Comparative investigation of the optical spectroscopic and thermal effect in Nd3+-doped nanoparticles

Abstract

Nd³⁺-doped nanoparticles involving 808 nm excitation hold great promise in various biomedical applications, such as bioimaging, biodetection, theranostics and optogenetics. Here we present the synthesis and characterization of core–multishell Nd³⁺-doped nanoparticles displaying excellent optical properties. We systematically studied the influence of doping concentration, nanostructure design, excitation wavelength and size effect on the upconversion luminescence of Nd³⁺-doped nanoparticles. Remarkably, the emission intensity of optimized nanoparticles with 808 nm excitation is three times higher than the emission intensity of those with 980 nm excitation. Surprisingly, the optical profiles of Nd³⁺-doped nanoparticles strongly depend on the excitation wavelengths. The dominant effect responsible for the emission intensity difference and the energy transfer mechanism upon different excitation wavelengths are investigated. Interestingly, the heavily Nd³⁺-doped nanoparticles not only display efficient upconversion luminescence, but also are able to convert the excitation source to heat under a single 808 nm excitation source. Importantly, these efforts will lead to Nd³⁺-doped nanoparticles with unprecedented optical and thermal properties that will have broad utility in fundamental research and technological applications.