Water + air + electricity = hydrogen peroxide:…

Water + air + electricity = hydrogen peroxide: Rice University breakthrough produces valuable chemical on demand at point of use

A reactor developed by Haotian Wang and his colleagues at Rice’s Brown School of Engineering requires only air, water and electricity to make the valuable chemical in the desired concentration and high purity.

Their electrosynthesis process, detailed in Science, uses an oxidized carbon nanoparticle-based catalyst and could enable point-of-use production of pure hydrogen peroxide solutions, eliminating the need to transport the concentrated chemical, which is hazardous.

By using a solid electrolyte instead of traditional liquid electrolyte, it also eliminates the need for product separation or purification used in current processes, so no contaminating ions will be involved.

“If we have electricity from a solar panel, we can literally get hydrogen peroxide from just sunlight, air and water,” said Wang. “We don’t need to involve organics or fossil fuel consumption. Hydrogen peroxide synthesis by traditional, huge chemical engineering plants generates organic wastes, consumes fossil fuels and emits carbon dioxide. What we’re doing is green synthesis.”

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Materials that can revolutionize how light i…

Materials that can revolutionize how light is harnessed for solar energy

Researchers develop new design rule for generating excitons will help advance next-generation devices

Researchers at Columbia University have developed a way to harness more power from singlet fission to increase the efficiency of solar cells, providing a tool to help push forward the development of next-generation devices.

In a study published this month in Nature Chemistry, the team details the design of organic molecules that are capable of generating two excitons per photon of light, a process called singlet fission. The excitons are produced rapidly and can live for much longer than those generated from their inorganic counterparts, which leads to an amplification of electricity generated per photon that is absorbed by a solar cell.

“We have developed a new design rule for singlet fission materials,” said Luis Campos, an associate professor of chemistry and one of three principal investigators on the study. “This has led us to develop the most efficient and technologically useful intramolecular singlet fission materials to date. These improvements will open the door for more efficient solar cells.”

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Improving Solar Cell Efficiency With Nanowir…

Improving Solar Cell Efficiency With Nanowire Arrays

Transparent electrodes are a critical component of solar cells and electronic displays. To collect electricity in a solar cell or inject electricity for a display, you need a conductive contact, like a metal, but you also need to be able to let light in (for solar cells) or out (for displays).

Metal is opaque, so the current techniques use metal oxides, most often indium tin oxide — a near-critical rare earth metal — as the conductive contact. Because supplies of this rare earth metal are limited, Lawrence Livermore National Laboratory (LLNL) researchers have turned to ordered metal nanowire meshes that provide high transmissivity (due to the small diameters of the nanowires), high electrical connectivity (due to the many contact points in the mesh) and use more common elements. The research appears in the journal Soft Matter.

The nanowire arrays also have applications for optical metamaterials — composite materials usually made of metals and dielectrics — that have unique optical properties not found in nature. For example, all naturally occurring materials have a positive index of refraction. But metamaterials can be designed to have a negative index of refraction, which means that light passing through this material would go in the opposite direction from what one would normally see, and can create structures like cloaking devices and perfect lenses.

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The blade of a wind turbine being transporte…

The blade of a wind turbine being transported through city streets. 

Scientists discover material that can make s…

Scientists discover material that can make solar cells more efficient

Researchers at Siberian Federal University, together with colleagues from the Royal Institute of Technology (Stockholm, Sweden), discovered new properties of material based on palladium, which can increase the performance of solar cells.

Palladium diselenide is a promising material whose properties have not yet been fully studied. For example, it was reported that its two-dimensional form can be effective in photocatalysis—the process of splitting water into hydrogen and oxygen when exposed to sunlight, which can be used to produce ecological fuel. Researchers have recently learned how to synthesize single- and double-layered versions of the PdSe2 composition, but the strengths and weaknesses of these materials remained unknown until recently. The researchers used high-precision calculation methods for the first time and managed to study the electronic and optical properties of single- and two-layer material based on palladium diselenide in detail, which, as it turned out, can absorb solar energy more efficiently than silicon-based material used in solar batteries.

“The material demonstrates higher conversion rates of solar energy into electrical energy due to a wider spectrum of energy absorption compared to silicon-based elements used today as semiconductors, and therefore can significantly increase the efficiency of solar cells… Palladium diselenide (PdSe2) can be used as an independent material for solar cell elements in the construction of spacecraft and artificial Earth satellites, since the material efficiency in most cases justifies the costs in the space industry,” says one of the researchers from Siberian Federal University, Artem Kuklin.

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Treating solar cell materials reveals format…

Treating solar cell materials reveals formation of unexpected microstructures

Recent advances in solar cell technology use polycrystalline perovskite films as the active layer, with an increase to efficiency of as much as 24.2%. Hybrid organic-inorganic perovskites are especially successful, and they have been used in optoelectronic devices including solar cells, photodetectors, light-emitting diodes and lasers.

But the surface of hybrid perovskites is prone to surface defects, or surface traps, where charge carriers are trapped in the semiconducting material. To solve this problem and reduce the number of traps, the crystal surface must be passivated.

Before use, perovskites can be treated with chemical solutions, vapors and atmospheric gases to remove defects that make the material less effective. Benzylamine is one particularly successful molecule for this purpose. A detailed understanding of the physical and chemical mechanisms by which these treatments work is key to increasing the collection of charge carriers in solar cells.

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New Kind of Solar Cell Opens the Door for Su…

New Kind of Solar Cell Opens the Door for Surpassing Efficiency Limit 

In any conventional silicon-based solar cell, there is an absolute limit on overall efficiency, based partly on the fact that each photon of light can only knock loose a single electron, even if that photon carried twice the energy needed to do so. But now, researchers have demonstrated a method for getting high-energy photons striking silicon to kick out two electrons instead of one, opening the door for a new kind of solar cell with greater efficiency than was thought possible.

While conventional silicon cells have an absolute theoretical maximum efficiency of about 29.1 percent conversion of solar energy, the new approach, developed over the last several years by researchers at MIT and elsewhere, could bust through that limit, potentially adding several percentage points to that maximum output. The results are described today in the journal Nature, in a paper by graduate student Markus Einzinger, professor of chemistry Moungi Bawendi, professor of electrical engineering and computer science Marc Baldo, and eight others at MIT and at Princeton University.

The basic concept behind this new technology has been known for decades, and the first demonstration that the principle could work was carried out by some members of this team six years ago. But actually translating the method into a full, operational silicon solar cell took years of hard work, Baldo says.

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Solar steam generators could be made with wo…

Solar steam generators could be made with wood, fabric or sponges

As the global population grows, fresh water supplies are more precious than ever. While scientists and engineers know how to purify water, making those methods sustainable and energy efficient is another question.

One promising approach is solar-driven distillation, or solar steam generation, which can help us get fresh water from wastewater or seawater. Researchers have used this method to successfully distill small batches of purified water, but they are still searching for a way to do this on a large scale.

Researchers at the University of Chicago’s Pritzker School of Molecular Engineering and UChicago-affiliated Argonne National Laboratory were part of a team that developed a pioneering new method of solar steam generation that could help bring this technology into the real world. The materials can be grown on top of wood, fabric or sponges in an easy, one-step process, and show promise for large-scale manufacturing.

“Solar steam generation techniques are still mostly focused on lab use now,” said Zijing Xia, a graduate student at Pritzker Molecular Engineering and lead author of the research. “We want to find an easy way to fabricate solar steam generators at relatively low cost.”

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New findings could lead to cheaper solar cel…

New findings could lead to cheaper solar cells

At the atomic scale materials can show a rich palette of dynamic behaviour, which directly affects the physical properties of these materials. For many years, it has been a dream to describe these dynamics in complex materials at various temperatures using computer simulations. Physicists of the University of Vienna have developed an on-the-fly machine-learning method that enables such calculations through direct integration into the quantum mechanics based Vienna Ab-initio Simulation Package (VASP). The versatility of the self-learning method is demonstrated by new findings, published in the journal Physical Review Letters, on the phase transitions of hybrid perovskites. These perovskites are of great scientific interest due to their potential in solar energy harvesting and other applications.

At room temperature, all materials are constantly moving at the atomic scale. Even solid rock consists of atoms that swing around. The physical properties of materials are directly linked to the arrangement of atoms in the, so called, crystal lattice. Depending on the temperature or pressure this arrangement can change thereby affecting the materials properties. One can think of diamond, which is transparent and hard because of the periodic arrangement of carbon atoms in the diamond crystal. The same atoms, arranged differently, results in black, brittle graphite. It was already possible to accurately calculate the coordinates of the atoms in simple materials at different temperatures with quantum mechanical molecular dynamics (MD) simulations. However, such calculations are computationally expensive and restrict practical applications to a couple of hundreds of atoms and limited simulation time.

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The Costasiella kuroshimae Sea Slug. This Sea…

The
Costasiella kuroshimae Sea Slug.

This Sea Slug lives off the coast of
Japan, Indonesia and The Philippines and grazes on algae. It forms a
unique relationship with algae as it consumes the chloroplasts of its
food and then uses the chloroplasts within its own system.
photosynthesising and producing its own solar powered energy made from
the sun – just like plants. ⠀

Images via Jim Lynn and Lynn Wu. ⠀

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