Date of Award
Spring 1-1-2015
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical, Computer & Energy Engineering
First Advisor
Wounjhang Park
Second Advisor
Xiaobo Yin
Third Advisor
Garret Moddel
Fourth Advisor
Sean Shaheen
Fifth Advisor
Milos Popovic
Abstract
This thesis studies the application of plasmonics in solar energy conversion and near field thermal energy harvesting.
The efficiency of semiconductor solar cell is limited by the inability of absorbing photons with energy below the bandgap. By designing plasmonic nanograting with resonance at the absorption edge, ~10% overall absorption improvement is achieved. Both localized and propagating surface plasmon modes are observed in the device. Their interaction, and the influence on overall solar cell absorption performance are studied in details.
In addition, this thesis studies the upconversion materials which can convert unabsorbed near infrared photons by semiconductor solar cells into well absorbed visible photons. By tuning the surface plasmon resonance at the upconversion frequency with silver nanograting structure, the photoluminescence of upconversion material can be improved by 39-fold maximum. The rate equation analysis reveals that the improvement is attributed to roughly 3-fold absorption enhancement and 2-fold energy transfer enhancement with plasmonics.
This thesis also explores the application of plasmonics to enhanced near field thermal radiation harvesting. I designed metamaterial to excite the spoof surface plasmon in the terahertz frequency for strongly enhanced thermal radiation. The FDTD simulation developed from the fluctuation electrodynamics demonstrates several hundredfold enhancement of thermally excited electromagnetic energy in the near field.
Recommended Citation
Lu, Dawei, "Application of Plasmonics in Energy Harvesting" (2015). Electrical, Computer & Energy Engineering Graduate Theses & Dissertations. 116.
https://scholar.colorado.edu/ecen_gradetds/116