Laser‐Writable, Electrically Erasable Photoelectrochromic Organic Film

An organic photoelectrochromic film, in which methylene blue can change from blue to transparent on absorption of light, and return to blue by an oxidation reaction induced by an external electric field, is presented (see Figure). The resulting device presents the remarkable advantage of being driven by a red HeNe laser (5 mW) for the “writing process”, and by a very low voltage (0.4 V) for the “erasing process”.