Conceptual Developments of Aryldiazonium Salts as Modifiers for Gold Colloids and Surfaces

Modified colloids and flat surfaces occupy an important place in materials science research due to their widespread applications. Interest in development of modifiers that adhere strongly to surfaces relates to need for stability under ambient conditions in many applications. Diazonium salts have evolved as primary choice for modification of surfaces. The term diazonics has been introduced in literature to describe the science and technology of aryldiazonium salt-derived materials. The facile reduction of diazonium salts via chemical or electrochemical processes, irradiation stimuli, or spontaneously results in efficient modification of gold surfaces. Robust gold-aryl nanoparticles, where gold is connected to aryl ring through bonding to carbon and films modified by using diazonium salts, are critical in electronics, sensors, medical implants, and materials for power sources. Experimental and theoretical studies suggest that gold-carbon interactions constructed via chemical reactions with diazonium salts are stronger than nondiazonium surface modifiers. This invited feature article summarizes conceptual development of recent studies of diazonium salts in our laboratories and others with a focus on surface modification of gold nanostructures, flat surfaces and gratings, and their applications in nanomedicine engineering, sensors, energy, forensic science, and catalysis.