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  • perovskite photovoltaic solar cells : a short general overview power point presentation
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  • Dear colleague,

    I have gone through your presentation. It's an excellent work
    The presentation, however, may be expanded by you and me collectively to include the origins of high efficiency of these solar cells. For example, the origins of the long diffusion coefficient, and high mobility of carrier in these materials. Although our audience would be changed a bit as we would be addressing the graduate students and faculty. However, we may co-author a good review paper leading to an advancement of the science, engineering and technology involved in solar cells.

    You can contact me on for further correspondence please.

    Best of luck,

    Dr Ghous B Narejo,

    CTO, SWESTN Emerging Technologies,
    Renewable, Environment, Health
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  • A clear glass tube surrounds a dark tube. A vacuum exists between the dark tube and the clear glass, reducing heat transfer and energy loss. The dark tube contains a fluid that is pumped to a heat exchanger to heat water.
  • Parabolic trough systems are expensive. Current research lies in the following areas:Improved reflectivity of parabolic mirrorsReduced manufacturing cost of troughsSelf-cleaning (coatings)Replacing two-tank systems with one-tank thermocline systemsReducing costs of production and integration to be competitive with other energy sources
  • Concentrated photovoltaics focus light onto PV cells with lenses or mirrors. The PV cells used are high-efficiency and typically much more expensive than conventional PV systems. However, because the light is focused on the PV cell, a smaller cell or array can be used, keeping costs down. Concentrating photovoltaic technology offers the following advantages:Potential for solar cell efficiencies greater than 40%No moving partsNo intervening heat transfer surfaceNear-ambient temperature operationNo thermal mass; fast responseReduction in costs of cells relative to opticsScalable to a range of sizes.
  • Focusing solar radiation onto a stirling engine will cause it to rotate the fly wheel, and connecting it to a turbine will generate electricity.
  • Tracking PV heliostats move on two axes to accommodate both the tilt of the earth throughout the year as well as the rotation of the earth throughout the day. The angles are adjusted to ensure the maximum intensity of insolation is achieved.The major benefit of tracking photovoltaics is that they can generate more energy per acre than fixed-angle photovoltaics. Even though they cost more to manufacture and install, the increased amount of energy they can produce reduces the payback period.
  • Silicon crystal photovoltaics continue to be the primary materials used in PV systems installed today. Research at NREL and other facilities is focusing on three major areas:Thin crystalline silicon acquired via epitaxial growth. Gaseous silicon compounds are passed over a very hot substrate and the crystals that form are in a controlled orientation. Finding high efficiency and low-cost substrates for thin film applications are key.Crystallized polysilicon layersNanoscale siliconScientists at NREL are also studying new, non-crystalline materials for manufacturing photovoltaics. Organic photovoltaic (OPV) cells have an extremely broad application potential because of their flexibility, ability to absorb in different colors, and make efficient transparent devices. These properties make OPV attractive for integration into building design.
  • Solar Power: THE PEROVSKITE

    1. 1. Re s e a r c h e r :
    2. 2. A New Solar Material Shows Its Potential A new material described in Nature adds to the momentum suggesting a new path to high-efficiency, inexpensive solar cells. By: Kevin Bullis November 10, 2013
    3. 3. “The sun will be the fuel of the future” -Anonymous, 1876, Popular Science
    4. 4. Solar Power, along with wind, hydroelectric, wave, biomass account for most of the renewable energy source available to use. It can be collected by human through photovoltaics and heat engines (concentrating heat panel ).
    5. 5. Or solar cell, is the direct conversion of light into electricity at the atomic level. A photovoltaic cell (PV) is a device that converts sun light into direct current through photoelectric effect. The photoelectric effect causes some materials to absorb light photons and convert them into electrons.
    6. 6. Individual PV cells are electricity-producing devices that are made of semiconductor materials. The photoelectric effect is first noted by French physicist Edmund Bequerel in 1839. The first PV cell was constructed by Charles Fritts in 1880. The first major usage of PV cell is on the Vanguard I satellite in 1958.
    7. 7. PV cells come in different shapes and sizes. It can be the size of a stape, or several inches. Depending on the level of need, the PV cells can be put together to form a field or a single module for residential usage. In general, photovoltaic modules and arrays produce DC electricity.
    8. 8. Solar panels
    9. 9. Concentrating Solar Power or (CSP) is another way of collecting energy from sun. Concentrating Solar Power system is made up of lenses, mirrors, and tracking systems focusing a large amount of sunlight into a smaller beam. The concentrated light heat up a working fluid and is then used as the heat source for power generation or energy storage.
    10. 10. The most developed methods for CSP are solar trough, parabolic dish, and solar power tower. Unlike photovoltaics, CSP can be used at a larger scale and is more energy efficient. Unlike PV which converts solar ray directly into electricity, CSP system use heat to generate a motor in order to create energy.
    11. 11. A diagram of a parabolic trough solar farm (top), and an end view of how a parabolic collector focuses sunlight onto its focal point.
    12. 12. Lets watch this video… SCI 101VIDEOEnergy 101- Solar Power.FLV
    13. 13.  Improve efficiency  Improve overall cost and cost-per-kWh  Reduce impact of materials used  Improve viability in less sunny conditions
    14. 14. NEWER TECHNOLOGIES Solar Thermal Vacuum Tubes Solar Thermal Troughs Solar Stirling Engines Tracking Solar Heliostats Thin-film Flexible Photovoltaics Multi-junction Photovoltaics Vehicle-to-Grid Technologies Space-based Photovoltaics
    15. 15. Solar Vacuum Tubes (water heating)
    16. 16. Trough Concentration (Kramer Junc.)
    17. 17. Concentrated Photovoltaics
    18. 18. Solar Stirling Engine
    19. 19. Tracking Photovoltaic Heliostats
    20. 20. Improving Photovoltaics First-generation (silicon) Thin c-Si via epitaxial growth Crystallized polysilicon layers Nanoscale silicon Second-generation (“thin film”) Less efficient, more flexible and less expensive than 1st gen CdTe and CIGS Third-generation Solar ink, solar dye, conductive plastic
    21. 21. Solar cells that use the material “can be made with very simple and potentially very cheap technology, and the efficiency is rising very dramatically,” Martin Green says.
    22. 22. An article in the journal Nature describes the materials—a modified form of a class of compounds called PEROVSKITES, which have a particular crystalline structure.
    24. 24. Let the Photovoltaic Battle Begin!!!
    25. 25. Perovskites are a plentiful mineral that have been interesting to material scientists in the exploration of superconductivity, magnetoresistance, ionic conductivity, and a multitude of dielectric properties, which are of great importance in microelectronics and telecommunication.
    26. 26. PEROVSKITE is very good at absorbing light. PEROVSKITE use less than one micrometer of material to capture the same amount of sunlight. PEROVSKITE is a semiconductor, thus good at transporting the electric charge created when light hits it.
    27. 27. A team of physicists working at Oxford University in the UK has found that it's possible to use some types of perovskite as a replacement for thin film silicon cells using the same basic processing technique and still get power efficiencies of 15 percent.
    28. 28. Prof Subodh Mhaisalkar (left) and Dr Nripan Mathews (right) are holding the new Perosvkite solar cells made in NTU labs and hopes to develop into a solar cell module, as held by Prof Sum Tze Chien (centre).
    29. 29. In their paper published in the journal Nature, the researchers report that they have discovered that using a bubble-like nanostructure, or an insulating scaffold to create thin film solar cells is unnecessary—the new kind of cell is able to serve as a semiconductor on its own.
    30. 30. FACTS IN PEROVSKITE Organometal halide perovskites have recently emerged as a promising material for high-efficiency nanostructured devices. A simple planar heterojunction solar cell incorporating vapour-deposited perovskite as the absorbing layer can have solar-to-electrical power conversion efficiencies of over 15 percent. Perovskite absorbers can function at the highest efficiencies in simplified device architectures, without the need for complex nanostructures.
    31. 31. Generation solar cell, made from organicinorganic hybrid perovskite materials, is about five times cheaper than current thin-film solar cells, due to a simpler solution-based manufacturing process.
    32. 32. These perovskites tend to have high charge-carrier mobilities. High mobility is important because, together with high charge carrier lifetimes, it means that the light-generated electrons and holes can move large enough distances to be extracted as current, instead of losing their energy as heat within the cell.
    33. 33. The team of eight researchers led by Assistant Professor Sum Tze Chien and Dr Nripan Mathews had worked closely with NTU Visiting Professor Michael Grätzel, who currently holds the record for perovskite solar cell efficiency of 15 per cent, and is a co-author of the paper. Prof Grätzel, who is based at the Swiss Federal Institute of Technology in Lausanne (EPFL), has won multiple awards for his invention of dyesensitised solar cells.
    34. 34. The high sunlight-toelectricity efficiency of perovskite solar cells places it in direct competition with thin film solar cells which are already in the market and have efficiencies close to 20 per cent.
    35. 35. "In our work, we utilize ultrafast lasers to study the perovskite materials. We tracked how fast these materials react to light in quadrillionths of a second (roughly 100 billion times faster than a camera flash)," said the Singaporean photophysics expert from NTU's School of Physical and Mathematical Sciences.
    36. 36. The NTU physicist added that this unique characteristic of perovskite is quite remarkable since it is made from a simple solution method that normally produces low quality materials.
    37. 37. "Now that we know exactly how perovskite materials behave and work, we will be able to tweak the performance of the new solar cells and improve its efficiency, hopefully reaching or even exceeding the performance of today's thin-film solar cells," said Dr Mathews.
    38. 38. • "The excellent properties of these materials, allow us to make light weight, flexible solar cells on plastic using cheap processes without sacrificing the good sunlight conversion efficiency,“ said Professor Subodh Mhaisalkar.
    39. 39. Researchers developing the technology say that it could lead to solar panels that cost just 10 to 20 cents per watt. Solar panels now typically cost about 75 cents a watt, and the U.S. Department of Energy says 50 cents per watt will allow solar power to compete with fossil fuel.
    40. 40. “The material is dirt cheap,” says Michael Grätzel, who is famous within the solar industry for inventing a type of solar. His group has produced the most efficient perovskite solar cells so far— they convert 15 percent of the energy in sunlight into electricity, far more than other cheap-to-make solar cells.
    41. 41. Based on its performance so far, and on its known light-conversion properties, researchers say its efficiency could easily rise as high as 20 to 25 percent, which is as good as the record efficiencies (typically achieved in labs) of the most common types of solar cells today.
    42. 42. Perovskite solar cells can be made by spreading the pigment on a sheet of glass or metal foil, along with a few other layers of material that facilitate the movement of electrons through the cell.
    43. 43. The manufacturing process for perovskite solar cells— which can be as simple as spreading a liquid over a surface or can involve vapor deposition, another largescale manufacturing process—is expected to be easy.
    44. 44. • The researchers also showed that it is relatively easy to modify the material so that it efficiently converts different wavelengths of light into electricity. It could be possible to form a solar cell with different layers, each designed for a specific part of the solar spectrum, something that could greatly improve efficiency compared to conventional solar cells
    45. 45. Dr. Henry Snaith from Oxford University holding a perovskite solar cell
    46. 46. When perovskites were first tried in solar cells in 2009, efficiencies were low—they only converted about 3.5 percent of the energy in sunlight into electricity. Why do you think?
    47. 47. The cells also didn’t last very long, since a liquid electrolyte dissolved the perovskite. But last year a couple of technical innovations—ways to replace a liquid electrolyte with solid materials—solved those problems and started researchers on a race to produce ever-more-efficient solar cells.
    48. 48. Lets watch this video… SCI 101VIDEOMaking a perovskite solar cell.FLV
    49. 49. “Between 2009 and 2012 there was only one paper. Then in the end of the summer of 2012 it all kicked off,” Snaith says. Efficiencies quickly doubled and then doubled again. And the efficiency is expected to keep growing as researchers apply techniques that have been demonstrated to improve the efficiency of other solar cells.
    50. 50. • The perovskite material described in Nature has properties that could lead to solar cells that can convert over half of the energy in sunlight directly into electricity, says Andrew Rappe, co-director of Pennergy, a center for energy innovation at the University of Pennsylvania, and one of the new report’s authors.
    51. 51. • That’s more than twice as efficient as conventional solar cells. Such high efficiency would cut in half the number of solar cells needed to produce a given amount of power. Besides reducing the cost of solar panels, this would greatly reduce installation costs, which now account for most of the cost of a new solar system.
    52. 52. Unlike conventional solar cell materials, the new material doesn’t require an electric field to produce an electrical current. This reduces the amount of material needed and produces higher voltages, which can help increase power output. While other materials have been shown to produce current without the aid of an electric field, the new material is the first to also respond well to visible light, making it relevant for solar cells
    53. 53. Solar power helps to slow/stop global warming. Solar power is a completely renewable resource. Solar power saves society billions or trillions of dollars. Solar power saves you money. Solar power provides energy reliability. Solar power provides energy security. Solar power provides energy independence. Solar power creates absolutely no noise at all
    54. 54. Solar power cannot be harnessed during a storm, on a cloudy day or at night. This limits how much power can be saved for future days. Some days you may still need to rely on oil to power your home.
    55. 55. REFERENCES • kite-solar-cells-reach-15.html • summary • •