A Generalized Approach to Photon Avalanche Upconversion in Luminescent Nanocrystals

Abstract

Photonavalanching nanoparticles (ANPs) exhibit extremelynonlinearupconverted emission valuable for subdiffraction imaging, nanoscalesensing, and optical computing. Avalanching has been demonstratedwith Tm3+-, Pr3+-, or Nd3+-dopednanocrystals, but their emission is limited to a few wavelengths andmaterials. Here, we utilize Gd3+-assisted energy migrationto tune the emission wavelengths of Tm3+-sensitized ANPsand generate highly nonlinear emission from Eu3+, Tb3+, Ho3+, and Er3+ ions. The upconversionintensities of these spectrally discrete ANPs scale with nonlinearityfactor s = 10-17 under 1064 nm excitationat power densities as low as 7 kW cm(-2). This strategyfor imprinting avalanche behavior on remote emitters can be extendedto fluorophores adjacent to ANPs, as we demonstrate with CdS/CdSe/CdScore/shell/shell quantum dots. ANPs with rationally designed energytransfer networks provide the means to transform conventional linearemitters into a highly nonlinear ones, expanding the use of photonavalanching in biological, chemical, and photonic applications.