UC Merced

An explanation was sought for unexpected fluorescence spectroscopy results encountered when examining as-synthesized gallium selenide (GaSe) nanoparticles at low temperatures, 20-240 K. Three types of spectroscopy were utilized in the process of gathering data. UV-Vis absorption spectroscopy was employed at room temperature. Static fluorescence spectroscopy was used in the temperature range from room temperature down to 15-20 K and time-resolved fluorescence spectroscopy results were gathered from 21 K to 240 K. The results are consistent with the idea that GaSe nanoparticle nuclei exist in equilibrium with GaSe nanoparticles in the synthesis the Kelley lab commonly uses. These nuclei are non-luminescent at room temperature due to non-radiative losses, but emit strongly at low temperatures, approaching a quantum yield of 1.0 at 21 K.