Multifaceted Effects of the Dielectric Component within Plasmon-Assisted Light-Emitting Structures

Plasmon-enhanced photoluminescence of molecular probes and semiconductor nanocrystals is a rapidly developing field that promises enhanced sensitivity in chemical and biomedical analyses, as well as higher efficiency of light-emitting devices and single-photon sources. The dielectric component, or spacer, is typically used to control the distance between the emitter and the plasmonic nanoparticle in order to decrease undesirable nonradiative energy transfer to the metal and achieve high enhancement efficiency. While most research focuses on the shape and organization of the plasmonic nanoparticles, less attention is given to the role of the dielectric component in plasmon-enhancing structures. Meanwhile, the dielectric shell or environment critically modulates near-field enhancement, far-field scattering, charge and energy exchange between the emitter and the plasmonic structure, and the general environmental stability of the structure. In this review, we discuss all mentioned topics and therefore consider both the optical and chemical influence of the widely used spacers and dielectric layers on plasmon-enhanced photoluminescence efficiency. Investigating the role of individual components in plasmon-assisted light-emitting structures is critical for optimizing device performance and for advancing the integration of plasmonic architectures in optoelectronic and sensing applications. This review challenges the passive interpretation of dielectrics, revealing them as one of the key players in plasmonic structures, mediating field enhancement, emission dynamics, and chemical stability simultaneously.