2D MATERIALS FOR SUSTAINABLE ENERGY; PHOTOCATALYTIC AND PHOTOVOLTAIC PROPERTIES

Abstract

Two-dimensional (2D) materials have emerged as promising candidates for advancing sustainable energy technologies owing to their exceptional optical, electronic, and catalytic properties. Their atomically thin structures provide high surface area, tunable band gaps, and strong light–matter interactions, which are highly advantageous for solar-driven energy conversion. In this study, we investigate the photocatalytic and photovoltaic properties of representative 2D materials, including transition-metal dichalcogenides (TMDs), graphitic carbon nitride (g-C₃N₄), and MXenes, with emphasis on their structural–functional correlations. Photocatalytic analysis reveals that defect engineering, phase modulation, and heterostructure design significantly enhance charge separation and surface reaction kinetics, resulting in improved performance in hydrogen evolution and carbon dioxide reduction under visible-light irradiation. Photovoltaic evaluation demonstrates that 2D layers can function both as active light absorbers and as interfacial modifiers in perovskite and silicon solar cells, where they effectively suppress non-radiative recombination, improve carrier extraction, and enhance long-term stability. We report that device integration of 2D materials leads to measurable improvements in open-circuit voltage, fill factor, and overall power conversion efficiency. Moreover, the ability to engineer van der Waals heterostructures offers opportunities to construct ultrathin and flexible photovoltaic architectures. Collectively, our findings provide mechanistic insight into the role of atomic structure, defects, and interfacial engineering in dictating energy conversion efficiency. This work establishes a framework for rational design of 2D materials in both photocatalytic and photovoltaic systems, advancing their potential toward scalable applications in clean and renewable energy technologies.