Electrochromic and photochromic behaviour in a single metal-organic framework containing a redox-active linker.

A Zr-based metal organic framework with naphthalene diimide teracarboxylate linkers is reported for its dual electrochromic and photochromic behavior. MOF crystals display reversible yellow to green photochromism upon exposure to visible light and colourless to dark-brown reversible electrochromism on applying a potential of 0 to -2.5 V. The MOF thin film shows good colouration efficiency at 550 nm, which is the highest sensitivity of the human eye.