Subwavelength Plasmonic Color Tuning of Quantum Dot Emission

Abstract

The need to develop new patterning techniques for high-resolution microdisplays becomes paramount with the rapidly emerging popularity of augmented/virtual reality. Localized surface plasmon resonance (LSPR) can be precisely designed for wide spectral tuning of external broadband sources with subwavelength resolution. However, emission shifting of chromophores with LSPR is limited in range due to their narrowband emission. We report an alternative method of producing full-color tunability, by modulating the intensity of red, green, and blue peaks of gradient alloy cadmium-zinc chalcogenide core/shell quantum dots (QDs) using LSPR of Ag nanopillar arrays. Photoluminescence enhancement is largely dependent on the Purcell effect and radiative scattering and is found to be highest when emission coincides with the resonance wavelength. Red, green, and blue subpixels with dimensions of 480, 312, and 225 nm, respectively, can be generated in a single patterning step (equivalent to 24 500 ppi), which far exceeds the tens of micrometers achieved by inkjet printing. This potentially paves the way toward realization of microdisplays with extreme resolution.