Direct Electricity Generation Mediated by Molecular Interactions with Low Dimensional Carbon Materials—A Mechanistic Perspective

Next-generation off-the-grid electronic systems call for alternative modes of energy harvesting. The past two decades have witnessed the evolution of a wide spectrum of low dimensional carbon materials with extraordinary physical and chemical properties, ideal for microscale electrical energy storage and generation. Tremendous progress has been made in harnessing the energy associated with the interactions between these nanostructured carbon substrates and the surrounding molecular phases, subsequently converting them into useful electricity. This review summarizes the important theoretical and experimental milestones the field has reached to date, and further classifies these energy harvesting processes based on underlying physics, into five mechanistically distinct classes—phonon coupling, Coulombic scattering, electrokinetic streaming, asymmetric doping, and capacitive discharging. With a special mechanistic focus, the authors hope to resolve the fundamental attributes shared by this diverse array of molecular scale energy harvesting schemes, offer perspectives on key challenges, and ultimately establish design principles that guide further device optimization.