EES Blog

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

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

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