Surface-Sensitive Photon Avalanche Behavior Revealed by Single-Avalanching-Nanoparticle Imaging

Avalanching nanoparticles (ANPs) are a new class of lanthanide-based upconverting material demonstrating steep optical nonlinearities with the potential to advance applications ranging from subwavelength bioimaging neuromorphic computing, nanothermometry, and pressure transduction. Here, we use single-nanocrystal imaging uncover design-dependent heterogeneity in ANP threshold intensity (Ith). Quantitative comparisons between distributions Ith shell properties reveal correlations mean values, histogram widths, nanocrystal thickness. Evaluating avalanching behaviors using an established model shell-dependent surface energy transfer shows that variations thickness–and resultant through environment–are likely primary contributor ANP-to-ANP heterogeneity. Further, nanocrystals ?6 nm average thickness show beyond extent expected statistical measurements size variability transmission electron microscopy (TEM). These results provide principal guide for design application ANPs environmental sensing.