Study of emissivity dependence upon concentration in CdTe quantum dots

Benjamin S. Rinehart, Matthieu Martin, Caroline G.L. Cao

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Due to their unique optical properties, quantum dots (QDs) have received a great deal of interest for their potential applications, such as in quantum computing, photovoltaic cells, and electronics. With such increased usage, the effect that altering QD concentration has on optical properties of the solution should be explored. Characterization of the emissivity of CdTe QDs as a function of concentration was conducted on three commercially available CdTe QDs. All have optimal absorption around 400-500 nm with peak emission wavelengths at 530 nm, 550 nm, and 570 nm, respectively. The QDs were suspended in an aqueous solution at 13 different concentrations ranging from 0.37 mg/ml to 10 mg/ml. The samples were excited at room temperature by a 50 mW diode laser emitting at a central wavelength of 405 nm and the fluorescence of the QDs was measured with a free-space CCD spectrometer. The measured spectra showed a general redshift in peak emission wavelength with increasing concentration. A +6.12 nm per mg/ml shift for the 530 nm QDs was observed when a linear fit with a coefficient of determination (R-squared) of 0.96 was applied. The 550 nm QDs and the 570 nm QDs showed a +8.70 nm per mg/ml shift (R-squared=0.94) and a +10.27 nm per mg/ml shift (R-squared=0.97), respectively. The redshift is attributed to a Föster resonance energy transfer (FRET) which causes energy transfer between two light-sensitive molecules.

Original languageEnglish (US)
Title of host publicationBehavior and Mechanics of Multifunctional Materials and Composites 2015
EditorsNakhiah C. Goulbourne
ISBN (Electronic)9781628415353
StatePublished - 2015
Externally publishedYes
EventBehavior and Mechanics of Multifunctional Materials and Composites 2015 - San Diego, United States
Duration: Mar 9 2015Mar 11 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceBehavior and Mechanics of Multifunctional Materials and Composites 2015
Country/TerritoryUnited States
CitySan Diego


  • Fluorescence
  • Forster Resonance energy transfer
  • Quantum dots
  • Red-shift
  • Spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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