Harvesting Dual-Wavelength Excitation with Plasmon-Enhanced Emission from Upconverting Nanoparticles

Abstract

We demonstrate dual-wavelength (1210 and 1520 nm) excitation of upconverter nanoparticles (Er-doped nanoparticles) with plasmon-enhanced emission. Gold nanorods of 25 nm diameter with resonances at 808 nm and at 980 nm selectively enhance the upconversion emission of 2% erbium-doped NaYF4 nanoparticles at 808 nm and at 980 nm. No upconversion is seen for 1210 nm excitation alone, and 1520 nm excitation alone provides lower upconversion. The sequential 1520 and 1210 nm absorption yields the most upconversion, and the power dependence of emission supports the sequential absorption mechanism. This provides a promising avenue for harvesting from the two strongest infrared bands of the solar spectrum with selective emission tuned to either the Si or GaAs band gap.