Date of Project
College of Arts and Sciences
Dr. Patrick Holt
CdSe molecules are semiconducting nanocrystals that absorb visible light and emit broad wavelengths of light in response. They utilize electromagnetic radiation not only for emitting broad wavelengths of visible light, but for fluorescence, conducting electricity, and vibrational relaxation. The Thermal Lensing technique (TL) can be used to study the lifetimes of the excited state transitions and the various nonradiative processes molecules can undergo in order to better understand the excited state dynamics of semiconducting nanocrystals, and in turn, better understand how these molecules may be applied in solar cells, lasers, and fluorescence labeling. Using known methods, four samples of CdSe semiconducting nanocrystals were synthesized and colloidally suspended in a solution of octadecene. Their UV-Visible absorption spectra were obtained to determine the maximum visible absorption of each sample. The radii of the nanocrystals were calculated from the UV-Visible data, and then TL spectroscopy was performed to determine the lifetime of the excited states (τ). The fluorescence quantum efficiency (η), and fraction thermal load (φ) were meant to be determined, but due to limited data, were not determined successfully.
Bledsoe, Charles, "The Quantum Efficiency of CdSe Semiconducting Nanocrystals" (2015). Undergraduate Theses. 3.