Fast and inexpensive emission-time in-situ setup for upconversion nanoparticle characterization

In this work, a straightforward analytical approach is presented for the evaluation of the entire time-resolved emission spectrum of Er3+-doped upconversion nanoparticles (UCNP) by the acquisition of bidimensional emission wavelength-time signals. Employing diffractive optics and fast optomechanical sweeping, the entire emission wavelength-time matrix (EtM) of UCNP is registered. An optic fibre probe allows the measurement of micrometric-size domains in surfaces, either in solid form or in suspension. Further chemometric analysis was also performed to gain further insight into the behaviour of the emission bands and their corresponding time curve profiles. To show the applicability of the developed procedure, changes either in the emission spectrum or the time behaviour by external perturbations were monitored and EtM at different temperatures was acquired as a proof of concept. The results demonstrated the effectiveness of the proposed procedure in obtaining fast and highly informative images and enlightening knowledge about the phosphorescence-based system.