Energy Transfer and Avalanche Upconversion of NdxY1−xVO4 Nanocrystals

Abstract

We explore Nd concentration and excitation power dependences of the avalanche upconversion of NdxY1–x VO4 (x = 0–1) nanocrystals with uniform size and shape. The avalanche threshold power caused by the near-resonant energy transfer between 4F5/2 → 4I13/2 and 4F5/2 → 2G9/2 significantly decreases as the Nd3+ concentration increases. The off-resonant energy transfer between 4F5/2 → 4I13/2 and 4F5/2 → 4G11/2 in the strong excitation regime leads to apparent broadening on the blue-side of the upconversion spectrum of NdVO4 nanocrystals.