sublimable SCO [Fe(Pyrz)2] molecule deposited over CVD-graphene, which is fully compatible with electronics industry protocols. Thus, a novel methodology based on growing an elusive polymorph of [Fe(Pyrz)2] (tetragonal phase) over graphene is developed that allows us to electrically detect a fast and effective light-induced spin transition in the devices (~50% yield in 5 minutes). Such performance can be enhanced even more when a flexible polymeric layer of PMMA is inserted in between the two active components in a contactless configuration, reaching a ~100 % yield in 5 minutes.