Bulletin of the American Physical Society
APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014; Denver, Colorado
Session G12: Invited Session: Energy Research and Applications |
Hide Abstracts |
Sponsoring Units: GERA Chair: Rueben Collins, Colorado School of Mines Room: 205 |
Tuesday, March 4, 2014 11:15AM - 11:51AM |
G12.00001: Light-induced defect creation and recombination in organic solar cells Invited Speaker: Robert Street Prolonged exposure to visible, UV and x-ray radiation induces defects in some organic bulk heterojunction solar cells, and the resulting excess recombination reduces the cell efficiency. Optical transitions characteristic of deep localized electronic states are observed by photocurrent spectroscopy and allows the kinetics of defect creation to be measured. The defect creation rate varies greatly with photon energy and saturates after a long exposure. The states are reversible by annealing to about 100C with thermal activation energy of 1.1-1.3 eV. The results suggest that the defects arise from the recombination-induced dissociation of C-H bonds and the migration of the hydrogen to other sites in the polymer. First-principles calculations show that the resulting under-and over-coordinated carbon atoms are deep traps with properties consistent with the measurements. In the absence of light-induced defects, the dominant recombination process is a transition through localized band tail states, which is reflected in the diode forward bias current-voltage characteristics. The diode ideality factor is temperature dependent and related to the band tail slope. [Preview Abstract] |
Tuesday, March 4, 2014 11:51AM - 12:27PM |
G12.00002: Prospects of Omnidirectional Substrates for Light Trapping Invited Speaker: Teri Odom Nanostructured substrates are promising for light trapping in photovoltaic devices because they have the potential to manage and direct light absorption and scattering. Whether these structures should be periodic or randomly arranged is under some debate, although most texturing in inorganic devices has no short or long-range order. This talk will describe how different types of nano-textured substrates can result in broadband absorption over visible and near-infrared ranges. We will discuss different strategies to generate subwavelength features with moir\'{e} patterns, high rotational symmetries, and wrinkled features. The potential of these omnidirectional substrates in organic photovoltaics will be described. [Preview Abstract] |
Tuesday, March 4, 2014 12:27PM - 1:03PM |
G12.00003: Understanding and Optimizing Bulk Thermoelectric Materials Invited Speaker: Andrew May Thermoelectric materials research continues to expand due to the need to increase energy conversion efficiencies, as well as the expanding role of thermoelectrics in niche applications. I will review several examples demonstrating the successes and limitations of semi-classical models of electron and phonon transport in the study of bulk thermoelectric materials. Single band models provide a simple starting point for analysis and optimization, and can facilitate the development of more physically-accurate models. The importance of identifying intrinsically favorable electronic structures will be demonstrated with La$_{3-x}$Te$_{4}$, where a heavy-band/light-band configuration leads to desirable properties. Using other chalcogenides and intermetallics as examples, I will also discuss the importance of phonon dispersions and scattering mechanisms, and how they can provide insight for materials exploration efforts. Research supported by the U. S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. [Preview Abstract] |
Tuesday, March 4, 2014 1:03PM - 1:39PM |
G12.00004: An Aqueous Based Route to Fabricating 3-D Solid-State Lithium-Ion Batteries Invited Speaker: Derek Johnson |
Tuesday, March 4, 2014 1:39PM - 2:15PM |
G12.00005: Quantum Confined Semiconductors for High Efficiency Photovoltaics Invited Speaker: Matthew Beard Semiconductor nanostructures, where at least one dimension is small enough to produce quantum confinement effects, provide new pathways for controlling energy flow and therefore have the potential to increase the efficiency of the primary photon-to-free energy conversion step. In this discussion, I will present the current status of research efforts towards utilizing the unique properties of colloidal quantum dots (NCs confined in three dimensions) in prototype solar cells and demonstrate that these unique systems have the potential to bypass the Shockley-Queisser single-junction limit for solar photon conversion. The solar cells are constructed using a low temperature solution based deposition of PbS or PbSe QDs as the absorber layer. Different chemical treatments of the QD layer are employed in order to obtain good electrical communication while maintaining the quantum-confined properties of the QDs. We have characterized the transport and carrier dynamics using a transient absorption, time-resolved THz, and temperature-dependent photoluminescence. I will discuss the interplay between carrier generation, recombination, and mobility within the QD layers. A unique aspect of our devices is that the QDs exhibit multiple exciton generation with an efficiency that is $\sim$ 2 to 3 times greater than the parental bulk semiconductor. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700