Enhanced photoluminescence of DCJTB by silver nanohole arrays with ring-shaped silver nanoparticles over hyperbolic metamaterials

In this study, a novel approach for fabricating silver nanohole arrays (AgNAs) on silicon/hyperbolic metamaterial (Si/HMM) substrates is described. This approach involves the use of fixed-size plastic nanoparticles combined with reactive-ion etching, followed by decoration with silver nanoparticles (AgNPs) around the edges of the Ag nanoholes. The HMM structure is composed of six pairs of alternating layers of silver and silicon dioxide (Ag/SiO2). Herein, the interaction of the localized surface plasmon resonance (LSPR) is investigated by the analysis of photoluminescence (PL) responses of 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) molecules over the AgNAs on the Si/HMM substrates. Both configurations, i.e., with and without ring-shaped AgNPs, are investigated extensively by a combination of experimental measurements and numerical simulations. The substantially enhanced PL for the proposed substrates can be attributed to increased light absorption, leading to the fine-tuning of surface-enhanced electromagnetic fields. Notably, the PL intensity of DCJTB is significantly enhanced (16.4 times) in comparison with that of the reference substrate. Concurrently, the PL lifetime is reduced by 49.45% (0.91 ns–0.46 ns). These results underscore the transformative potential of these enhanced substrates in reshaping the landscape of sensing platforms. The enhanced PL response coupled with the precisely tunable LSPR effects demonstrates promise for innovative applications in optical and photonic technologies.