Plasmon–exciton coupling in two-dimensional materials: fundamentals and applications in nanosensors

Purpose The purpose of this study is to critically review the fundamentals, theoretical frameworks, experimental advances and sensor applications of plasmon–exciton coupling in two-dimensional (2D) materials. This review aims to elucidate how hybrid light–matter interactions at the nanoscale can be engineered to enhance sensing performance while addressing the controversies surrounding coupling regimes and their practical relevance. Design/methodology/approach A comprehensive literature survey of over 120 peer-reviewed articles was conducted, integrating studies in classical electrodynamics, quantum optics and ab initio simulations with experimental results from both weak and strong coupling regimes. The review analyzes the underlying mechanisms of plasmon–exciton interactions, discusses the coupled oscillator and quantum models and evaluates their predictive capability for realistic sensor design. Special attention is given to comparative analyses of reported nanosensor implementations, highlighting their operational principles, sensitivity limits and the influence of device geometry, coupling strength and excitonic material properties. Findings Plasmon–exciton coupling in 2D materials enables remarkable field confinement and exciton resonance modulation, leading to substantial enhancement in photoluminescence, energy transfer and absorption-based sensing. Strong coupling has been demonstrated at room temperature, with Rabi splittings up to 170 meV and even ultrastrong coupling (g/ω > 0.15) achieved via metasurface “hotspot” engineering. While proponents argue that plexcitonic sensors can surpass conventional plasmonic sensors through bidirectional spectral shifts and quantum-noise mitigation, skeptics highlight losses, fabrication challenges and limited reproducibility. Emerging strategies, including multimode coupling, polariton-assisted energy transport and quantum modeling, indicate promising pathways toward highly sensitive, multiplexed sensing platforms. Originality/value This review provides a rigorous, up-to-date synthesis that connects the fundamental physics of plasmon–exciton coupling with nanosensor applications. By critically evaluating theoretical models, experimental evidence and competing viewpoints, it establishes a framework for rational sensor design and identifies key open challenges, such as scalability, loss management and the practical impact of strong coupling on detection limits.