Abstract Incorporation of metallic nanoparticles (NPs) in polymer matrix has been used to enhance and control dissolution and release of drugs, for targeted drug delivery, as antimicrobial agents, localized heat sources, and for unique optoelectronic applications. Gold NPs in particular exhibit a plasmonic response that has been utilized for photothermal energy conversion. Because plasmonic nanoparticles typically exhibit a plasmon resonance frequency similar to the visible light spectrum, they present as good candidates for direct photothermal conversion with enhanced solar thermal efficiency in these wavelengths. In our work, we have incorporated ∼3-nm-diameter colloidal gold (Au c ) NPs into electrospun polyethylene glycol (PEG) fibers to utilize the nanoparticle plasmonic response for localized heating and melting of the polymer to release medical treatment. Au c and Au c in PEG (PEG+Au c ) both exhibited a minimum reflectivity at 522 nm or approximately green wavelengths of light under ultraviolet-visible (UV-Vis) spectroscopy. PEG+Au c ES fibers revealed a blue shift in minimum reflectivity at 504 nm. UV-Vis spectra were used to calculate the theoretical efficiency enhancement of PEG+Au c versus PEG alone, finding an approximate increase of 10 % under broad spectrum white light interrogation, and ∼14 % when illuminated with green light. Au c enhanced polymers were ES directly onto resistance temperature detectors and interrogated with green laser light so that temperature change could be recorded. Results showed a maximum increase of 8.9 °C. To further understand how gold nanomaterials effect the complex optical properties of our materials, spectroscopic ellipsometry was used. Using spectroscopic ellipsometry and modeling with CompleteEASE® software, the complex optical constants of our materials were determined. The complex optical constant n (index of refraction) provided us with optical density properties related to light wavelength divided by velocity, and k (extinction coefficient) was used to show the absorptive properties of the materials.
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This content will become publicly available on June 1, 2025
Spectroscopic analysis of lead lanthanum zirconate titanate films using UV-VIS and ellipsometry
Spectroscopic ellipsometry and ultraviolet-visible (UV-VIS) spectrometry were utilized to study the optical properties of ferroelectric lead lanthanum zirconate titanate (PLZT) films. These films were deposited on platinized silicon [Si(100)/ SiO2/TiO2/Pt(111)] substrates using the chemical solution deposition method. Films were annealed at two different temperatures (650 and 750 °C) using rapid thermal annealing. Shimadzu UV-1800 UV-VIS spectrophotometer with a resolution of 1 nm was used to measure the reflectance data in the spectral range of 300–1000 nm with a step size of 1 nm. The bandgap values were determined from the reflectance spectra using appropriate equations. A J.A. Woollam RC2 small spot spectroscopic ellipsometer was used to obtain the change in amplitude (Ψ) and phase (Δ) of polarized light upon reflection from the film surface. The spectra were recorded in the wavelength range of 210–1500 nm at an incident angle of 65°. Refractive index (n) and extinction coefficient (k) were obtained by fitting the spectra (Ψ, Δ) with the appropriate models. No significant changes were observed in the optical constants of PLZT films annealed at 650 and 750 °C. The optical transparency and the strong absorption in the ultraviolet (UV) region of PLZT films make them an attractive material for optoelectronic and UV sensing applications.
more » « less- Award ID(s):
- 1919232
- NSF-PAR ID:
- 10529465
- Editor(s):
- Haasch, Richard; Graham, Dan; Podraza, Nikolas; Shard, Alexander
- Publisher / Repository:
- AIP publishing
- Date Published:
- Journal Name:
- Surface Science Spectra
- Volume:
- 31
- Issue:
- 1
- ISSN:
- 1055-5269
- Page Range / eLocation ID:
- 8
- Subject(s) / Keyword(s):
- Band gap Ferroelectric materials Annealing Reflectance spectroscopy Thin film deposition Optical absorption Optical constants Optical properties UV-visible spectrophotometer
- Format(s):
- Medium: X Other: pdf
- Sponsoring Org:
- National Science Foundation
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