Evaporation of levitating microdroplets containing luminescent Gd2O3:Nd3+ nanoparticles (also with Fe-Co nanoparticles)

Description

Microdroplets of suspension were levitated in a linear quadrupole trap and studied as described e.g. in Y. Shopa et al., JQSRT 296 (2023). The suspended phase consisted of nanoparticles of Gd2O3:Nd3+ of several sizes and concentrations. In a few experiments, Fe-Co nanoparticles of ~1 micrometre diameter were also added. The continuous phase consisted of diethylene (2EG) and tetraethylene (4EG) glycols as well as dimethyl sulfoxide (DMSO). Experiments with droplets of pure liquids and suspensions of only Fe-Co nanoparticles were performed for comparison. The data is divided into the folders correspondingly. Luminescence was excited with an 806 nm diode laser (CW, ~1.5 W). A group of 6 luminescence lines were visible in IR: 879, 892, 894, 911, 927, and 942. We also followed the temporal evolution of several lines in scattering at the right angle (usually 806 nm (IR laser) and 662 nm (additional red laser)). Sometimes also 443, 523, 631, 650, 772, 786 and 853 nm (back-light LEDs, non-coherent parts of laser lines and others of immediate interest): files *-Spectra.csv, where * (in hh_mm_ss format) always denotes the time of measurement file creation. Simultaneously the shadow image of the droplet was recorded (non-coherent light, 631 nm LED). The droplet radius was measured by fitting an ellipse to the shadow edge. The ellipse parameters temporal evolution are stored in *-Shadow.pdf files: time, mean diameter (mean of the ellipse axes), long axis rotation, X and Y of the centre, long and short axis, border length, X and Y of “the centre of mass” of the border, fitting error. The microdroplet's vertical position was stabilised with a DC field. The corresponding voltage variation and other stabilisation system parameters are stored in *.csv files: KeyStab: 0 – stabilisation off, 2 – on, k_PID – proportionality parameter of the software voltage regulator, freq – trapping AC field frequency. In some cases, partially concurrently, light was collected at a right angle with a PMT for the green 512 or 806 nm laser. The photon count rate is stored in *-CRM.csv files. Time stored in corresponding files was synchronised. The "Laser on/off" pertains to the 806 nm laser. Further details can be found in the readme.txt files in the corresponding folder. (No)_th_spectrum.csv represents the ith recorded spectrum from the corresponding experiment. The parameters of sample DI119 can be found in the paper cited above. The parameters of samples DI163 and DI230 can be found in the .ppt files in the root directory.

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