Purcell Factor: A Tunable Metric for Plasmon-Coupled Fluorescence Emission Enhancements in Cermet Nanocavities

Abstract

We demonstrate an important approach to correlate Purcell factor (PF) and surface plasmon-coupled emission (SPCE) enhancements with the use of finite-difference time-domain (FDTD) simulations and time-correlated single-photon counting (TCSPC) studies of a radiating dipole in cermet nanocavities. We observed >50-fold fluorescence enhancement with high directionality and polarization of Rhodamine 6G (Rh6G) emission trapped in the nanocavity created between the titanium-based ceramic nanoparticle and metallic silver thin film. Compositional variation with hybrid nanoparticles, TiC0N1 (TiN), TiC0.5N0.5 (TiCN), and TiC1N0 (TiC), brought about enhanced PFs and tunable fluorescence enhancements that were used for mobile-phone-based detection of tryptophan with nanomolar sensitivity. We hope that this study opens the door to next-gen plasmonics with the ability to tune and enhance the hot-spot electromagnetic field intensity of alternative plasmonic materials, as hybrid synergy spacers in the SPCE platform.

Ag‐CNT Architectures for Attomolar Dopamine Detection and 100‐Fold Fluorescence Enhancements with Cellphone‐Based Surface Plasmon‐Coupled Emission Platform

“…In this context, we have pioneered the engineering of spacer and cavity materials on SPCE substrate for tunable fluorescence enhancements. Our earlier work on one‐minute spacer engineering with metallic nanoparticles, low‐dimensional carbon substrates, bio‐spacers, magnetic graphene nanocomposites and ceramic nanomaterials for various applications such as femtomolar sensing of organic moiety and picomolar detection of cardiac biomarker has resulted in a significant breakthrough in the next‐gen plasmonics arena. Alternative spacers were reported to show low fluorescence enhancements compared to carbon and metal nanomaterials…”

Chemiplasmonics for high-throughput biosensors

“…Although many previous studies explained the emission enhancements through the MEF model, changes in the spectral features, such as in Figure 1A, were partly ignored. 8,9,12,13,22,23 While the emission spectrum of RhB on 25 nm Ag required a two-peak fit, at least three to four peaks were necessary to fit the emission spectrum of RhB on Ag/ C 60 layers. This important fact is also reflected in Figure 2A-C, which show fluorescence microscope images of RhB coated on bare glass, 25 nm Ag, and 25 nm Ag/20 nm C 60 .…”

Modifying magnetic dipole spontaneous emission with nanophotonic structures

“…In the recent years the outstanding progress in the development of nanoantennas enabling accelerated spontaneous emission has been witnessed. Usually, such antennas incorporate plasmonic nanoparticles , in which the Purcell effect originates from the electric response of the nanostructure. However, enhancement of MD emission requires alternative nanoantennas design supporting magnetic resonances .…”