An Electrical Conductance Study of the Spin State Switching Behavior of [Co(SQ)(Cat)(3-tpp)₂] Spin Crossover Molecular Thin Films

Spin crossover molecules are a class of organic materials possessing spin states that can be switched on a molecular level. Their unique properties make them intriguing candidates for future molecular based electronic devices. This is important due to the limits imposed by Moore’s law for current electronics which necessitates the development of new technology. The spin states of spin crossover molecules can be switched by a number of external stimuli, including thermal switching at a transition temperature, light induced spin state switching (usually at low temperature) and switching induced by electric or magnetic fields. While the typical method of inducing spin state switching in [Co(SQ)(Cat)(3-tpp)₂] molecules is by thermal switching at its transition temperature of about 100°C. Our experiments show this type of molecule tends to lock in a given spin state. To facilitate spin state switching, we used temperature combined with an applied voltage and irradiation by light of specific wavelengths.