Plasmonic nanodiscs on vanadium dioxide thin films for tunable luminescence enhancement

We propose an alternative method to dynamically tune luminescence enhancement in the near infrared spectral range using noble metal nanostructures on top of phase change material vanadium dioxide (VO₂) thin films. The VO₂ phase change is used to tune the nanodisc plasmon resonance providing a luminescence modification mechanism. We employ a model to calculate the emission of quantum emitters, such as dye molecules, in hybrid systems comprising single silver (Ag) nanodiscs on top of a thin layer of VO₂. The model considers different dipole orientations and positions with respect to the nanostructure-VO₂ film and determines the degree of observable luminescence modification. In the NIR spectral region, the observable photoluminescence of Alexa Dyes in the hybrid systems at room temperature is enhanced by more than a factor of 2.5 as compared to the same system without plasmonic particles. An additional photoluminescence enhancement by more than a factor of 2 can be achieved with the Ag nanodisc-VO₂ film systems after the phase transition of the VO₂. These systems can be used for tunable luminescence modification and for compensation of thermally induced luminescence quenching. Through optimization of the Ag nanodisc-VO₂ film system, luminescence enhancements of up to a factor of 4 can be seen in the metallic VO₂ compared to the semiconducting phase and would therefore compensate for a thermal quenching of up to 70% between room temperature and 70° C, rendering the hybrid systems as promising candidates for improved photon management in optoelectronic devices where elevated temperatures minimize the efficiencies of such devices.