A Generalized Approach to Photon Avalanche Upconversion in Luminescent Nanocrystals.

Skripka, Artiom; Lee, Minji; Qi, Xiao; Pan, Jia-Ahn; Yang, Haoran; Lee, Changhwan; Schuck, P James; Cohen, Bruce E et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Photon avalanching nanoparticles (ANPs) exhibit extremely nonlinear upconverted emission valuable for subdiffraction imaging, nanoscale sensing, and optical computing. Avalanching has been demonstrated with Tm<sup>3+</sup>-, Pr<sup>3+</sup>-, or Nd<sup>3+</sup>-doped nanocrystals, but their emission is limited to a few wavelengths and materials. Here, we utilize Gd<sup>3+</sup>-assisted energy migration to tune the emission wavelengths of Tm<sup>3+</sup>-sensitized ANPs and generate highly nonlinear emission from Eu<sup>3+</sup>, Tb<sup>3+</sup>, Ho<sup>3+</sup>, and Er<sup>3+</sup> ions. The upconversion intensities of these spectrally discrete ANPs scale with nonlinearity factor <i>s</i> = 10-17 under 1064 nm excitation at power densities as low as 7 kW cm<sup>-2</sup>. This strategy for imprinting avalanche behavior on remote emitters can be extended to fluorophores adjacent to ANPs, as we demonstrate with CdS/CdSe/CdS core/shell/shell quantum dots. ANPs with rationally designed energy transfer networks provide the means to transform conventional linear emitters into a highly nonlinear ones, expanding the use of photon avalanching in biological, chemical, and photonic applications.