Research by Carter Bodinger

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Characterizing the Optical Absorbance of PVP Thin Films Containing Gold Nanoparticles with Effective Medium Theory

Student: Carter Bodinger

Major Professor: Dr. Keith Roper

Research Area(s): Nanoscience & Engineering

Background/Relevance

  • Optical materials are being studied for their applications in energy, sensing, and information technologies.

Innovation

  • Being able to model optical response of materials such as noble metals dispersed in optically transparent polymer would allow for better design and integration of these materials.

Approach

  • Refractive index (N) and extinction coefficient (K) data were gathered from literature.
  • PVP containing gold nanoparticles was spun onto BK-7 glass.
  • Maxwell Garnett Effective Medium Theory was used to calculate an effective dielectric function for the film.
  • N,K data were used to calculate theoretical absorption spectra.

Key Results

  • Theoretical absorption peaks occurred at wavelengths  consistent with experimental measurements.
  • Limits exist for the model at a thickness of about 10 nm.

Conclusion

  • A parameter that represents the effects of nanoparticle size on peak location needs to be added to the model.
  • Model validity is dependent on accurate physical thickness measurements.