I am starting to simulate the anti-reflection coating (ARC) for solar cells but I found some problems that I can't answer:
1, For solar cell without ARC, I tried to put the light source below (0.01 nm) the surface of the solar cell. But the performances are still the same. Does this mean there are no reflection on the silicon surface?
2, I tried to use different thickness of Si3N4 as ARC. For convenience I ignored the absorption of Si3N4. When I put the light source above the ARC, the performance decrease about 10%~15% mainly due to Jsc decrease. When I put the light source below the surface of Si3N4, the performance barely changes. I assume that means Si3N4 reflected about 10% of light but didn't help with the anti-reflection (many thickness tested from 60 to 100 nm).
My sdevice code is showing below.
File {
* input files:
Grid= "n@previous@_msh.tdr" #
Parameter= "@parameter@"
PMIPath = "./pmi/"
#OptGenTransientScaling= "./mesh/spettri/time.txt"
illuminationSpectrum ="./mesh/spettri/am15g.txt"
* output files:
Plot= "@tdrdat@"
Current="@plot@"
Output= "@log@"
} # END FILE
Electrode {
{ Name="top" Voltage=0.0 }
{ Name="bottom" Voltage=0.0 }
}
Physics{
Temperature= 300
Fermi
AreaFactcor=1e9
Mobility (constantMobility) #Arora
Recombination(SRH(DopingDependence) Auger)
EffectiveIntrinsicDensity (BandGapNarrowing(SlotBoom))
}
RayTraceBC {
{ Name= "top" transmittivity=1 } #
{ Name= "bottom" reflectivity= 0 transmittivity= 1 } #
}
############################ OTTICA ########################
Physics {
Optics (
ComplexRefractiveIndex (WavelengthDep(real imag))
OpticalGeneration (
QuantumYield (StepFunction(EffectiveBandgap))
ComputeFromSpectrum()
) # end Opticalgeneration
Excitation
(
Theta= 0 * Normal incidence
Polarization= 0.5 * Unpolarized light
Window ("L1")
(
Origin = ( 0 ,-205)
Line (
X1 = 0
X2 = 10000
) * end Line
) * end window
) * end Excitation
OpticalSolver (
Raytracing (
MinIntensity = 1e-14
RayDistribution(
Mode= AutoPopulate
NumberOfRays= 500
)
) *end Raytracing
) * end OpticalSolver
) #end optics
} #Physics
############################### FINE OTTICA ###################################
Plot {
ComplexRefractiveIndex QuantumYield AbsorbedPhotonDensity
SRHRecombination SurfaceRecombination RadiativeRecombination
eBand2BandGeneration TotalRecombination
OpticalIntensity Opticalgeneration OpticalField
CurrentPotential Potential ElectricField
SpaceCharge eDensity hTrappedCharge
current/Vector hCurrent/Vector eCurrent/Vector hMobility eMobility
eVelocity hVelocity eQuasiFermiEnergy hQuasiFermiEnergy
Doping DonorConcentration AcceptorConcentration
BandGap EffectiveBandGap ValenceBandEnergy ConductionBandEnergy
hEnormal hEparallel hGradQuasiFermi eGradQuasiFermi
# eTrappedCharge hTrappedCharge hInterfaceTrappedCharge eInterfaceTrappedCharge
eLifetime hLifetime
}
CurrentPlot {
AbsorbedPhotonDensity(Integrate(Semiconductor))
OpticalGeneration(Integrate(Semiconductor))
SRH (Integrate(Semiconductor))
Auger(Integrate(Semiconductor))
Radiative (Integrate(Semiconductor))
}
######## MATH ######
Math {
Notdamped=100
SubMethod=ParDiSo
Method=Blocked
ExitOnFailure
Iterations= 300
Extrapolate
Derivatives
RelErrControl
Digits= 5
}
########## SOLVE ###################
Solve {
NewCurrentPrefix= "./tmp_"
Poisson
Coupled {Poisson Electron Hole}
Plot (FilePrefix= "BandDiagram@node@")
NewCurrentPrefix=""
Quasistationary
(InitialStep=0.01 Maxstep=0.02 MinStep=0.02
Goal{name="top" voltage= 0.8}
plot{range = (0 1) Intervals = 10 } *5
)
{ Coupled { Poisson Hole Electron}}
} #end solve
Dear Shujian,
welcome,
You need at first to make optical ray tracing for the different structures to see the reflectance and the absorbance in the different layers of solar cells.
Bare silicon has a reflectance of about 30 percent. By adding an antirefecltive coating with the proper tickness the absorbance sinks to about few percent.
The layer thickness of the antirefelctive coating must be about lambda/ 4= almbda0/4 n where n is the refractive index and lambda0 is the free sapce wavelength of the green light.
I invite you to read the book chapter in the link: Chapter Solar cells and arrays: Principles, analysis and design
After making the ray tracing analysis please inform us.
Wish you success
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