Fabrication and application of periodic silver hollow nanorod arrays for enhanced photoluminescence

Abstract

This study examines the optical properties of a periodic silver hollow nanorod array (PSHNA) substrate with varying nanorod heights fabricated using a nanosphere lithography method. Finite element method (FEM) simulations were performed to analyze the absorption spectrum and electric field distribution of the PSHNA substrate. The results revealed localized surface plasmon resonance peaks at approximately 560, 580, and 595 nm for nanorod heights of 250, 350, and 450 nm, respectively. The electric field was found to be strongly localized around the nanorods, confirming the unique properties and enhanced photonic behavior of the PSHNA substrate. By adjusting the etching time of inductively coupled plasma reactive-ion etching, the nanorod heights were controlled at 250 ± 5, 350 ± 9, and 450 ± 13 nm to match the simulation conditions of the FEM. Experimental absorption spectra showed a distinct absorption peak near 595 nm for the PSHNA substrate with a nanorod height of 450 ± 13 nm. Photoluminescence (PL) intensity of the 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) molecules demonstrated a significant enhancement of 14.68-fold for this particular nanorod height. Additionally, time-resolved PL measurements indicated the shortest PL decay time for the PSHNA substrate with a nanorod height of 450 ± 13 nm, coinciding with the PL band for DCJTB. These findings provide valuable insights for designing and optimizing optical devices based on PSHNA structures.