Solar_cells课件共25页
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Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Appealing Characteristics
Consumes no fuel No pollution Wide power-handling capabilities High power-to-weight ratio
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Tandem Cells
Current output matched for individual cells Ideal efficiency for infinite stack is 86.8% GaInP/GaAs/Ge tandem cells (efficiency 40%)
Solar Energy Spectrum
Power reaching earth 1.37 KW/m2
Air Mass
Amount of air mass through which light pass Atmosphere can cut solar energy reaching earth
CdTe/CdS Solar Cell
CdTe : Bandgap 1.5 eV; Absorption coefficient 10 times that of Si
CdS : Bandgap 2.5 eV; Acts as window layer Limitation : Poor contact quality with p-CdTe (~ 0.1 Wcm2)
by 50% and more
Solar cell – Working Principle
l Operating diode in fourth quadrant generates power
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Thin Film Solar Cells
Produced from cheaper polycrystalline materials and glass
High optical absorption coefficients Bandgap suited to solar spectrum
Back Surface Fields
Most carriers are generated in thicker p region Electrons are repelled by p-p+ junction field
Schottky Barrier Cell
Principle similar to p-n junction cell Cheap and easy alternative to traditional cell Limitations: Conducting grid on top of metal layer Surface damage due to high temperature in
grid-attachment technique
Grooved Junction Cell
Higher p-n junction area High efficiency ( > 20%)
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Intermediate band formed by impurity levels. Process 3 also assisted by phonons Limiting efficiency is 86.8%
Multiple Quantum Well
Principle of operation similar to multiband cells
Inverted Thin Film Cell
p-diamond ( 5.5 eV) as a window layer n-CdTe layer as an absorption layer
Efficiency Losses in Solar Cell
1 = Thermalization loss 2 and 3 = Junction and contact voltage loss 4 = Recombination loss
Multiple E-H pairs
Many E-H pairs created by incident photon through impact ionization of hot carriers
Theoretical efficiency is 85.9%
Multiband Cells
Solar_cells课件
41、俯仰终宇宙，不乐复何如。 42、夏日长抱饥，寒夜无被眠。 43、不戚戚于贫贱，不汲汲于富贵。 44、欲言无予和，挥杯劝孤影。 45、盛年不重来，一日难再晨。及时 当勉励 ，岁月 不待人 。
Solar cells
hygy1688 衬塑复合管 涂塑复合管 钢塑复合管 消防涂覆钢管
Thermophotonic Cells
Heated semiconductor emits narrow bandwidth radiations
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Appealing Characteristics
Consumes no fuel No pollution Wide power-handling capabilities High power-to-weight ratio
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Tandem Cells
Current output matched for individual cells Ideal efficiency for infinite stack is 86.8% GaInP/GaAs/Ge tandem cells (efficiency 40%)
Solar Energy Spectrum
Power reaching earth 1.37 KW/m2
Air Mass
Amount of air mass through which light pass Atmosphere can cut solar energy reaching earth
CdTe/CdS Solar Cell
CdTe : Bandgap 1.5 eV; Absorption coefficient 10 times that of Si
CdS : Bandgap 2.5 eV; Acts as window layer Limitation : Poor contact quality with p-CdTe (~ 0.1 Wcm2)
by 50% and more
Solar cell – Working Principle
l Operating diode in fourth quadrant generates power
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Thin Film Solar Cells
Produced from cheaper polycrystalline materials and glass
High optical absorption coefficients Bandgap suited to solar spectrum
Back Surface Fields
Most carriers are generated in thicker p region Electrons are repelled by p-p+ junction field
Schottky Barrier Cell
Principle similar to p-n junction cell Cheap and easy alternative to traditional cell Limitations: Conducting grid on top of metal layer Surface damage due to high temperature in
grid-attachment technique
Grooved Junction Cell
Higher p-n junction area High efficiency ( > 20%)
Overview
Solar cell fundamentals Novel solar cell structures Thin film solar cells Next generation solar cell
Intermediate band formed by impurity levels. Process 3 also assisted by phonons Limiting efficiency is 86.8%
Multiple Quantum Well
Principle of operation similar to multiband cells
Inverted Thin Film Cell
p-diamond ( 5.5 eV) as a window layer n-CdTe layer as an absorption layer
Efficiency Losses in Solar Cell
1 = Thermalization loss 2 and 3 = Junction and contact voltage loss 4 = Recombination loss
Multiple E-H pairs
Many E-H pairs created by incident photon through impact ionization of hot carriers
Theoretical efficiency is 85.9%
Multiband Cells
Solar_cells课件
41、俯仰终宇宙，不乐复何如。 42、夏日长抱饥，寒夜无被眠。 43、不戚戚于贫贱，不汲汲于富贵。 44、欲言无予和，挥杯劝孤影。 45、盛年不重来，一日难再晨。及时 当勉励 ，岁月 不待人 。
Solar cells
hygy1688 衬塑复合管 涂塑复合管 钢塑复合管 消防涂覆钢管
Thermophotonic Cells
Heated semiconductor emits narrow bandwidth radiations