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.
Conclusions
- 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.