@article {58230, title = {Near-Infrared Spectrally Selective Plasmonic Electrochromic Thin Films}, journal = {Advanced Optical Materials}, volume = {1}, year = {2013}, month = {03/2013}, pages = {215 - 220}, abstract = {

A plasmonic electrochromic effect in which electrochemical doping reversibly modulates near-infrared surface plasmon absorption of aluminium-doped zinc oxide and tin-doped indium oxide nanocrystals is reported. Optical performance, switching kinetics, and cycling durability point to high-performance NIR selective plasmonic electrochromic coatings based on earth-abundant materials.

}, keywords = {aluminum zinc oxide, indium tin oxide, nanocrystal, spectroelectrochemistry, surface plasmon}, doi = {10.1002/adom.201200051}, author = {Guillermo Garcia and Raffaella Buonsanti and Anna Llordes and Evan L. Runnerstrom and Amy Bergerud and Delia J. Milliron} } @article {58229, title = {Regional performance targets for transparent near-infrared switching electrochromic window glazings}, journal = {Building and Environment}, volume = {61}, year = {2013}, month = {03/2013}, pages = {160 - 168}, abstract = {

With building heating and cooling accounting for nearly 14\% of the national energy consumption, emerging technologies that improve building envelope performance have significant potential to reduce building energy consumption. Actual savings from these technologies will depend heavily upon their performance in diverse climate and operational conditions. In many cases, early-stage research can benefit from detailed investigation in order to develop performance thresholds and identify target markets. One example, a dynamic, highly transparent, near-infrared switching electrochromic (NEC) window glazing, is the focus of this investigation. Like conventional electrochromics, the NEC glazing can dynamically tune its optical properties with a small applied voltage. Consequently, the glazing can block or transmit solar heat to reduce cooling or heating loads, respectively. Unlike conventional electrochromics, NEC glazings remain transparent to visible light, causing no adverse effect to daylighting or building aesthetics. This study utilizes the software COMFEN to simulate a broad range of NEC performance levels, for commercial and residential buildings in 16 climate-representative reference cities. These simulations are the basis for identifying performance levels necessary to compete with existing static technologies. These results indicate that energy savings are strongly influenced by blocking-state performance. Additionally, residential applications have lower performance requirements due to their characteristic internal heat gains. Finally, the most dynamic NEC performance level is simulated in competition with high performing static alternatives. Here heating and cooling energy savings range from 5 to 11\ kWh/m2 yr for commercial and 8{\textendash}15\ kWh/m2 yr for residential, in many regions on the order of 10\%.

}, keywords = {Dynamic windows, Electrochromic glazings, NIR-switching, Performance targets, Solar heat gain}, issn = {03601323}, doi = {10.1016/j.buildenv.2012.12.004}, author = {Nicholas DeForest and Arman Shehabi and Guillermo Garcia and Jeffery B. Greenblatt and Eric R. Masanet and Eleanor S. Lee and Stephen E. Selkowitz and Delia J. Milliron} } @article {57807, title = {U.S. energy savings potential from dynamic daylighting control glazings}, journal = {Energy and Buildings}, volume = {66}, year = {2013}, month = {11/2013}, pages = {415-423}, chapter = {415}, abstract = {

Daylighting controls have the potential to reduce the substantial amount of electricity consumed for lighting in commercial buildings. Material science research is now pursuing the development of a dynamic prismatic optical element (dPOE) window coating that can continuously readjust incoming light to maximize the performance and energy savings available from daylighting controls. This study estimates the technical potential for energy savings available from vertical daylighting strategies and explores additional savings that may be available if current dPOE research culminates in a successful market-ready product. Radiance daylight simulations are conducted with a multi-shape prismatic window coating. Simulated lighting energy savings are then applied to perimeter floorspace estimates generated from U.S. commercial building stock data. Results indicate that fully functional dPOE coatings, when paired with conventional vertical daylight strategies, have the potential to reduce energy use associated with U.S. commercial electric lighting demand by as much as 930 TBtu. This reduction in electric lighting demand represents an approximately 85\% increase in the energy savings estimated from implementing conventional vertical daylight strategies alone. Results presented in this study provide insight into energy and cost performance targets for dPOE coatings, which can help accelerate the development process and establish a successful new daylighting technology.

}, keywords = {Clerestories, daylighting, Dynamic prismatic optical elements (dPOE), energy efficiency, Glare, indoor environmental quality, radiance, windows}, doi = {10.1016/j.enbuild.2013.07.013}, author = {Arman Shehabi and Nicholas DeForest and Andrew McNeil and Eric R. Masanet and Jeffery B. Greenblatt and Eleanor S. Lee and Georgeta Masson and Brett A. Helms and Delia J. Milliron} } @booklet {1213, title = {Electro-Responsive Polymer Glazings For Smart Windows With Dynamic Daylighting Control}, year = {2012}, month = {02/2012}, abstract = {

In the context of alarming phenomenon of global warming with harmful consequences such as increased green house gases beyond predictions, the development of advanced energy efficient technologies became of a primary importance. Since the building sector accounts for 39\% of total US primary energy consumption, fenestration can significantly contribute to lowering the energy use for heating, cooling, and lighting. An estimated 9\% reduction in total US building energy use, or 3.47 Q, could be attained by dynamic solar/thermal control and daylighting if these advanced optical technologies were adopted throughout the residential and commercial building sectors. In spite of the great research and engineering efforts in the fast growing area of smart windows, development of glazing devices able to provide efficient, durable, and inexpensive products for dynamic daylight control is in infancy. Like the electrochromic glazings now emerging on the market, microscale, switchable daylight-redirecting glazings have the potential for widespread application if a low-cost, durable coating can be engineered and manufactured with the proper set of attributes.

Here we report on the development of a new technology using smart materials for switchable daylight-redirecting glazings. The proposed system consists in a prismatic optical element (POE) fabricated by micro-imprinting of an elastic redox-active polymer network capable to change its geometry and thereby its optical properties in response to an external stimulus. It is expected that the prismatic optical element reversibly collapses in response to an applied potential, thereby modulating the fraction of light which is redirected. The fabrication of the dynamic prismatic optical element from simulation-driven design to materials synthesis and device integration will be described. Investigation of specto-electrochemical characteristics of the redox-active grating and challenges encountered with respect to electromechanical induced structural changes will be also presented.

}, author = {Georgeta Masson and Rueben Mendlesberg and Irene Fernandez-Cuesta and Stefano Cabrini and Delia J. Milliron and Brett A. Helms and Eleanor S. Lee and Andrew McNeil and Stephen E. Selkowitz} } @article {2974, title = {Achieving high mobility ZnO:Al at very high growth rates by dc filtered cathodic arc deposition}, journal = {Journal of Physics D: Applied Physics}, volume = {44}, year = {2011}, pages = {232003-232007}, chapter = {232003}, abstract = {

Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500{\textendash}1300\ nm thick and highly transparent ZnO\ :\ Al films were grown on glass at rates exceeding 250\ nm\ min-1 while maintaining resistivity below 5 {\texttimes} 10-4\ Ω\ cm with electron mobility as high as 60\ cm2\ V-1\ s-1.

}, doi = {10.1088/0022-3727/44/23/232003}, author = {Rueben J. Mendelsberg and Sunnie H.N. Lim and Yuankun Zhu and Joe Wallig and Delia J. Milliron and Andr{\'e} Anders} } @article {58919, title = {Dynamically Modulating the Surface Plasmon Resonance of Doped Semiconductor Nanocrystals}, journal = {Nano Letters}, volume = {11}, year = {2011}, month = {10/2011}, pages = {4415 - 4420}, abstract = {

Localized surface plasmon absorption features arise at high doping levels in semiconductor nanocrystals, appearing in the near-infrared range. Here we show that the surface plasmons of tin-doped indium oxide nanocrystal films can be dynamically and reversibly tuned by postsynthetic electrochemical modulation of the electron concentration. Without ion intercalation and the associated material degradation, we induce a \> 1200 nm shift in the plasmon wavelength and a factor of nearly three change in the carrier density.

}, keywords = {doping, indium tin oxide, nanocrystal, spectroelectrochemistry, surface plasmon}, issn = {1530-6984}, doi = {10.1021/nl202597n}, author = {Guillermo Garcia and Raffaella Buonsanti and Evan L. Runnerstrom and Rueben J. Mendelsberg and Anna Llordes and Andr{\'e} Anders and Thomas J. Richardson and Delia J. Milliron} }