Alternative Energy: Progress in Solar Cell Development
In 2012, scientists achieved several important results in the field of alternative energy, particularly for the fabrication of solar cells. Three studies in particular are worthy of being highlighted.
- Researchers from Northwestern University in Illinois reported an improved and more environmentally-friendly version of solar cells based on the use of a dye in the journal Nature in May. They used a system based on nanoporous titanium dioxide (TiO2), the dye N719, and the compound CsSnI2.95F0.05 doped with SnF2, which replaced a liquid electrolyte. This formulation makes the whole system less harmful to the environment. The conversion efficiency was as high as 10.2%, with the cells performing particularly well in the red region of the spectrum.
- Researchers at Berkley University in California developed an architecture method that allows the fabrication of low-cost, high efficiency photovoltaics (PVs) from semiconductors that are normally used in solar cells. The process is called “Screening-Engineered Field-Effect Photovoltaics” (SFPV) and the details published in Nano Letters in July. The system was tested for the fabrication of prototypes, with the results confirming its effectiveness and efficiency.
- Researchers reported the fabrication of the most effective Colloidal Quantum Dots (CQDs) so far in the journal Nature Nanotechnology in July. The research was developed by the University of Toronto in Canada in cooperation with KAUST (Saudi Arabia). The CQDs showed higher efficiency because they had a more compact and regular structure, which was achieved using a hybrid process that uses both large organic and smaller inorganic halogen ligands. These CQDs were successively used to fabricate a solar cell that had 7 % efficiency, the highest ever reported for this kind of material.
All of these results represent important progress for solar cells becoming more common tools for energy production.
Energy Conversion: New Materials for Thermoelectric Effect
Scientists described a new material that can possibly be used for thermoelectric devices in Nature Materials in March. The project was a collaboration between US and Chinese universities.
The material was made of copper (Cu) and selenium (Se), in the form of Cu2-xSe. Its peculiarity is that the selenium provided a solid crystalline structure, but at the same time the copper exhibited a liquid-like behavior. The combination of these two elements led to very interesting properties, that is, relatively high electrical and low thermal conductivities. This is the ideal behavior for a thermoelectric material.
Potentially, this compound could be used to convert temperature differences into electricity, with many technological applications.
2012 in Materials Science
As you can see, 2012 was an interesting year for materials science. From the invisibility cloak and single-atom transistor to advances in solar cells and energy conversion, researchers made a number of significant breakthroughs over the past year. And there will probably be many more in the year to come.
Landy, N., et al. A full-parameter unidirectional metamaterial cloak for microwaves. (2012). Nature Materials, doi:10.1038/nmat3476. Accessed January 5, 2012.
Fuechsle, M., et al. A single-atom transistor. (2012). Nature Nanotechnology. 7, 242-246. Accessed January 5, 2012.
Chung, I., et al. All-solid-state dye-sensitized solar cells with high efficiency. (2012). Nature, 485, 486-489. Accessed January 5, 2012.
Regan, W., et al. Screening-engineered field-effect solar cells. (2012). Nano Letters, 12(8), 4300-4304. Accessed January 5, 2012.
Ip, A.H., et al. Hybrid passivated colloidal quantum dot solids. (2012). Nature Nanotechnology, 7, 577-582. Accessed January 5, 2012.
Liu, H., et al. Copper ion liquid-like thermoelectrics. (2012). Nature Materials, 11, 422-425. Accessed January 5, 2012.
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