Reversible valence tautomerism induced by a single-shot laser pulse in a cobalt-iron prussian blue analog

A photoinduced reversible valence tautomerism (RVT) induced by a 2.38 eV excitation line above 200 K was demonstrated. The bidirectional phase transitions, together with a color change between reddish brown and purple, can nearly be completed within a nanosecond, but only if the absorbed photon density was higher than a threshold value. The presented photo-transition compounds with thermal hysteresis, especially for those with a hysteresis loop around room temperature, which will open up quite appealing perspectives concerning the design of molecular-based memory devices and displays.