Harvesting Dual-Wavelength Excitation with Plasmon-Enhanced\nEmission from Upconverting Nanoparticles

Abstract

We\ndemonstrate dual-wavelength (1210 and 1520 nm) excitation of upconverter\nnanoparticles (Er-doped nanoparticles) with plasmon-enhanced emission.\nGold nanorods of 25 nm diameter with resonances at 808 nm and at 980\nnm selectively enhance the upconversion emission of 2% erbium-doped\nNaYF₄ nanoparticles at 808 nm and at 980 nm. No upconversion\nis seen for 1210 nm excitation alone, and 1520 nm excitation alone\nprovides lower upconversion. The sequential 1520 and 1210 nm absorption\nyields the most upconversion, and the power dependence of emission\nsupports the sequential absorption mechanism. This provides a promising\navenue for harvesting from the two strongest infrared bands of the\nsolar spectrum with selective emission tuned to either the Si or GaAs\nband gap.