Photoisomerization and Electrochemical Switching of Arylazopyrazoles in Self-Assembled Monolayers

Photoresponsive surfaces are attracting increasing interest, particularly because their physicochemical properties can be selectively and temporally controlled by a noninvasive stimulus. However, photoresponsive moieties are also known to respond to other stimuli, some of which are well-studied (e.g., temperature and pH), while others are less understood. This work presents the first demonstration of a combined photochemical and electrocatalytic response of azo-based molecular photoswitches embedded in self-assembled monolayers, revealing a previously unrecognized functional synergy that yields electrochromic behavior potentially suitable for optoelectronic applications. The molecular design facilitates catalytic electrochemical switching, allowing for the transition of the photoswitches between three different states and enabling electrocatalytic control over Z to E azo bond isomerization. Ultimately, the coupling of photo- and electrochemical responses in self-assembled monolayers may eventually enable molecular synapses for application in neuromorphic nanoelectronics and molecular electronics.