Download - solar cell ppt
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Solar cellsAbhishek Gupta(0905232002) Anamika(0905232005) Ashish Kumar Mishra(0905232008) Vinit Kumar Mishra(1005232903)
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OverviewSolar cell fundamentalsNovel solar cell structuresThin film solar cellsNext generation solar cell
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Appealing CharacteristicsConsumes no fuelNo pollutionWide power-handling capabilitiesHigh power-to-weight ratio
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Solar Energy SpectrumPower reaching earth 1.37 KW/m2
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Air MassAmount of air mass through which light passAtmosphere can cut solar energy reaching earth by 50% and more
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Solar cell Working PrincipleOperating diode in fourth quadrant generates power
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OverviewSolar cell fundamentalsNovel solar cell structuresThin film solar cellsNext generation solar cell
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Back Surface FieldsMost carriers are generated in thicker p regionElectrons are repelled by p-p+ junction field
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Schottky Barrier CellPrinciple similar to p-n junction cellCheap and easy alternative to traditional cellLimitations:Conducting grid on top of metal layerSurface damage due to high temperature in grid-attachment technique
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Grooved Junction CellHigher p-n junction areaHigh efficiency ( > 20%)
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OverviewSolar cell fundamentalsNovel solar cell structuresThin film solar cellsNext generation solar cell
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Thin Film Solar CellsProduced from cheaper polycrystalline materials and glassHigh optical absorption coefficientsBandgap suited to solar spectrum
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CdTe/CdS Solar CellCdTe : Bandgap 1.5 eV; Absorption coefficient 10 times that of SiCdS : Bandgap 2.5 eV; Acts as window layerLimitation : Poor contact quality with p-CdTe (~ 0.1 Wcm2)
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Inverted Thin Film Cellp-diamond (Bandgap 5.5 eV) as a window layern-CdTe layer as an absorption layer
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Efficiency Losses in Solar Cell1 = Thermalization loss 2 and 3 = Junction and contact voltage loss4 = Recombination loss
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OverviewSolar cell fundamentalsNovel solar cell structuresThin film solar cellsNext generation solar cell
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Tandem CellsCurrent output matched for individual cellsIdeal efficiency for infinite stack is 86.8%GaInP/GaAs/Ge tandem cells (efficiency 40%)
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Multiple E-H pairsMany E-H pairs created by incident photon through impact ionization of hot carriersTheoretical efficiency is 85.9%
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Multiband CellsIntermediate band formed by impurity levels.Process 3 also assisted by phononsLimiting efficiency is 86.8%
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Multiple Quantum WellPrinciple of operation similar to multiband cells
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Thermophotonic CellsHeated semiconductor emits narrow bandwidth radiationsDiode with higher temperature has lower voltage
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Thermophotovoltaic CellFilter passes radiations of energy equal to bandgap of solar cell materialEmitter radiation matched with spectral sensitivity of cellHigh Illumination Intensity ( ~ 10 kW/m2 )
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Thermophotovoltaic Cells Efficiency almost twice of ordinary photocell
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The End
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