grapa.datatypes.curveEQE.CurveEQE

class grapa.datatypes.curveEQE.CurveEQE(data, attributes, silent=False)

Bases: Curve

CurveEQE offer basic treatment of (external) quantum efficiency curves of solar cells. Input units should be in [nm] and values within [0-1]. If needed, CurveSpectrum can convert [eV] in [nm].

__init__(data, attributes, silent=False)

Methods

`CurveEQE_absorptionEdge`(thickness, intensity0)	CdS estimate: returns a Curve for quick-and-dirty estimate layer thickness, e.g. CdS.
`CurveEQE_bandgapLog`([ylim, silent])	Performs fit of the low-energy side of EQE with modified Tauc formula (linear relation in (eV * ln(1 - EQE))^2 vs eV.
`CurveEQE_bandgapTauc`([ylim, silent])	Performs fit of the low-energy side of EQE with Tauc formula (linear relation
`CurveEQE_derivativeanalysis`([sgwidth, ...])	Bandgap derivative: Computes the bandgap and other derived data based on the Savitzky-Golay derivative dEQE/dE.
`CurveUrbachEnergy`(roi_ev)	Exponential decay: to obtain a measure of the sub-bandgap disorder tails.
`ERE`(voc, T[, Emin, EminUnit, fg, bandgap, ...])	ERE: Computes the External Radiative Efficiency from the EQE curve and the cell Voc.
`ERE_GUI`(voc, T[, Emin, EminUnit, fg, bandgap])	Computes the External Radiative Efficiency from the EQE curve and the cell Voc.
`__init__`(data, attributes[, silent])
`alterListGUI`()	Determines the possible curve visualisations.
`currentCalc`([roi, interpolatekind, ...])	Computes the current EQE current using AM1.5 spectrum (or another if selected).
`deltavocrad_sigma`(sigma[, T])
`derivative_bandgapmax`([sgwidth, sgdegree, ...])	Computes the bandgap based on the Savitzky-Golay derivative peak of derivative.
`derivative_bandgappvrau`([sgwidth, sgdegree, ...])	PV bandgap based on Rau et al. PRA 2017 (weighted energy over peak FWHM) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016 Assumes input energy data actually given in nm Returns: bandgap value (float), x, y (base for calculation).
`derivative_savgol`([sgwidth, sgdegree, roi])	Returns a reduced x,y range and the Savitzky-Golay derivative sgwidth, sgdegree: width and degree of Savitzky-Golay roi: range of interest [nmmin, nmmax]
`derivative_sigmabestguess`([sgwidth, ...])
`fit_resamplex`(deltax)
`funcListGUI`(**kwargs)	Fills in the Curve actions specific to the Curve type. Retuns a list, which elements are instances of FuncGUI, or (old style): ::.
`func_absorptionedge`(nm, thickness, intensity0)
`func_bandgapTaucCurve`(nm, *bandgap)
`func_bandgapTaucCurveLog`(nm, *bandgap)
`func_gaussian_a`(x, a, x0, sigma, *_args)	A simple gaussian formula to fit the derivative peak The amplitude parameter is peak value i.e. not the function integral _args will be ignored.
`func_gaussian_a_ev`(xnm, a, x0ev, sigmaev, *_args)	A simple gaussian formula to fit the derivative peak.
`print_popt_func_gaussian_a_ev`(popt[, text])	formatted printout of bandgap, sigma, Vocrad loss based on _popt
`reference_curve`(file)	Returns a reference spectrum (spectral photon irradiance) based on the provided file name.
`updateFitParam`(args, *kwargs)	Override.
`updateFitParamFormatPopt`(f, param)	override, for func_absorptionedge
`vocloss_shortcircuit`([bandgap, jsc, T, silent])	Calculation of DeltaV_{OC}^{JSc}, short-circuit loss term to Voc, as Jsc < JscSQ According to equation inline, slightly after Eq 11 in paper Rau PRA 2017 https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016 - bandgap: unit eV.

Attributes

`AXISLABELS_X`
`AXISLABELS_Y`
`BB_FG`
`CURVE`
`FORMAT_AUTOLABEL`
`REF_AM0`
`REF_AM0_FILE`
`REF_AM15`
`REF_AM15_FILE`
`REF_SPECTRA`
`REF_SPECTRA_FILE`
`SG_DEGREE`
`SG_WIDTH`
`SHOCKLEYQUEISSER`
`SHOCKLEYQUEISSER_FILE`
`UNIT_LOOKUP_Y`

CurveEQE_absorptionEdge(thickness: float, intensity0: float, material: str = 'CdS')

CdS estimate: returns a Curve for quick-and-dirty estimate layer thickness, e.g. CdS. The Curve represents the light transmitted through the layer and is computed from Beer-Lambert law as intensity0 * exp(-alpha * thickness), with alpha computed from k imaginary refractive index of material.

Parameters:

thickness – layer thickness, in nm
intensity0 – amount of light entering the layer. Default: 1
material – data is provided for ‘CdS’. A file path might be provided instead, with a file containing k data in a 2-column file (nm, k)

Returns:

a Curve for crude estimation of the absorption in an optical layer.

CurveEQE_bandgapLog(ylim=None, silent=True)

Performs fit of the low-energy side of EQE with modified Tauc formula (linear relation in (eV * ln(1 - EQE))^2 vs eV. In principle more exact, however highly sensitive to reflective and collection losses, therefore less robust than (eV * EQE)^2.

Parameters:

ylim – Relative fractions of EQE values to consider for the fit. By default, [0.25, 0.70].
silent – if False, prints additional information.

Returns:

a Curve with fit parameters and fitted datapoints

CurveEQE_bandgapTauc(ylim=None, silent=True)

Performs fit of the low-energy side of EQE with Tauc formula (linear relation: (eV * EQE)**2 vs eV)

Parameters:

ylim – Relative fractions of EQE values to consider for the fit. By default, [0.25, 0.70].
silent – if False, prints additional information.

Returns:

a Curve with fit parameters and fitted datapoints

CurveEQE_derivativeanalysis(sgwidth: int = None, sgdegree: int = None, roi=None, silent: bool = True) → list

Bandgap derivative: Computes the bandgap and other derived data based on the Savitzky-Golay derivative dEQE/dE. Are implemented:

Peak of derivative, based on a gaussian fit to few points around the peak,
PV bandgap based on Rau et al. PRA 2017 (weighted energy over peak FWHM) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016
Best guess for sigma value, based on gaussian fit with wider fit range

Parameters:

sgwidth – width of Savitzky-Golay filter. Default 5.
sgdegree – degree of Savitzky-Golay filter. Default 3. Parameter values (w,d) = (3,1) fall back onto the symmetrical discrete difference.
roi – range of interest. [nm_min, nm_max]
silent – if False, prints additional information.

Returns:

a list of Curves: the derivative, as well as auxiliary Curves showing the data on which the bandgap is computed. The computed bandgap values can be retrieved in the last Curve attributes.

CurveUrbachEnergy(roi_ev: list)

Exponential decay: to obtain a measure of the sub-bandgap disorder tails. The values are typically fitted at too high energies to be the Urbach tail as can be characterized from high-sensitivity PL spectroscopy. Instead, one obtains slightly higher values, with a contribution from bandgap distributions.

Parameters:: roi_ev – limits to the fitted data, in eV. [ev_min, eV_max]
Returns:: the fit as a Curve, giving exponential decay (proxy to Urbach energy).

ERE(voc: float, T: float, Emin='auto', EminUnit='nm', fg=2, bandgap=None, silent=True)

ERE: Computes the External Radiative Efficiency from the EQE curve and the cell Voc. Ref: Green M. A., Prog. Photovolt: Res. Appl. 2012; 20:472-476 The more complete calculation is also provided from Rau et al., Phys. Rev. Applied 7, 044016 (2017) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016 Returns ERE, and a Curve showing the integrant.

Parameters:

voc – cell Voc voltage in [V]
T – temperature in [K]
Emin – min energy on which the integral is computed. Unit: nm or eV.
EminUnit – ‘eV’ if Emin is given in eV, ‘nm’ otherwise. Default ‘nm’
fg – Ruhle’s geometrical factor. 2 for initial Shockley-Queisser derivation, 1 for hemispherical emission (i.e. back reflector)
bandgap – in eV. if not provided, determines bandgap by derivative method
silent – if False, prints additional information

Returns:

ERE, qe_led, and a list of Curves - the last one contains all values

ERE_GUI(voc, T, Emin='auto', EminUnit='nm', fg=2, bandgap=None)

Computes the External Radiative Efficiency from the EQE curve and the cell Voc. Ref: Green M. A., Prog. Photovolt: Res. Appl. 2012; 20:472-476 The more complete calculation is also provided from Rau et al., Phys. Rev. Applied 7, 044016 (2017) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016

Parameters:

voc – cell Voc voltage in [V]
T – temperature in [K]
Emin – min energy on which the integral is computed. Unit: nm or eV.
EminUnit – ‘eV’ if Emin is given in eV, ‘nm’ otherwise. Default ‘nm’
fg – Ruhle’s geometrical factor. 2 for initial Shockley-Queisser derivation, 1 for hemispherical emission (i.e. back reflector)
bandgap – in eV. if not provided, determines PV bandgap by derivative.

Returns:

a list of Curves - the last one contains all values

alterListGUI(): Determines the possible curve visualisations. One element has the form: AlterListItem(‘Label GUI’, [‘alter_x’, ‘alter_y’], ‘semilogx’, “print help doc”) By default only neutral (i.e. raw data) is provided

currentCalc(roi=None, interpolatekind='linear', spectralPhotonIrrad=None, showintegratedcurrent=False, silent=False, if_gui=False)

Computes the current EQE current using AM1.5 spectrum (or another if selected). Assumes the EQE values are in range [0,1] and NOT [0,100].

Parameters:

roi – [nm_min, nm_max]
interpolatekind – order for interpolation of EQE data. default ‘linear’.
spectralPhotonIrrad – filename in folder datatypes. If None, uses AM1.5G.
showintegratedcurrent – returns the integrated current versus wavelength.
silent – If False, prints additional information.
if_gui – True will print the value, False will return the value.

derivative_bandgapmax(sgwidth=None, sgdegree=None, x_y_savgol=None, roi=None, silent=True)

Computes the bandgap based on the Savitzky-Golay derivative peak of derivative. The peak is located based on a gaussian fit to few points near peak values.

Parameters:

sgwidth –
1. Parameters of Savitzky-Golay filtering
sgdegree – 3
x_y_savgol – (optional) to avoid calculating twice if already computed somewhere else
roi – [nmmin, nmmax]
silent – if False, prints additional information

Returns:

fit results popt, x in fit range

derivative_bandgappvrau(sgwidth=None, sgdegree=None, x_y_savgol=None, roi=None, silent=True): PV bandgap based on Rau et al. PRA 2017 (weighted energy over peak FWHM) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016 Assumes input energy data actually given in nm Returns: bandgap value (float), x, y (base for calculation)

derivative_savgol(sgwidth=None, sgdegree=None, roi=None): Returns a reduced x,y range and the Savitzky-Golay derivative sgwidth, sgdegree: width and degree of Savitzky-Golay roi: range of interest [nmmin, nmmax]

funcListGUI(**kwargs)

Fills in the Curve actions specific to the Curve type. Retuns a list, which elements are instances of FuncGUI, or (old style):

[func,
 'Button text',
 ['label 1', 'label 2', ...],
 ['value 1', 'value 2', ...],
 {'hiddenvar1': 'value1', ...}, (optional)
 [dictFieldAttributes, {}, ...]] (optional)

By default, returns quick modifs for offset and muloffset (if already set), and a help for some plot types (errorbar, scatter).

Parameters:: kwargs – this function should be called specifying kwargs[‘graph’] the graph self is embedded in, and kwargs[‘graph_i’] as position of self in graph.

static func_gaussian_a(x, a, x0, sigma, *_args): A simple gaussian formula to fit the derivative peak The amplitude parameter is peak value i.e. not the function integral _args will be ignored. Because GUI may send more than required parameters

static func_gaussian_a_ev(xnm, a, x0ev, sigmaev, *_args): A simple gaussian formula to fit the derivative peak. Amplitude parameter is peak value i.e. not the function integral args: will be ignored. Because GUI may send more than required parameters.

classmethod print_popt_func_gaussian_a_ev(popt, text='Bandgap'): formatted printout of bandgap, sigma, Vocrad loss based on _popt

classmethod reference_curve(file: str)

Returns a reference spectrum (spectral photon irradiance) based on the provided file name.

Parameters:: file – (str) The name of the file containing the reference spectrum data. The file should be located in the same directory as the script.
Returns:: A Curve object containing the reference spectrum data, or None if file not found or an error occurs while loading the file

updateFitParam(*args, **kwargs): Override. Additional behavior when changing gaussian fit to derivative

updateFitParamFormatPopt(f, param): override, for func_absorptionedge

vocloss_shortcircuit(bandgap=None, jsc=None, T=298.15, silent=False): Calculation of DeltaV_{OC}^{JSc}, short-circuit loss term to Voc, as Jsc < JscSQ According to equation inline, slightly after Eq 11 in paper Rau PRA 2017 https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.7.044016 - bandgap: unit eV. If not provided, computed from derivative method. - jsc: unit mA/cm2. If not provided, computed with default parameters. - T: unit K. if not provided, STC value (298.15 K)