太阳电池的光衰现象说明

149286 2010/10http://www.materialsnet.com.twAn Introduction of Light-induced Degradation on Silicon Solar CellT. Y. Wang 1 C. L. Sun 2 C. H. Lin 3C. W. Lan 4(GEL/ITRI) 1 2 3 490%(Siemens Process)PSolar photovoltaic (PV) energy will shortly be in great demand, since it is inexhaustible and cleanerthan any conventional energy resources. The global PV production will over 8 GW in 2010 alone, outof which, the majority is the silicon wafer-based solar cells. So far, most of solar grade silicon is from theSiemens process, which is energy intensive and high cost. Therefore, cheaper routes for producingsolar grade silicon are being developed in the PV industries, but the progress in slow. Therefore,seeking a feasible and low-cost route for producing silicon solar cell with high energy transferefficiency is important for the PV industry. Although the solar cell efficiencies made from Cz siliconwafer are already quite high, the light-induced degradation of minority carrier lifetime and cell efficiency,which is caused by a metastable defect under illumination, are still the problem. Far now the methodto avoid light-induced degradation is still under researching./Key Words(Silicon) (Solar Cell) (Degradation)150286 2010/10http://www.materialsnet.com.tw50%50%(1)90%(Czochralski Method; Cz)(Floating Zone Method; FZ)Cz(Casting Method)30%(2)(Light-inducedDegradation or Illumination Degradation)1973 Fischer Pschunder (3)P-type CzBest Research-cell EfficienciesMultijunction ConcentratorsSingle-junction GaAsCrystalline Si CellsThin-Film TechnologiesEmerging PVThree-junction (2-terminal, Monolithic)Two-junction (2-terminal, Monolithic)Single CrystalConcentratorThin FilmSingle CrystalMulticrystallineThick Si FilmCu(In,Ga)Se2CdTeAmorphous Si:H (Stabilized)Nano-, Micro-, Poly-SiMultijunction PolycrystallineDye-sensitized CellsOrganic Cells(Various Technologies)MatsushitaMonosolarBoeingKodakBoeingUniversityof MaineRCA RCA RCA RCARCA RCARCASolarexBoeingKodak Solarex ARCOAMETEKBoeingPhoton EnergyUnited SolarUniversitySo. FloridaEPFLUniversity Linz UniversityLinzGroningenSiemensPlextronicsSharpUnited SolarKaneka(2 μ m on Glass)EPFLBoeing Euro-CISNREL NRELNREL NRELNREL NREL NREL NREL NRELNRELUnited SolarUniv. Stuttgart(45 μ m Thin-filmTransfer)Sharp(Large-area)FhG-ISEFhG-ISEAmonix(92x Conc.)NRELCu(In,Ge)Se2(14x Conc.)UNSWUNSWUNSWUNSWUNSWUNSWUNSW Georgia TechGeorgia Tech SharpVarianStanfordSpireSpireNo. CarolinaState Univ.Westing-houseARCOKopinStanford(140x Conc.)Varian(216x Conc.)NRELNRELJapanEnergySunPower(96x Conc.)NREL/SpectrolabSpectrolabBoeing-Spectrolab NREL(Inverted,Semi-mismatched)NREL(Inverted, Semi-mismatched, 1-sun)Boeing-Spectrolab(Metamorphic) 40.7%33.8%27.6%24.7%20.3%19.9%16.5%12.1%11.1%5.4%1975 1980 1985 1990 1995 2000 2005 2010444036322824201612840Efficiency(%)NREL KonarkaUniv. LinzNREL(CdTe/CIS)AstroPower(Small-area)(2)151286 2010/10http://www.materialsnet.com.tw(200 ° C)1~1.5%(4)-(Boron-oxygen Pair)P-type BB Accepter BSubstitutional(B s) B s(Oi)B s-O 2i (5)(SiO) SiO0.620.610.60VOC(V)36.035.535.034.034.50 1 2 3 4 5 6Time (hour)JSC(mA/cm2)V OCJSC(a)0 1 2 3 4 5 6Time (hour)787674FillFactor(%)17.016.516.015.5Efficiency(%)FFEff(b)(4)SiB sOiO iBs-O 2i (5)152286 2010/10http://www.materialsnet.com.tw(6)(BaCO 3)(BaO)(BaSiO 3)(7)<10ppma15~18 ppmaP-typeP-type(8) V oc(9)P-type(Gallium) P-type(10)(k0 = 0.008)(Phosphorous) N-type N-type(11) N-type P-typeN-type1,000 W/m 20-1-2-3-4RelativeVocDegradation(%)0 200 400 600 800 1000Illumination Time (min)σ = 1.2 ? cm - No Illuminationσ = 1.2 ? cm - 0.5 sunσ = 1.2 ? cm - 1 sunσ = 6.8 ? cm - 1 sun(8)90080070060050040030020010001.00.80.60.40.20.0Ratioτ eff(μs)Before IlluminationAfter Illumination0.8/9.60.77/13.15.4/10.31.2/0.55.2/1.00.69/04.4/03.4/13.85.2/13.722/13.1#1(BCz)#2(BCz)#3(BMCz)#4(BMCz)#5(BMCz)#6(BFz)#7(BFz)#8(Ga Cz)#9(Ga Cz)#10(GaCz)Materialρ base (? cm)/O i (ppm)(9)153286 2010/10http://www.materialsnet.com.twSANYO HITN-type(FZ) FZ0.01 ppma(12) 25% PERL (Passi-vated Emitter and Rear Locally-diffused)FZ (13)(MCz)(<1 ppma)103102101 0 20 40 60 80 100 120 140160 180 970Illumination Time (min)τ b(μs)Cz p-Si10 ? cm, Ga10 ? cm, B1.5 ? cm, B1.0 ? cm, B(10)(14) State A (Annealed State)State B (Degraded State)State B State C (Regenerate State)LimB-doped P-type Cz-Si(3 ? cm)P-doped N-type Cz-Si(3.5 ? cm)100010010Lifetimeτ(μs)20 6 8 104Illumination Time t (h)N-type P-type(11)State A‘ Annealed ’(Inactive)State B‘ Annealed ’(Active)State C‘ Regenerated ’(Inactive)DegradationRedegradationAnnealRegenerationDestabilizationStabilization(14)154286 2010/10http://www.materialsnet.com.tw(15)1 sun 200° C1%P-type1%(15)67567066566065564564065020.520.019.519.0Efficiencyη(%)Open-circuitVoltageVOC(mV) (a)(b)Illumination atRoom TemperatureRISE-EWT Solar CellBulk Material: 1.4- ? cm Cz-SiIllumination Intensity 100 mW/cm 20 1 2 10 15 20 3025Time t (h)1. 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