Golden, CO, United States

National Renewable Energy Laboratory

www.nrel.gov
Golden, CO, United States

The National Renewable Energy Laboratory , located in Golden, Colorado, is the United States' primary laboratory for renewable energy and energy efficiency research and development. The National Renewable Energy Laboratory is a government-owned, contractor-operated facility, and is funded through the U.S. Department of Energy . This arrangement allows a private entity to operate the lab on behalf of the federal government under a prime contract. NREL receives funding from Congress to be applied toward research and development projects. NREL also performs research on photovoltaics under the National Center for Photovoltaics. NREL has a number of PV research capabilities including research and development, testing, and deployment. NREL's campus houses several facilities dedicated to PV research. Wikipedia.


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Patent
Battelle and National Renewable Energy Laboratory | Date: 2017-01-25

A method of processing a mixture of heated vapors, at least two of which substantially differ in polarity from each other, the method comprising directing said mixture of heated vapors at a temperature of at least 150 C. through a hydrophobic or hydrophilic mesoporous membrane comprising a mesoporous coating of hydrophobized or hydrophilized metal oxide nanoparticles, respectively, wherein the hydrophobic mesoporous membrane permits passage of one or more hydrophobic heated vapors and blocks passage of one or more hydrophilic heated vapors, and wherein the hydrophilic mesoporous membrane permits passage of one or more hydrophilic heated vapors and blocks passage of one or more hydrophobic heated vapors. The method is particularly directed to embodiments where the heated vapors emanate from a pyrolysis process. An apparatus for achieving the above-described method is also described.


Grant
Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 800.50K | Year: 2015

Solar is an increasingly important source of power generation. Word-wide installations of new solar modules will exceed 40GW in 2014 with over 1GW that capacity will be installed in the UK. The cost of modules has decreased sharply over the past two years due to over-supply from manufacturers. The cost reduction is now stimulating demand because the cost of energy from solar is now at grid parity in some important regions of the world. An exciting new type of solar cell based on thin film perovskite light absorbers has been discovered in the UK which has the potential to lower costs still further. The discovery has been made by a team of researchers at Oxford University. The progress they have made with these new devices has been unprecedented and in only two years the Oxford team has achieved conversion efficiencies exceeding 17%. Moreover, the technology has been protected by filing patent applications on the fundamental discoveries. The Supergen Supersolar Hub comprises eight of the UKs leading University groups (including Oxford) engaged in the development of photovoltaic technologies. The Supergen SuperSolar Hub was quick to recognise the importance of the perovskite development and has already funded complementary research programmes in Hub member and Associate member laboratories through its flexible funding. This proposal for Supergen + funding will increase the scope and ambition of the Hubs perovskite research in modelling, synthesis, process optimization and characterization to boost conversion efficiencies still further and help maintain the UKs leadership position. In addition to the proposed research, proposals are made to increase the Hubs involvement with industry and with leading International laboratories to accelerate progress and lay the foundations for timely exploitation.


Patent
Massachusetts Institute of Technology and National Renewable Energy Laboratory | Date: 2016-04-01

Using fundamental electronic structure properties as an indicative of defect tolerance, a broad class of semiconductors containing partially oxidized cations can be identified, as well as several specific instances that can share these properties. These defect tolerant semiconductors can make a high-performance optoelectric device, for example, photovoltaic cells.


Grant
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase II | Award Amount: 749.93K | Year: 2015

With the continued electrification of military systems, lithium-ion (Li ion) batteries are increasingly targeted for electrical energy storage due to exceptional energy and power density. However, Li ion batteries operating in hostile thermal and mechanical environments typical of military aircraft are prone to catastrophic thermally-induced failures. Hazards including loss of power, fire, and explosion are unacceptable for airborne platforms in particular. Consequently, there is great interest in advanced thermal management and thermal fault mitigation strategies to optimize pack performance and enhance safety. This program matures a novel multi-tiered approach coupling high conductance phase change heat removal techniques with active monitoring and control strategies to improve the safety of Li ion battery packs. Phase I leveraged previously developed Li ion battery analytical models and experiments to demonstrate improved thermal performance over other heat spreader technologies. During Phase II we will complete development and conduct extensive lab testing with a full-scale prototype battery pack.bd


Grant
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase II | Award Amount: 749.93K | Year: 2015

Rechargeable lithium ion battery systems can provide power throughout the aircraft, including engine or Auxiliary Power Unit (APU) starting, avionics, emergency, and other systems. Because of their high specific energy/power and potential thermal instability, they can present hazards if improperly designed, tested, handled, or stored. To address the thermal safety issue of Li-ion batteries, EIC Labs, in collaboration with National Renewable Energy Laboratory (NREL), is working on the development of safe, large-format aircraft Li-ion batteries where thermal propagation of an overheated cell to neighboring cells or group of cells is prevented by novel thermal management technologies.


King P.W.,National Renewable Energy Laboratory
Biochimica et Biophysica Acta - Bioenergetics | Year: 2013

The direct conversion of sunlight into biofuels is an intriguing alternative to a continued reliance on fossil fuels. Natural photosynthesis has long been investigated both as a potential solution, and as a model for utilizing solar energy to drive a water-to-fuel cycle. The molecules and organizational structure provide a template to inspire the design of efficient molecular systems for photocatalysis. A clear design strategy is the coordination of molecular interactions that match kinetic rates and energetic levels to control the direction and flow of energy from light harvesting to catalysis. Energy transduction and electron-transfer reactions occur through interfaces formed between complexes of donor-acceptor molecules. Although the structures of several of the key biological complexes have been solved, detailed descriptions of many electron-transfer complexes are lacking, which presents a challenge to designing and engineering biomolecular systems for solar conversion. Alternatively, it is possible to couple the catalytic power of biological enzymes to light harvesting by semiconductor nanomaterials. In these molecules, surface chemistry and structure can be designed using ligands. The passivation effect of the ligand can also dramatically affect the photophysical properties of the semiconductor, and energetics of external charge-transfer. The length, degree of bond saturation (aromaticity), and solvent exposed functional groups of ligands can be manipulated to further tune the interface to control molecular assembly, and complex stability in photocatalytic hybrids. The results of this research show how ligand selection is critical to designing molecular interfaces that promote efficient self-assembly, charge-transfer and photocatalysis. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. © 2013 Elsevier B.V. All rights reserved.


Dillon A.C.,National Renewable Energy Laboratory
Chemical Reviews | Year: 2010

Carbon multiwall nanotubes (MWNTs) and single-wall nanotubes (SWNTs) may be employed to improve upon photoconversion and electrical energy storage technologies. Carbon nanotubes have also been employed in PV devices to improve both exciton generation as well as transport of photoexcited carriers. Every SWNT can be considered to be a unique molecule, with different physical properties, depending on its indices, where the chiral vector magnitude denotes the nanotube circumference. The chiral angle is measured between the roll-up vector and the zigzag axis. Carbon multiwall nanotubes have electronic properties similar to those of graphite and are thus semimetals. Similar to SWNTs, a continuous low-cost production method producing MWNTs that are easily purified is required for MWNTs to be incorporated in emerging technologies. Other forms of nanographitic carbons may also prove promising in the development of next-generation renewable energy devices.


Lany S.,National Renewable Energy Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Many-body GW calculations have emerged as a standard for the prediction of band gaps, band structures, and optical properties for main-group semiconductors and insulators, but it is not well established how predictive the GW method is in general for transition metal (TM) compounds. Surveying the series of 3d oxides within a typical GW approach using the random-phase approximation reveals mixed results, including cases where the calculated band gap is either too small or too large, depending on the oxidation states of the TM (e.g., FeO/Fe2O3, Cu2O/CuO). The problem appears to originate mostly from a too high average d-orbital energy, whereas the splitting between occupied and unoccupied d symmetries seems to be reasonably accurate. It is shown that augmenting the GW self-energy by an attractive (negative) and occupation-independent on-site potential for the TM d orbitals with a single parameter per TM cation can reconcile the band gaps for different oxide stoichiometries and TM oxidation states. In Cu2O, which is considered here in more detail, standard GW based on wave functions from initial density or hybrid functional calculations yields an unphysical prediction with an incorrect ordering of the conduction bands, even when the magnitude of the band gap is in apparent agreement with experiment. The correct band ordering is restored either by applying the d-state potential or by iterating the wave functions to self-consistency, which both have the effect of lowering the Cu-d orbital energy. While it remains to be determined which improvements over standard GW implementations are needed to achieve an accurate ab initio description for a wide range of transition metal compounds, the application of the empirical on-site potential serves to mitigate the problems specifically related to d states in GW calculations. © 2013 American Physical Society.


Beard M.C.,National Renewable Energy Laboratory
Journal of Physical Chemistry Letters | Year: 2011

Multiple exciton generation in quantum dots (QDs) has been intensively studied as a way to enhance solar energy conversion by utilizing the excess energy in the absorbed photons. Among other useful properties, quantum confinement can both increase Coulomb interactions that drive the MEG process and decrease the electron-phonon coupling that cools hot excitons in bulk semiconductors. However, variations in the reported enhanced quantum yields (QYs) have led to disagreements over the role that quantum confinement plays. The enhanced yield of excitons per absorbed photon is deduced from a dynamical signature in the transient absorption or transient photoluminescence and is ascribed to the creation of biexcitons. Extraneous effects such as photocharging are partially responsible for the observed variations. When these extraneous effects are reduced, the MEG efficiency, defined in terms of the number of additional electron-hole pairs produced per additional band gap of photon excitation, is about two times better in PbSe QDs than that in bulk PbSe. Thin films of electronically coupled QDs have shown promise in simple photon-to-electron conversion architectures. If the MEG efficiency can be further enhanced and charge separation and transport can be optimized within QD films, then QD solar cells can lead to third-generation solar energy conversion technologies. © 2011 American Chemical Society.


Gregg B.A.,National Renewable Energy Laboratory
Journal of Physical Chemistry Letters | Year: 2011

The role of entropy in charge separation processes is discussed with respect to the dimensionality of the organic semiconductor. In 1-D materials, the change in entropy, ΔS, plays no role, but at higher dimensions, it leads to a substantial decrease in the Coulomb barrier for charge separation. The effects of ΔS are highest in equilibrium systems but decrease and become time-dependent in illuminated organic photovoltaic (OPV) cells. Higher-dimensional semiconductors have inherent advantages for charge separation, and this may be one reason that C 60 and its derivatives, the only truly three-dimensional organic semiconductors yet known, play such an important role in OPV cells. © 2011 American Chemical Society.

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