Review of Fe-based spin crossover metal complexes in multiscale device architectures

Metal complexes involving d4-d7 first-row transition metals exhibit spin-crossover (SCO) behaviour between low-spin and high-spin states in response to external stimuli such as temperature, pressure, voltage control and light irradiation. They are of interest in functional devices such as sensors, molecular electronics, spintronic devices, and well as memory and information processing applications. In particular, many electronic devices exploiting the SCO phenomena contain Fe-based SCO materials, which have shown significant performance. This paper reviews the state of the art and configurations of such functional devices on a range of scales. Utilisation of SCO functionality ranging from single molecule junctions to nanoparticles and thin films incorporated into horizontal and vertical junction device architectures, will be elaborated. This review provides a systematic overview in the characteristics of Fe-based SCO functional device and their corresponding performance. This understanding provides a pathway for further optimization of Fe-based SCO technologies in a wide range of electronic applications.