Fig. 1: Material characterization and spectral characterization of a single ECS nanowire.
From: Self-optimized single-nanowire photoluminescence thermometry
a SEM image of a single nanowire on a substrate with parallel grooves (a, scale bar: 100 µm). b HRTEM of ECS single crystal (scale bar: 10 nm) and c the lattice diffraction pattern. PL properties of an ECS nanowire in the NIR-IIB bio-window pumped by 980 nm diode laser. d PL spectra from 4 to 500 K. e Comparison of PL spectra at 4 K and room temperature showing temperature-dependent population change and the corresponding PL spectral changes forming the foundation of temperature sensing mechanism. f Spectrum of a single Stark sub-peak originated from 4I13/2 levels at 4 K. g Power dependence of integrated emission intensity originated from 4I13/2 levels at 4 K and the room temperature
