How can I plot the Shockley Queisser Limit?

I’ve seen this example on MATLAB but I’m not sure how to make this function to plot.

function[data] = ShockleyQueisser(varargin)
%%%%%%%%%% defaults
sun = 'am1.5';
lossType = 'none';
lossVal = 1;
sweepVar = 'Eg';
sweepVal = linspace(0.4,2,100);
conc = 1;
emAngConc = 1;
qyFunc = @(E,Eg) 1;
TSun = 5780; % only used if 'sun'=='blackbody'
numE = 1000; % only used if 'sun'=='blackbody'
%%%%%%%%%%
%%%%%%%%%% Fundamental Constants
q = 1.602176565e-19; 
h = 6.62606957e-34; 
kT = 0.026; % technically kT/q, approx T=302K
kB = 1.3806488e-23;
c = 29979245800; % cm/s 
%%%%%%%%%%
procArgs(varargin);
% photonFlux has units mA/cm^2/eV (i.e. current density per unit energy)
if(strcmp(sun,'am1.5'))
    data = load('spectrum.mat'); % in ./Data
    photonFlux = data.photonFlux;
    E = data.E;
    clear data;
else 
    E = linspace(0.1, 5, numE);
    omegaSun = 6.85e-5; % SQ
    photonFlux = omegaSun * 2*1e3*(q^4/h^3/c^2)*E.^2.*exp(-E/(kB*TSun/q)); % extra factor of 1e3*q to get mA
end
% totCurrent = trapz(E, photonFlux) % 69 mA/cm^2, un-comment to verify
totPower = trapz(E, conc * E .* photonFlux); % 100.037 mW/cm^2 if 'am1.5'
fprintf('Total power in solar spectrum: %g  mW/cm^2 \n', totPower);

[YaLin]

I'm running this code, can I ask you some questions? I can't understand the formula inside

Answer 1

[Guru Mohanty]

Hi, I understand you are trying to plot Shockley Queisser. You can plot by these following steps.

clc;clear all;
Eg = linspace(0.4,2,100);
qy = @(E,Eg) floor(E/Eg);
d = ShockleyQueisser('Eg',Eg,'etaInt',0.9,'cm',qy);
figure;
plot(Eg, d.eff);

For more examples, you can refer here.