Rational Assembly of Superstructure Microparticles into Mosaic‐Like Highly Oriented Monolayer for Glucose‐Responsive Electrodes

Abstract Assembly of functional superstructure microparticles into large‐scale transferable ensembles is a practical approach to elaborate collective properties for catalytic and sensing applications. Here, a two‐step assembly process is proposed to fabricate a mosaic‐like highly oriented monolayer consisting of densely packed CuI superstructure microparticles (s‐CuI) over a large area. First, optimized synthesis and Cl doping of rectangular sheet‐like s‐CuI is achieved by antisolvent crystallization. Then, a steep capillary gradient is created along the water surface to compress the pre‐dispersed s‐CuI into a centimeter‐sized mosaic‐like highly oriented monolayer, which can be integrally transferred onto fluorine‐doped tin oxide glass substrates. The s‐CuI monolayer with optimal Cl doping exhibits a highly sensitive electrochemical response to glucose in a nonenzymatic weakly alkaline environment. A photoelectrochemical response to glucose can also be achieved in nonenzymatic neutral solution. The high performances are ascribed to large surface area, excellent electrical contact, and consistently exposed Cu⁺ active sites of the s‐CuI building blocks.