/
rcwa.py
executable file
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/
rcwa.py
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from solcore.structure import Layer, Junction, TunnelJunction
from solcore.absorption_calculator import calculate_rat_rcwa, calculate_absorption_profile_rcwa
import numpy as np
import types
from solcore.state import State
rcwa_options = State()
rcwa_options.size = [500, 500]
rcwa_options.orders = 4
rcwa_options.theta = 0
rcwa_options.phi = 0
rcwa_options.pol = 'u'
rcwa_options.parallel = False
rcwa_options.n_jobs = -1
def solve_rcwa(solar_cell, options):
"""Calculates the reflection, transmission and absorption of a solar cell object using the rigorous coupled-wave analysis solver.
:param solar_cell: A solar_cell object
:param options: Options for the solver
:return: None
"""
wl = options.wavelength
solar_cell.wavelength = options.wavelength
parallel = options.parallel
rcwa_options = options.get("rcwa_options", None)
# We include the shadowing losses
initial = (1 - solar_cell.shading) if hasattr(solar_cell, 'shading') else 1
# Now we calculate the absorbed and transmitted light. We first get all the relevant parameters from the objects
all_layers = []
n_layers_junction = []
for j, layer_object in enumerate(solar_cell):
# Attenuation due to absorption in the AR coatings or any layer in the front that is not part of the junction
if type(layer_object) is Layer:
all_layers.append(layer_object)
n_layers_junction.append(1)
# For each junction, and layer within the junction, we get the absorption coefficient and the layer width.
elif type(layer_object) in [TunnelJunction, Junction]:
n_layers_junction.append(len(layer_object))
for i, layer in enumerate(layer_object):
all_layers.append(layer)
# With all the information, we create the optical stack
stack = all_layers
position = options.position * 1e9
substrate = solar_cell.substrate
incidence = solar_cell.incidence
print('Calculating RAT...')
RAT = calculate_rat_rcwa(stack, options.size, options.orders, wl * 1e9, incidence, substrate, theta=options.theta,
phi=options.phi, pol=options.pol, parallel=parallel, user_options=rcwa_options)
print('Calculating absorption profile...')
out = calculate_absorption_profile_rcwa(stack, options.size, options.orders, wl*1e9, RAT['A_pol'],
dist=position, theta=options.theta, phi=options.phi, pol=options.pol, incidence=incidence,
substrate=substrate,
parallel=options.parallel, n_jobs=options.n_jobs, user_options=rcwa_options)
# With all this information, we are ready to calculate the differential absorption function
diff_absorption, all_absorbed = calculate_absorption_rcwa(out, initial)
layer = 0
A_per_layer = np.array(RAT['A_per_layer'].T)
# Each building block (layer or junction) needs to have access to the absorbed light in its region.
# We update each object with that information.
for j in range(len(solar_cell)):
solar_cell[j].diff_absorption = diff_absorption
solar_cell[j].absorbed = types.MethodType(absorbed, solar_cell[j])
solar_cell[j].layer_absorption = initial*np.sum(A_per_layer[layer:(layer+n_layers_junction[j])], axis = 0)
layer = layer + n_layers_junction[j]
solar_cell.reflected = RAT['R'] * initial
solar_cell.absorbed = sum([solar_cell[x].layer_absorption for x in np.arange(len(solar_cell))])
solar_cell.transmitted = initial - solar_cell.reflected - solar_cell.absorbed
def absorbed(self, z):
out = self.diff_absorption(self.offset + z) * (z < self.width)
return out.T
def calculate_absorption_rcwa(tmm_out, initial=1):
all_z = tmm_out['position'] * 1e-9
all_abs = initial * tmm_out['absorption'] / 1e-9
def diff_absorption(z):
idx = all_z.searchsorted(z)
idx = np.where(idx <= len(all_z) - 2, idx, len(all_z) - 2)
try:
z1 = all_z[idx]
z2 = all_z[idx + 1]
f = (z - z1) / (z2 - z1)
out = f * all_abs[:, idx] + (1 - f) * all_abs[:, idx + 1]
except IndexError:
out = all_abs[:, idx]
return out
all_absorbed = np.trapz(diff_absorption(all_z), all_z)
return diff_absorption, all_absorbed