Synthesis and Characterization of CdSe Quantum Dots (NNCI)

This lab introduces students to the synthesis and characterization of Cadmium Selenide semiconductor quantum dots to demonstrate size-dependent physical properties. Using a kinetic growth method involving surfactant chemistry, students produce nanoparticles of varying sizes by controlling reaction times and then characterize their samples using UV-VIS absorption spectroscopy. Through this process, they observe how the confinement of electrons affects optical properties, leading to measurable shifts in color. Students learn to apply the quantum mechanical particle-in-a-box model to estimate particle size from spectral data, gaining hands-on experience with concepts like band gaps, excitons, the Bohr radius, and the transition between molecular and bulk material behavior.

Nanotechnology Materials Science Quantum Dots CdSe Cadmium Selenide UV-VIS Spectroscopy Spectrophotometer Semiconductor Band Gap Particle-in-a-box Nanoparticles Kinetic Growth Fluorescence Exciton Bohr Radius Nanocrystals Surfactant Chemistry AP Chemistry AP Physics Quantum Mechanics

Uploaded by demo on 2026-07-19 · ready · Other · Original source ↗

Files: QD_Synthesis_Blake_TG.pdf · NSF_ATE_provenance.txt

Readiness checks

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Latest report — 2026-07-19 19:39

Readiness report

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This lab is a wet-chemistry and spectroscopy exercise designed for advanced high school or early undergraduate students to synthesize Cadmium Selenide (CdSe) quantum dots and characterize their size-dependent optical properties. Students use a kinetic growth method involving organometallic precursors in a surfactant-based environment to produce nanocrystals at varying time intervals. The lab concludes with UV-VIS absorption spectroscopy to correlate the observed color shifts (red/blue shifts) with the particle-in-a-box quantum mechanical model.

Spectroscopy Instrumentation and Software

The lab is heavily dependent on specific legacy hardware and software for data collection.

  • Spectrometer Hardware: The instructions specify the Ocean Optics Red Tide USB650 UV-VIS spectrometer, with the USB2000 or USB4000 cited as alternatives. These models have largely reached end-of-life (EOL) status and have been superseded by newer Ocean Insight (formerly Ocean Optics) models. Connectivity relies on USB-A interfaces and specific fiber optic cable assemblies.
  • SpectraSuite Software: The lab requires Ocean Optics "SpectraSuite" software installed on a laboratory computer to interface with the spectrometer. This software is legacy and may not be compatible with modern operating systems (Windows 10/11) without specific legacy drivers or virtualization. Newer software like OceanView may require manual translation of the lab’s step-by-step instructions.
  • Cuvettes: Standard cuvettes compatible with the spectrometer’s wavelength range (UV-VIS) are required.

Chemical Reagents and Safety Equipment

The synthesis requires specific precursors that may be subject to increasing environmental and safety regulations.

  • Cadmium Oxide (CdO): A primary precursor. Cadmium compounds are highly toxic and strictly regulated. Future availability in educational settings may be restricted.
  • Selenium Dioxide (SeO₂): Highly toxic by inhalation or ingestion.
  • 1-octadecene (ODE): Used as a high-boiling-point solvent. The guide warns that vapor should not be inhaled.
  • Myristic Acid: Used as a surfactant.
  • Hexane or Decane: Used as solvents for the final quantum dot solutions.
  • Mercury Thermometer (400°C): The procedure specifically lists a "400°C Hg thermometer." Mercury thermometers are being phased out in many educational institutions due to spill hazards; a high-temperature digital thermocouple is a necessary modern replacement but is not described in the original text.
  • Fume Hood: Absolute requirement for the synthesis due to the toxicity of cadmium and selenium vapors.

Digital Resources and URLs

Several URLs provided for background information, images, and software are likely to experience "link rot" over time.

  • SpectraSuite Download: www.oceanoptics.com/products/spectrasuite.asp (Legacy link).
  • IBM Image Gallery: http://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV1003.html (Reference for the IBM xenon atom "logo" image).
  • NNIN/NNCI Portal: www.nnin.org (The organization has transitioned to NNCI, and site structures have changed).
  • University Research Links: Links to the University of Wisconsin (mrsec.wisc.edu) and University of Ghent (lcp.elis.ugent.be) for supplemental images and synthesis theory.

Physical Materials and Labware

  • Heating Mantle and Controller: Required to reach and maintain high temperatures (above 200°C) for the reaction.
  • Three-Necked Round Bottom Flask: Required for the synthesis to allow for a thermometer, precursor injection, and sampling via septa.
  • Septa: Specialized rubber stoppers for the flask that allow syringe/pipette access while maintaining an controlled environment.
  • UV Light Source: A UV lamp or LED flashlight is required to visualize the fluorescence of the samples.