Electroluminochromism: Classical Materials and New Developments
Electroluminochromism refers to reversible luminescence switching in response to external electrochemical or electric stimulus. The conventional mechanism of electroluminochromism includes the intrinsically electro-active and luminescent materials, which show modulated emission intensity at different redox states, and those composed of luminescent components and redox-active units, where the emission of the luminophore is modulated by activating or suppressing the electron or energy transfer process between individual components. Four types of classical electroluminochromic materials are discussed, including small organic molecules, emissive polymeric films, photofunctional transition-metal complexes, and emissive nanocomposite films. A particular focus is placed on the introduction of some new developments in this field, including near-infrared electroluminochromic materials, electroluminochromism driven by non-conventional mechanisms, and electroluminochromism with aggregation-induced emission or aggregation-enhanced emission-active materials. The device fabrications and applications of some particular materials will be briefly mentioned when they are discussed.