Dye sensitized solar cells (DSSCs) are third generation solar devices that have rapidly emerged in the past decade as an inexpensive alternative to silicon solar cells. While the low cost of fabrication processes make DSSCs highly promising, the poor light absorption and inherent low efficiencies (< 10%) of current devices have hindered successful market entry. Plasmon resonances, which are the collective oscillations of the conduction electrons, in noble metal nanostructures can be engineered by modulating their geometry, dimensions, and composition to generate intense light scattering and electromagnetic near-fields surrounding their surface. Plasmons in metal nanostructures when coupled with light harvesting organic dyes can significantly amplify the dye optical absorption and carrier generation capabilities. This proposal aims to develop a new paradigm of bimetallic plasmonic nanostructures to understand, control, and optimize light harvesting in DSSCs. By combining wet-chemical synthesis, controlled surface engineering, electrodynamics simulations, device physics, and ultrafast optics, plasmon-enhanced DSSCs will be constructed and their photocurrent efficiencies will be significantly enhanced.
Non-Technical Explanation of the Project's Signficance
Nanoscale metal-molecule hybrid interfaces are ubiquitous in energy conversion and energy storage, as well as in optoelectronic devices. The information learned from this project will provide fundamental scientific insights of the optical properties at the organic/inorganic interface and how that influences optically-induced electron transport processes. The proposed research efforts will also broadly impact the future infrastructure of both portable and stationary energy conversion systems. High efficiency plasmonic DSSCs will ultimately enable inexpensive sustainable energy systems that can be developed and implemented in third-world countries. For example, cheap and reliable solar electricity, solar-thermal convertors for use as space heaters, solar driven motors for niche applications in remote villages, and solar driven small vehicles which will ultimately reduce greenhouse gas emissions. These devices will form a new platform for a range of light harvesting devices including photoelectrochemical cells, optical sensors, and solar-energy-conversion systems.
Activities to Broaden Participation of Underrepresented Groups in Engineering
The proposed research is expected to broaden the participation of underrepresented minorities (URMs) in STEM education through active participation of graduate, undergraduate and K-12 students in the research. The PI will continue to involve URM undergraduates in her research efforts. The project will lead to development of a lab module in an existing class, and students will visit local colleges with high URM population and demonstrate DSSC fabrication with berry juices. The PI will also participate in mature outreach activities to promote K-12 education particularly among URMs. The PI currently co-leads the Boy Scouts of America Engineering Explorers program at Vanderbilt and ~67% of the high school student participants are URMs. The PI also currently participates and will continue to contribute to the Vanderbilt Summer Academy (VSA) where middle school students (50% URM) perform hands on nanoscience experiments. VSA students performed synthesis and characterization of gold nanostructures of variable shapes and sizes in the PI's lab.
This research has been funded through the Broadening Participation Research Initiation Grants in Engineering solicitation, which is part of the Broadening Participation in Engineering Program of the Engineering Education and Centers Division.
The research is also funded through the Experimental Program to Stimulate Competitive Research (EPSCoR), which is part of the Office of International and Integrative Activities.