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Tag: solar cells

  • Inexpensive Solar Cells Made From Carbon Nanotubes

    Scientists at Rice University are developing new solar cells from single-wall nano tube arrays. These nano-tubes, grown in a process invented at Rice, are more electroactive and cheaper to make than current dye-sensitized solar cells (DSC). These solar cells typically use platinum as a catalyst, making solar power a not-so-cheap alternative.

    The new nanotube solar cells will pave the way for a low-cost highly efficient alternative to silicon based cells, says Jun Lou and Hong Lin, the scientists who released their findings in Nature Scientific Reports. I suggest an advanced engineering degree if you plan on checking it out. Not an easy read.

    To put it in layman’s terms, DSCs, as mentioned above, use a catalyst and an electrolyte to convert photon energy from the sun into electric energy we use every day. The scientists at Rice have developed a new catalyst in the form of carbon nanotubes, and are pairing that with a new sulfide based electrolyte to make the process more efficient.

    DSCs are typically easier to manufacture than an alternative form of solar cell called solid-state photovoltaic cells, but they aren’t as efficient. The scientists at Rice are attempting to up the efficiency of DSCs with this new carbon nanotube technology while retaining the ease of manufacturing DSCs are known for.

    In tests, resistance between the components of these new solar cells is very low, making for a more efficient cell.

    As Lou explains in his report, the technology is very promising, but there is still work to be done: “The carbon nanotube-to-current collector still has a pretty large contact resistance, and the effects of structural defects in carbon nanotubes on their corresponding performance are not fully understood, but we believe once we optimize everything, we’re going to get decent efficiency and make the whole thing very affordable,” Lou says.

    One of the largest deterrents for the use of solar energy is it’s high start-up cost. If Lou and Lin complete their work, creating a low cost alternative to current solar cells, it could welcome a whole new wave of consumers trying out the technology for themselves. A low cost and self-regenerating energy source is exactly what we need right now.

  • Solar Cells That Make More Power

    Scientists have developed a new kind of solar cell which could capture significantly more of the energy from the sun than current cells. These new solar cells could increase the maximum efficiency of solar panels by over 25%, according to scientists from the University of Cambridge.

    Solar panels work by absorbing energy from particles of light, called photons, which then generate electrons to create electricity. Traditional solar cells are only capable of capturing part of the light from the sun and much of the energy of the absorbed light, particularly of the blue photons, is lost as heat. This inability to extract the full energy of all of the different colors of light at once means that traditional solar cells are incapable of converting more than 34% of the available sunlight into electrical power.

    The Cambridge team led by Professor Neil Greenham and Professor Sir Richard Friend has developed a hybrid cell which absorbs red light and harnesses the extra energy of blue light to boost the electrical current. Typically, a solar cell generates a single electron for each photon captured. However, by adding pentacene, an organic semiconductor, the solar cells can generate two electrons for every photon from the blue light spectrum. This could enable the cells to capture 44% of the incoming solar energy.