Los Alamos National Laboratory Studies Perovskites for Efficient Optoelectronics: Video


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In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are gaining an extra degree of freedom in designing and fabricating efficient optoelectronic devices based on 2D layered hybrid perovskites. Industrial applications could include low cost solar cells, LEDs, laser diodes, detectors, and other nano-optoelectronic devices.

Los Alamos Lab lanl-logo-footerThe 2D, near-single-crystalline “Ruddlesden-Popper” thin films have an out-of-plane orientation so that uninhibited charge transport occurs through the perovskite layers in planar devices. The new research finds the existence of “layer-edge-states” at the edges of the perovskite layers which are key to both high efficiency of solar cells (greater than 12 percent) and high fluorescence efficiency (a few tens of percent) for LEDs. The spontaneous conversion of excitons (bound electron-hole pairs) to free carriers via these layer-edge states appears to be the key to the improvement of the photovoltaic and light-emitting thin film layered materials.

Watch the Video

See the news release here:
http://www.lanl.gov/discover/news-rel…

And the research paper in Science:
http://science.sciencemag.org/content…

What is up with the U.S. ‘Solar Industry’? Is There and Impending US Solar Energy Crash?


Solar Crash I solar-and-wind-energy

After nice stretch of sunny weather, the last few months have clouded over for big solar. Declining prices for photovoltaic cells are hurting panel manufacturers and stressing solar installation businesses.

This situation was in sharp relief this week in Tesla’s (TSLA Tesla Motors Inc TSLA 307.19 -0.38%) earnings, as its solar installation business, SolarCity, disclosed a big slowdown in builds. SolarCity commands 41 percent of the residential solar installation market, according to GTM. In its latest earnings, the firm revealed that it had installed 150 MW of panels in the first quarter, down nearly 39 percent y/y.

“Rather than prioritizing the growth of MW of solar deployed at any cost, we are selectively deploying projects that have higher margin and generate cash up front. Consequently, solar energy generation deployments in Q1 2017 declined year-over-year, but had better financial results,” said the earnings release.

The Curious Logic of the Solar Market

Industry body Solar Energy Industries Association (SEIA) reports that installations for the past year actually went up. In 2016, the U.S. saw 14.8GW solar capacity installed with a new installation taking place every 84 seconds.

There are companies that are doing well. First Solar (FSLR First Solar In FSLR 35.15 +1.77%) just reported strong earnings while Vivint Solar (VSLR Vivint Solar Inc VSLR 3.00+1.70%) announced is expansion into Rhode Island and is expected to announce financial results next week. However, the list of struggling companies in the sector is longer.

SunPower Corp. (SPWR) reported its sixth consecutive quarter of losses and laid off 25 percent of its workforce. Verengo Solar filed for bankruptcy last year, while Sungevity and Suninva did the same earlier this year.

But if solar energy is seeing such high demand, why are the companies feeling the heat?

The Price Is Not Right

The cost of the production and installation of solar panels has dropped dramatically and that is driving demand. According to SEIA, the cost to install solar capacity dropped 29 percent in the final quarter of 2016, compared to the same period last year. Over the past 10 years, installation costs have come down by nearly 60 percent.

There is more than one reason for price suppression in the solar industry.

“Driving the cost reductions were lower module and inverter prices, increased competition, lower installer and developer overheads, improved labor productivity, and optimized system configurations,” a National Renewable Energy Laboratory report states.

At home, the government tried to promote solar energy to consumers by making it affordable. One such initiative was the Solar Investment Tax Credit for residential and business solar installations, adopted in 2006 and extended in 2015.

In the international arena, U.S. solar companies blame declining panel prices on foreign imports, especially from countries like China, Mexico and Canada. Suniva recently implored President Trump for protectionist policies for the sector.

However, as the big ones struggled, someone made hay as the sun shone. According to GTM research’s U.S. Residential Solar Update 2017, many of the larger firms struggled to do well while smaller, local companies thrived.

More Insights: Investopedia http://www.investopedia.com/news/solar-industry-slowdown-catches-solarcity/#ixzz4gWsv7IYa

Perovskite Nanocrystals: Bright – Cheap – Stable: Discovery Illuminates Path to Highly Efficient Perovskite based Quantum Dots Photovoltaics


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Digital picture of colloidal solution in toluene taken under UV-light (λ = 365 nm) and crystal structure of Formamidinium lead-halide perovskite. (Image: Friedrich-Alexander-Universität Erlangen-Nürnberg)

The team reports facile and rapid room temperature synthesis of cubic and platelet-like colloidal nanocrystals (NCs) of Formamidinium Lead Halide Perovskite FAPbX3 (X=Cl, Br, I, or mixed Cl/Br and Br/I) by ligand-assisted re-precipitation method (LARP).
The obtained NCs are 15-25 nm in size and exhibit a remarkably high photoluminescence quantum yield of up to 85% as well as colloidal and chemical stability.
The cubic and platelet-like NCs with their emission in the range of 415-740 nm, full width at half maximum of 20-44 nm and radiative lifetimes of 5-166 ns, allow precise band gap tuning by halide composition as well as by tailoring their dimensions.
Notably, for the first time they have demonstrate thermodynamically stable FAPbI3 NCs in the black cubic α-phase without transition to the yellow hexagonal δ-phase even after 150 days of storage. This is in strong contrast to polycrystalline films and single crystals which convert within hours.
This fact paves the way to highly efficient perovskite based quantum dots photovoltaics, which is underpinned by demonstrating FAPbI3 NCs based photodetector.
To highlight the potential of FAPbX3 NCs as a promising candidate for optoelectronic and luminescent applications, the scientists modified the surface with polyhedral oligomeric silsesquioxane. This modification protects the brightly luminescent FAPbX3 NCs from decomposition even after storage in water for more than 2 months.
Source: Friedrich-Alexander-Universität Erlangen-Nürnberg

 

Improving Perovskites to Surpass Silicon Solar Cell Performance: Answers from ANSER


Perovskites Water id46564The perovskite device is made of different layers, each of which has a specific function. Together, the titanium dioxide and PC61BM layers protect the perovskite from heat and water. (Image: Rebecca Palmer, ANSER EFRC)

 

Harvesting sunlight and using it to power our homes and devices is a reality today. Generally, most commercial solar cells are made of silicon. However, as highlighted previously, a type of material called perovskite halides are a potential competitor of silicon. Unfortunately, most perovskite halides are sensitive to moisture and high temperatures such that exposure to either will quickly degrade these materials — rendering them useless. Researchers at the Argonne-Northwestern Solar Energy Research Center (ANSER) have developed a way to protect perovskites from water and stabilize them against heat. By carefully growing an ultrathin layer of metal oxide on a carbon coating, the researchers made a perovskite device that worked even after dousing the device with a stream of water (Nano Letters, “Liquid Water- and Heat-Resistant Hybrid Perovskite Photovoltaics via an Inverted ALD Oxide Electron Extraction Layer Design”).

Solar cells are made up of layers, each with a specific duty. The perovskite layer absorbs sunlight, which can excite an electron. The electron could go right back to where it started, unless it can be extracted out of the absorbing layer quickly. For this device, the researchers placed a layer of PC61BM, a carbon-based material, on top of the perovskite, which has two roles. First, PC61BM is good at extracting electrons once they are excited by sunlight. Second, the PC61BM layer protects the perovskite from water vapor, which is one of the reactants used for forming the final protective coating — titanium dioxide.
The titanium dioxide layer was grown using atomic layer deposition (ALD), a method that deposits alternating layers of titanium and oxygen atoms. The researchers demonstrated that depositing the titanium dioxide by ALD creates a barrier with no pinholes, effectively blocking moisture from entering the film. Only about 20 nanometers of titanium dioxide on the PC61BM were needed to protect the perovskite. This layer is around 1,000 times thinner than the thickness of a human hair.
On top of the titanium dioxide, aluminum electrodes were deposited and protected by a thin layer of gold. On the opposite side of the perovskite, the team placed a nickel oxide layer that is good at extracting the positively charged holes left by the electrons. Glass, coated with a conductive film, is used as a support that allows light to pass through and a circuit to be formed.
The device held up to pure water and a temperature of 100 °C (around 200 °F) thanks to the titanium dioxide layer. In Soo Kim, a postdoctoral fellow and lead researcher, explained that he was excited about this result. “The key challenge to commercialization of any halide perovskite-based devices is the environmental stability.”
Many people have been studying perovskite halides, but the stability under real-world environmental situations has been largely overlooked. Kim’s work is one of the first examples of protecting perovskite from liquid water with an ultrathin metal oxide layer. Alex Martinson, who directed the work, said, “It is surprising when something simple works so well.”
Martinson explained that perovskite solar cells have a lot of promise because they have the potential to be cheaper than the current commercial devices, such as silicon. The silicon manufacturing process is energy intensive, and silicon materials are required to be highly pure. In contrast, there are many pathways to make perovskites, and the performance of perovskite devices are less sensitive to impurities. Scientists at ANSER are excited to continue to explore what perovskites can do. Enabling these devices to withstand water and heat is a big step towards being able to buy a perovskite device at a local hardware store.
Source: By Rebecca Palmer, Energy Frontier Research Centers

Read more: Teaching perovskites to swim

Experts Outline Pathway for Generating Up to Ten (10) Terawatts of Power from Sunlight by 2030: NREL – GA SERI


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The annual potential of solar energy far exceeds the world’s energy consumption, but the goal of using the sun to provide a significant fraction of global electricity demand is far from being realized.

Scientists from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), their counterparts from similar institutes in Japan and Germany, along with researchers at universities and industry, assessed the recent trajectory of photovoltaics and outlined a potential worldwide pathway to produce a significant portion of the world’s electricity from solar power in the new Science paper, Terawatt-Scale Photovoltaics: Trajectories and Challenges.NREL I download

Fifty-seven experts met in Germany in March 2016 for a gathering of the Global Alliance of Solar Energy Research Institutes (GA-SERI), where they discussed what policy initiatives and technology advances are needed to support significant expansion of solar power over the next couple of decades.

“When we came together, there was a consensus that the global PV industry is on a clear trajectory to reach the multi-terawatt scale over the next decade,” said lead author Nancy Haegel, director of NREL’s Materials Science Center. “However, reaching the full potential for PV technology in the global energy economy will require continued advances in science and technology. Bringing the global research community together to solve challenges related to realizing this goal is a key step in that direction.”

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Photovoltaics (PV) generated about 1 percent of the total electricity produced globally in 2015 but also represented about 20 percent of new installation. The International Solar Alliance has set a target of having at least 3 terawatts – or 3,000 gigawatts (GW) – of additional solar power capacity by 2030, up from the current installed capacity of 71 GW. But even the most optimistic projections have under-represented the actual deployment of PV over the last decade, and the GA-SERI paper discusses a realistic trajectory to install 5-10 terawatts of PV capacity by 2030.

Reaching that figure should be achievable through continued technology improvements and cost decreases, as well as the continuation of incentive programs to defray upfront costs of PV systems, according to the Science paper, which in addition to Haegel was co-authored by David Feldman, Robert Margolis, William Tumas, Gregory Wilson, Michael Woodhouse, and Sarah Kurtz of NREL.

GA-SERI’s experts predict 5-10 terawatts of PV capacity could be in place by 2030 if these challenges can be overcome:

  • A continued reduction in the cost of PV while also improving the performance of solar modules
  • A drop in the cost of and time required to expand manufacturing and installation capacity
  • A move to more flexible grids that can handle high levels of PV through increased load shifting, energy storage, or transmission
  • An increase in demand for electricity by using more for transportation and heating or cooling
  • Continued progress in storage for energy generated by solar power.

The Fraunhofer Institute for Solar Energy (Germany), the National Institute of Advanced Industrial Science and Technology (Japan), and the National Renewable Energy Laboratory (United States) are the member institutes of GA-SERI, which was founded in 2012.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

UT Austin’s and Goodenough’s New ‘Solid Electrolyte Battery’ ~ Stumps Researchers – Video


  • Lithium-Ion battery inventor 94 year old John Goodenough has stumped researchers evaluating his recent discovery and resulting claims.
  • Greater Energy Density
  • Faster/ Rapid Re-Charging
  • SAFE! Non-Exploding
  • Low Cost Materials
  • Low Cost to Manufacture

Is the discovery the answer to much needed Energy Storage for Renewable Energies? The Electric Vehicle (EVs) ?

Watch the Video and tell us what you think? Leave us your Comments!

NREL & Colorado School of Mines Researchers Capture Excess Photon Energy to Produce Solar Fuels



Photo shows a lead sulfide quantum dot solar cell. A lead sulfide quantum dot solar cell developed by researchers at NREL. Photo by Dennis Schroeder.




Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have developed a proof-of-principle photoelectrochemical cell capable of capturing excess photon energy normally lost to generating heat.


Using quantum dots (QD) and a process called Multiple Exciton Generation (MEG), the NREL researchers
were able to push the peak external quantum efficiency for hydrogen generation to 114 percent.


The advancement could significantly boost the production of hydrogen from sunlight by using the cell to split water at a higher efficiency and lower cost than current photoelectrochemical approaches.

Details of the research are outlined in the Nature Energy paper Multiple exciton generation for photoelectrochemical hydrogen evolution reactions with quantum yields exceeding 100%, co-authored by Matthew Beard, Yong Yan, Ryan Crisp, Jing Gu, Boris Chernomordik, Gregory Pach, Ashley Marshall, and John Turner.

All are from NREL; Crisp also is affiliated with the Colorado School of Mines, and Pach and Marshall are affiliated with the University of Colorado, Boulder.




Beard and other NREL scientists in 2011 published a paper in Science that showed for the first time how MEG allowed a solar cell to exceed 100 percent quantum efficiency by producing more electrons in the electrical current than the amount of photons entering the solar cell.




“The major difference here is that we captured that MEG enhancement in a chemical bond rather than just in the electrical current,” Beard said.

“We demonstrated that the same process that produces extra current in a solar cell can also be applied to produce extra chemical reactions or stored energy in chemical bonds.”

The maximum theoretical efficiency of a solar cell is limited by how much photon energy can be converted into usable electrical energy, with photon energy in excess of the semiconductor absorption bandedge lost to heat.

The MEG process takes advantages of the additional photon energy to generate more electrons and thus additional chemical or electrical potential, rather than generating heat. QDs, which are spherical semiconductor nanocrystals (2-10 nm in diameter), enhance the MEG process.




In current report, the multiple electrons, or charge carriers, that are generated through the MEG process within the QDs are captured and stored within the chemical bonds of a H2 molecule.

NREL researchers devised a cell based upon a lead sulfide (PbS) QD photoanode. The photoanode involves a layer of PbS quantum dots deposited on top of a titanium dioxide/fluorine-doped tin oxide dielectric stack.

The chemical reaction driven by the extra electrons demonstrated a new direction in exploring high-efficiency approaches for solar fuels.

Funds for the research came from the Department of Energy’s Office of Science.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Renewable Energy Needed to Drive Uptake of Electric Vehicles ~ Queensland University


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Plugging into renewable energy sources outweighs the cost and short driving ranges for consumers intending to buy electric vehicles, according to a new study.

Queensland University of Technology Postdoctoral Research Fellow Dr Kenan Degirmenci, from QUT Business School, said environmental performance – or being green – was more important than price or range confidence for electric vehicle consumers.

“High purchase costs and short driving ranges have been considered to be the main factors which impede people’s decision to buy electric vehicles,” he said.

“Since electricity needs to be produced from renewable energy sources for electric vehicles to be a true green alternative, the environmental performance has also been presumed to be a factor.”unplugged-performance-tesla-model-s-02-668x409

In a newly published study titled Consumer purchase intentions for electric vehicles: Is green more important than price and range? Dr Degirmenci found environmental performance was in fact an even stronger predictor of purchase intention over price and range confidence.

The study involved interviews with 40 consumers and a survey with 167 people who participated in test drives with plug-in battery electric vehicles in Germany.

“We found the majority of participants placed great emphasis on the need for electricity for electric vehicles to be produced from renewable energy sources in order for them to be a true alternative,” he said.

Dr Degirmenci said when considering greenhouse gas emissions it was important to acknowledge the difference between on-road emissions only taking into account the fuel used, and well-to-wheel emissions including all emissions related to fuel production, processing, distribution and use.

“For example, a petrol-driven vehicle produces 119g CO2-e/km, of which most are on-road emissions. In comparison, an electric vehicle produces zero on-road emissions,” he said.

“However, if electricity is generated from coal to charge an electric vehicle it produces 139g CO2-e/km well-to-wheel emissions, compared with only 9g CO2-e/km well-to-wheel emissions with electricity from renewable energy sources.”

Dr Degirmenci said the results of the study were relevant to Australia because the transport sector accounted for 16 per cent of the country’s greenhouse gas emissions and 85 per cent of these were generated by road transport.

“In this regard, a transition from conventional combustion vehicles to electric vehicles has the potential to reduce Australia’s greenhouse gas emissions substantially, if that electricity is produced from renewable energy sources,” Dr Degirmenci said.

ONE (1) Solar Power Plant in the Chilean desert (775,000 panels) = Energy for 1 (ONE) MILLION People ~ Video


World Future Energy large_ThCDvzfTqZJX8Ck7wK5fPkvkp_33ZO7OXoBxpOrqP1UThe way energy is produced, distributed and consumed around the world is undergoing fundamental change of almost unprecedented proportions. This is commonly referred to as the “energy transition”. (watch the video)

 

 

The Global Energy Architecture Performance Index 2017 (EAPI), tackles elements of this transition in its fifth annual edition, as do the global Regulatory Indicators for Sustainable Energy (RISE) released by the World Bank a month earlier. Of specific interest to this essay are the underlying issues of governance and regulation and their relationship to progress towards sustainable and secure energy systems. In UN development terms, this focus helps us consider the links between Sustainable Development Goal (SDG) 7, which addresses energy, and SDG 16, which is about peace and justice.

Read More: The way the world produces and consumes energy is changing. How can we meet the needs of the future?

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Fern-Inspired Energy Storage Could Further Solar Power


fernThe breakthrough electrode prototype (right) can be combined with a solar cell (left) for on-chip energy harvesting and storage. Credit: RMIT University

A new type of electrode may help researchers finally solve one of the challenges preventing solar power from becoming a total energy solution.

RMIT University researchers believe a new graphene-based prototype— which is inspired by the structure of fern leaves— could boost the capacity of existing integrable storage by 3,000 percent and open a new path to the development of flexible thin film all-in-one solar capture and storage.

This advancement may lead to self-powering smart phones, laptops, cars and buildings.

The electrode is designed to work with supercapacitors, which can charge and discharge power significantly faster than conventional batteries. Supercapacitors have been combined with solar in the past, but their wider use as a storage solution is restricted because of their limited capacity.

The fractal design reflected the self-repeating shape of the veins of the western swordfern—Polystichum munitum—native to western North America.

RMIT’s Professor Min Gu explained how the prototype is based on the fern leaves.

RMIT images“The leaves of the western swordfern are densely crammed with veins, making them extremely efficient for storing energy and transporting water around the plant,” Gu, the leader of the Laboratory of Artificial Intelligence Nanophotonics and associate deputy vice-chancellor for Research Innovation and Entrepreneurship at RMIT, said in a statement.

Gu explained that the electrode is based on self-replicating fractal shapes and the researchers used the naturally-efficient design to improve solar energy storage at a nano level.

“The immediate application is combining this electrode with supercapacitors, as our experiments have shown our prototype can radically increase their storage capacity—30 times more than current capacity limits,” Gu said. “Capacity-boosted supercapacitors would offer both long-term reliability and quick-burst energy release for when someone wants to use solar energy on a cloudy day for example—making them ideal alternatives for solar power storage.”

Solar energy storage is an emerging technology that can promote the solar energy as the primary source of electricity. Recent developments of laser scribed graphene electrodes exhibiting a high electrical conductivity have enabled a green technology platform for supercapacitor-based energy storage, resulting in cost-effective, environment-friendly features and consequent readiness for on-chip integration.

According to the study, the new conceptual design removes the limit of the conventional planar supercapacitors by significantly increasing the ratio of active surface area to volume of the new electrodes and reducing the electrolyte ionic path.

The researchers combined the fractal-enabled laser-reduced graphene electrodes with supercapacitors to hold the stored charge for longer with minimal leakage.

Ph.D. researcher Litty Thekkekara explained that there are many applications for the prototype.

 “Flexible thin film solar could be used almost anywhere you can imagine, from building windows to car panels, smart phones to smart watches. We would no longer need batteries to charge our phones or charging stations for our hybrid cars. With this flexible electrode prototype we’ve solved the storage part of the challenge, as well as shown how they can work with solar cells without affecting performance,” she said.

“Now the focus needs to be on flexible solar energy, so we can work towards achieving our vision of fully solar-reliant, self-powering electronics.”

The study was published in Scientific Reports.