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Archive for the ‘Hot Article’ Category

Indium-tin-oxide free polymer solar cells

27 Sep 2012

Currently, polymer and organic solar cells are made using time-consuming and often toxic methods, and use expensive elements in low abundance such as indium-tin-oxide (ITO) and silver electrodes.

Now, scientists in Denmark have developed a solar cell stack that comprises four printed and coated layers using fully automated processing, which is free from ITO and silver.

They have moved the field from rigid, ITO single cells, made using slow vacuum and spin-coating methods, to build flexible modular solar cells, free from ITO, made by full roll-to-roll processing, which is fully scalable.

The performance of the modules is qualitatively similar to ITO based devices – but reducing cost by a factor of >10 and increasing processing speed by a factor of >10.

Read the EES ‘hot article’ hot off the press:

All printed transparent electrodes through an electrical switching mechanism: A convincing alternative to indium-tin-oxide, silver and vacuum
T T Larsen-Olsen et al, Energy Environ. Sci., 2012, DOI: 10.1039/c2ee23244h

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Blue-green algae to covert CO2 into valuable organic chemicals

17 Sep 2012

Researchers in the US have used cyanobacteria (blue-green algae) to covert CO₂ into valuable organic chemicals.

Good conversion rates of 65% were obtained and the authors say that the system could be developed to harvest a range of organic compounds from phototrophs (organisms that carry out photon capture to produce energy, like algae). They add that the tool will facilitate future research on photosynthetic production of biofuels and chemicals and new insights into mechanisms for using cyanobacteria for carbon re-distribution.

Read the ‘HOT’ EES article:

Photo-catalytic conversion of carbon dioxide to organic acids by a recombinant cyanobacterium incapable of glycogen storage
Damian Joseph Carrieri, Troy Paddock, Pinching Maness, Michael Seibert and Jianping Yu
Energy Environ. Sci., 2012, DOI: 10.1039/C2EE23181F

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A method to determine conduction band energy of nanostructured semiconductors

17 Sep 2012

A new method of variable temperature spectroelectrochemistry to measure the conduction band energy of nanoparticle TiO₂ has been developed by scientists in the US. Spectroelectrochemistry combines reaction-oriented electrochemistry with species-focused spectroscopy.

Nanostructured semiconductors such as TiO₂ are important for dye-sensitised solar cells and photocatalysis. Measuring the conduction and valence band energy of semiconductors is one of the most important physical parameters. However, these are currently problematic to measure; there is no reliable method. The new method is quick, makes a minimal number of assumptions and is remarkably versatile. The team says that they expect it could be used with a variety of porous semiconductor materials.

Read the EES ‘HOT’ Communication:

Conduction Band Energy Determination by Variable Temperature Spectroelectrochemistry
Jesse Ondersma and Thomas Hamann
Energy Environ. Sci., 2012, DOI: 10.1039/C2EE22926A

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Cheap and stable fuel cell material

05 Sep 2012

Work by researchers in Singapore on mixed gold, copper and platinum nanoparticles with good electrocatalytic activity and high stability towards the oxygen reduction reaction reported in Energy & Environmental Science has been highlighted in ScienceDaily.

The material represents a cheaper alternative to pure platinum catalysts and have excellent potential for application in fuel cells.

Read the full details on this exciting development today:

Stabilization and compressive strain effect of AuCu core on Pt shell for oxygen reduction reaction
Jinhua Yang, Xiaojun Chen, Xianfeng Yang and Jackie Y. Ying
DOI: 10.1039/C2EE22172A

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Semi-transparent polymer solar cells for power generating window applications

31 Aug 2012

Scientists in the US, Mexico and China have developed semi-transparent organic photovoltaic (OPV) cells with high performance, tuneable transparency and excellent colour perception and rendering properties.

The performance of semi-transparent OPV devices is much lower than their opaque counterparts, and much needs to be done to study and optimise their properties. The team has made semi-transparent OPVs using a low bandgap polymer. By tuning the thickness of the reflective metal electrode, they achieve power conversion efficiencies of 4.25–7.56% and transparency from 2–36%.

They say that their cells have significantly improved performance compared to other semi-transparent OPVs with similar transparencies. The colour rendering indices (CRIs)* of their devices are close to 100, the best values ever reported. (* CRI = quantitative measure of the ability of a light source to reproduce the colours of various objects faithfully in comparison with an ideal or natural light source.)

Polymer solar cells are of interest due to their roll-to-roll fabrication and associated low cost. Semi-transparent OPV devices are a promising candidate for power-generating window applications, as they can be integrated with conventional elements in buildings and vehicles.

Read the ‘HOT’ EES article:

Semi-transparent polymer solar cells with 6% PCE, 25% average visible transmittance and color rendering index close to 100 for power generating window applications
Kung-Shih Chen, Jose Francisco Salinas, Hin-Lap Yip, Jianhui Hou and A Jen
Energy Environ. Sci., 2012, DOI: 10.1039/C2EE22623E

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Doped nanoparticles for smart windows

21 Aug 2012

Table of contents image Chinese scientists have discovered a new method of preparing quasi-spherical VO₂ nanoparticles with uniform size and high crystallinity by doping them with antimony.

These properties are important for application of VO₂ NPs in “smart windows” which can help retain heat at low temperatures and reflect heat at high temperatures.

Read the full details of this exciting work today:

Phase and shape controlled VO₂ nanostructures by antimony doping
Yanfeng Gao, Chuanxiang Cao, Lei Dai, Hongjie Luo, Minoru Kanehira, Yong Ding and Zhong Lin Wang
Energy Environ. Sci., 2012, 5, 8708-8715
DOI: 10.1039/C2EE22290F

Also check out these other recent Energy & Environmental Science articles by Gao et. al. in this exciting research field:

Enhanced chemical stability of VO₂ nanoparticles by the formation of SiO₂/VO₂ core/shell structures and the application to transparent and flexible VO₂-based composite foils with excellent thermochromic properties for solar heat control
Yanfeng Gao, Shaobo Wang, Hongjie Luo, Lei Dai, Chuanxiang Cao, Yiliao Liu, Zhang Chen and Minoru Kanehira
DOI: 10.1039/C2EE02803D

Solution-based fabrication of vanadium dioxide on F:SnO₂ substrates with largely enhanced thermochromism and low-emissivity for energy-saving applications
Zongtao Zhang, Yanfeng Gao, Hongjie Luo, Litao Kang, Zhang Chen, Jing Du, Minoru Kanehira, Yuzhi Zhang and Zhong Lin Wang
DOI: 10.1039/C1EE02092G

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Skeleton and skin strategy for supercapacitors

21 Aug 2012

Scientists in China, Singapore and Australia have made a supercapacitor electrode from a single-walled carbon nanotube (SWCNT) skeleton surrounded by a polyaniline (PANI) skin. This hybrid film was made by in situ electrochemical polymerisation in which a directly grown SWCNT film with continuous reticulate architecture acts as a skeleton and PANI is electrodeposited as a ‘skin’.

The unique reticulate structure of the SWCNT film has an advantage in transporting electrons over a larger area, and the continuous SWCNT/PANI structure avoids the PANI/PANI overlaps seen in other composites, which reduce power density. Previous SWCNT/PANI composite electrodes have been brittle, which hinders their practical application; the films produced here display good mechanical properties, thinness and porosity, making them more applicable in flexible energy storage devices. In addition to this, high energy and power densities were achieved (131 Wh/kg and 62.5 kW/kg, respectively) – this is compared to other CNT/PANI-based supercapacitors (<2.5 kW/kg).

Read this exciting Energy & Environmental Science article today:

A “skeleton/skin” strategy for preparing ultrathin free-standing single-walled carbon nanotube/polyaniline films for high performance supercapacitor electrodes
Zhiqiang Niu, Pingshan Luan, Qi Shao, Haibo Dong, Jinzhu Li, Jun Chen, Duan Zhao, Le Cai, Weiya Zhou, Xiaodong Chen and Sishen Xie
Energy Environ. Sci., 2012, 5, 8726-8733
DOI: 10.1039/C2EE22042C

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Size matters with microbial fuel cells

14 Aug 2012

Scientists working at Oregon State University have made scaled up microbial fuel cells, which use microorganisms to generate electricity from wastewater, that show enhanced performance over those previously studied. The double cloth electrode assembly-based cells were over 10 times larger than those previously reported and showed good performance even after 9 weeks of continuous operation. The group’s results have been highlighted on the ScienceDaily website.

Read the full details of this exciting article today:

Improved performance of CEA microbial fuel cells with increased reactor size
Yanzhen Fan, Sun-Kee Han and Hong Liu
Energy Environ. Sci., 2012, 5, 8273-8280
DOI: 10.1039/C2EE21964F

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Excellent thermoelectrics research from Energy & Environmental Science

08 Aug 2012

We would like to share with you a selection of high impact articles, published in Energy & Environmental Science covering a wide range of thermoelectrics research.

On behalf of Editor-in-Chief Nate Lewis (Caltech), we invite you to submit your best research to Energy & Environmental Science.

With an Impact Factor of 9.61 and ranked #1 in its field, Energy & Environmental Science is the ideal place to publish your research.

Sign up to receive our free table-of-contents e-alert at www.rsc.org/alerts and be among the first to read our newest articles.

Read this high-impact thermoelectrics research today:

Reviews

Perspectives on thermoelectrics: from fundamentals to device applications
M. Zebarjadi, K. Esfarjani, M. S. Dresselhaus, Z. F. Ren and G. Chen
DOI: 10.1039/C1EE02497C

Resonant levels in bulk thermoelectric semiconductors
Joseph P. Heremans, Bartlomiej Wiendlocha and Audrey M. Chamoire
DOI: 10.1039/C1EE02612G

Prospects for polymer-based thermoelectrics: state of the art and theoretical analysis
Theodore O. Poehler and Howard E. Katz
DOI: 10.1039/C2EE22124A

Original research

Low effective mass leading to high thermoelectric performance
Yanzhong Pei, Aaron D. LaLonde, Heng Wang and G. Jeffrey Snyder
DOI: 10.1039/C2EE21536E

High thermoelectric figure of merit in nanostructured p-type PbTe–MTe (M = Ca, Ba)
Kanishka Biswas, Jiaqing He, Guoyu Wang, Shih-Han Lo, Ctirad Uher, Vinayak P. Dravid and Mercouri G. Kanatzidis
DOI: 10.1039/C1EE02297K

Flexible carbon nanotube papers with improved thermoelectric properties
Weiyun Zhao, Shufen Fan, Ni Xiao, Dayong Liu, Yee Yan Tay, Cui Yu, Daohao Sim, Huey Hoon Hng, Qichun Zhang, Freddy Boey, Jan Ma, Xinbing Zhao, Hua Zhang and Qingyu Yan
DOI: 10.1039/C1EE01931G

Enhancement of thermoelectric figure-of-merit by resonant states of aluminium doping in lead selenide
Qinyong Zhang, Hui Wang, Weishu Liu, Hengzhi Wang, Bo Yu, Qian Zhang, Zhiting Tian, George Ni, Sangyeop Lee, Keivan Esfarjani, Gang Chen and Zhifeng Ren
DOI: 10.1039/C1EE02465E

High thermoelectric figure of merit zT>1 in Ba heavily doped BiCuSeO oxyselenides
Li-Dong Zhao, Jing Li, Jiehe Sui, Yanling Pei, Celine Barreteau, David Berardan, Nita Dragoe, Wei Cai and Jiaqing He
DOI: 10.1039/C2EE22622G

Combining alloy scattering of phonons and resonant electronic levels to reach a high thermoelectric figure of merit in PbTeSe and PbTeS alloys
Christopher M. Jaworski, Bartlomiej Wiendlocha, Vladimir Jovovic and Joseph P. Heremans
DOI: 10.1039/C1EE01895G

High thermoelectric figure of merit in heavy hole dominated PbTe
Yanzhong Pei, Aaron LaLonde, Shiho Iwanaga and G. Jeffrey Snyder
DOI: 10.1039/C0EE00456A

A novel high-performance photovoltaic–thermoelectric hybrid device
Ning Wang, Li Han, Hongcai He, Nam-Hee Park and Kunihito Koumoto
DOI: 10.1039/C1EE01646F

Sb₂Te₃ and Bi₂Te₃ based thermopower wave sources
Sumeet Walia, Rodney Weber, Sharath Sriram, Madhu Bhaskaran, Kay Latham, Serge Zhuiykov and Kourosh Kalantar-zadeh
DOI: 10.1039/C1EE01370J

Recrystallization induced in situ nanostructures in bulk bismuth antimony tellurides: a simple top down route and improved thermoelectric properties
Jun-Jie Shen, Tie-Jun Zhu, Xin-Bing Zhao, Sheng-Nan Zhang, Sheng-Hui Yang and Zhen-Zhong Yin
DOI: 10.1039/C0EE00012D

You can find even more great thermoelectric research in our Energy & Environmental Science thermoelectrics web collection.

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New research on capacitive desalination

06 Aug 2012

Desalination is currently a very topical area of research; with the world’s ever increasing population and demand for fresh drinking water. As a result, research in this area is moving fast, with new technologies being developed all the time.

EES has just published papers from two separate groups on the latest developments in capacitive deonization/desalination. Capacitive desalination (CD) is a promising new desalination technique, relative to reverse osmosis (RO), as it can operate at low (sub-osmotic) pressures and has the potential to use less energy when desalinating brackish water (from estuaries and coastal marsland).

The first paper demonstrates an alternative architecture to traditional CD cells, where the feed flows directly through the electrodes along the direction of the primary electric field (flow-through electrode (FTE) capacitive desalination). This novel set-up has resulted in a significant reduction in desalination time and improved salt concentration reductions; with a mean sorption rate of nearly 1 mg NaCl per g aerogel per min, that’s up to 10 times higher than that demonstrated by the typical CD cell:

Capacitive desalination with flow-through electrodes
Matthew E. Suss , Theodore F. Baumann , William L. Bourcier , Christopher M. Spadaccini , Klint A. Rose , Juan G. Santiago and Michael Stadermann
Energy Environ. Sci., 2012, DOI: 10.1039/C2EE21498A

The second paper discusses membrane capacitive deionization (MCDI), which is based on applying a cell voltage between two oppositely placed porous electrodes, with a spacer channel that transports the water to be desalinated. Current MCDI devices operate at a constant cell voltage, resulting in an effluent stream of desalinated water of which the salt concentration varies with time. In this paper, van der Wal and colleagues propose a different operational mode for MCDI, whereby desalination is driven by a constant electrical current, which leads to a constant salt concentration in the desalinated stream over long periods of time. This is shown to significantly reduce energy consumption, which would be essential for the economic viability of membrane-based desalination techniques:

Energy consumption and constant current operation in membrane capacitive deionization
R. Zhao , P. M. Biesheuvel and A. van der Wal
Energy Environ. Sci., 2012, DOI: 10.1039/C2EE21737F

You can read more about desalination in the recent Chemistry World article: Keeping the tap on and other related articles.

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EES Blog

Archive for the ‘Hot Article’ Category

Indium-tin-oxide free polymer solar cells

Blue-green algae to covert CO2 into valuable organic chemicals

A method to determine conduction band energy of nanostructured semiconductors

Cheap and stable fuel cell material

Semi-transparent polymer solar cells for power generating window applications

Doped nanoparticles for smart windows

Skeleton and skin strategy for supercapacitors

Size matters with microbial fuel cells

Excellent thermoelectrics research from Energy & Environmental Science

New research on capacitive desalination

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