Advances in plasmonic enhanced luminenscence of upconversion nanoparticles

Upconversion nanoparticles (UCNPs) have widely potential applications in photocatalytic cells, bioimaging, and optical probes. However, the current upconversion efficiency is often insufficient for practical use in these applications. One promising approach to enhance the efficiency is by integrating plasmon nanostructures, which exploit the local surface plasmon resonance (LSPR) effect to amplify the electric field strength and radiation decay rate. This review explores the processes involved in plasmon-enhanced upconversion, including excitation, emission, energy transfer, and non-radiative transitions. It investigates how the shape, size, and structure of plasmonic nanostructures affect the LSPR effect. The review also examines the influence of factors like spacer thickness, excitation conditions, and spectral overlap on the dynamics of metal-enhanced upconversion.