Paints that power home

Quantum dots convert sunlight into electricity

By Shruti Chowdhari
Published: Wednesday 15 February 2012

imageYOU could soon get over with the cumbersome task of installing solar panels on roof-top. All you would need to do is paint your home.

Scientists from University of Notre Dame in the US have developed a paint that can convert light energy into electrical energy.

The solar paint consists of quantum dots, which are power-producing nanoparticles. In this case, low-cost titanium dioxide (TiO2) is covered either with cadmium sulfide (CdS) or cadmium selenide (CdSe). It is CdS and CdSe which absorb light and activate the TiO2 to conduct electricity. The quantum dots are suspended in a water-alcohol mixture and made into a spreadable compound. It can then be spread onto any conductive surface. Quantum dots being exceptionally small in size, when aggregated together, provide huge cross-section area to capture nearly all of the incident solar light. “The effort to prepare solar paint offers the advantages of simple design and economically viable next generation solar cells.

Improvements are necessary to develop strategies for large area and solid state devices,” the researchers noted in their paper published in December 6 issue of Nano Letters. Reviewing the study, S Venugopal, assistant professor at the department of Chemical Engineering, Indian Institute of Science, Bengaluru, says, “The overall efficiency of converting light to electricity is one per cent which is five times lower than quantum dot-sensitised films developed earlier.” The advance made in this study is the ability to sensitise TiO2 colloids prior to application (painting, spreading). This is a small step in the right direction, in terms of processing ease, but not yet solar cell paint,” he adds.

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