Chalcogenoviologen-Based Surface and Interface Chemistry for Optoelectronic Applications: From Molecular Design to Functional Devices

ConspectusPhotoelectronic surface and interface chemistry plays a pivotal role in addressing global challenges in energy conversion, environmental sustainability, and intelligent manufacturing. Recent years have witnessed notable progress in this field, particularly in the development of chemical sensors, intelligent surfaces, and artificial photosynthetic systems, all grounded in the principles of photoelectronic surface and interface chemistry. The functionality of these systems depends critically on the photophysical properties of the molecular components, their spatial arrangement at interfaces, and the dynamics of interfacial electron transfer. However, the diversity of photoelectrochemical molecules, spatial constraints at surfaces and interfaces, and the complexities of interface coupling often introduce significant randomness and structural complexity, posing challenges for both fundamental research and practical applications. Over the past decade, we have developed a unique class of chalcogenoviologen-based systems that enable tuning photoelectronic behavior at surfaces and interfaces. By integrating molecular design with interfacial assembly, these systems provide a versatile platform for constructing functional optoelectronic architectures. This Account provides an overview of the design and synthesis of novel chalcogenoviologen derivatives, highlighting synthetic strategies that enhance spin-orbit coupling, reduce energy gaps and reduction potentials, and allow fine-tuning of photoelectric properties. Further, it discusses assembly methods for constructing chalcogenoviologen-based surfaces and interfaces through electrostatic, hydrogen bonding, and covalent strategies, with particular emphasis on multicomponent covalent and noncovalent architectures that enable controlled energy level alignment and directional electron transfer. This Account also presents our selected contributions to the application of these functional surfaces and interfaces across areas such as photocatalysis, electrochromic devices, energy storage, and intelligent visual sensing. The focus is particularly given to emerging applications in photo/sonodynamic therapy, electrochromic display, and aqueous organic redox flow batteries. Finally, this Account offers a perspective on the potential of molecular-level interface design in advancing next-generation optoelectronic technologies.