J0_fitter

This is a program written in python to determine the recombination current, aka J_0e at a surface of a solar cell from quasi steady state photoconductance measurements. The program currently only accepts inputs from a Sinton Instruements excel file, and calculates J_0e with a variety of published methods.

Installation

Check you have all the prerequsites installed and then just download the zipped file and run main.py file located in ./src/J0_fitter/ with python 3.5.

Prerequisites

You need to install python 3.5. Make sure you click the "add to path" option during installation for an easy time getting this running. To check python is installed enter

python

into the command prompt (windows users) or terminal (other os).

We now have to install other python packages. This is made quite easy by using pip. So to do this first

1. pip: Download GetPip.py. Then run the file with python. This can be done by cding into the downloaded directory and running:

   python get-pip.py
   

2. Install the following python packages:

   • numpy ^1,2
   • scipy ¹
   • matplotlib ¹
   • pyqt5
   • openpyxl

   These can be simply installed by typeing in:

   pip install package_name
   

   ¹ Note For windows users: Please download the indicated packages with here. Make sure to download the version for your python version (the standard python version is with 32 bit python 3.5, and so will be named with "win32" and "cp35" and in its filename). Once downloaded, cd into the directory and run:

```
pip install downloaded_package_name
```
<sup>2</sup> Note For windows users: Please make sure to install the numpy+MKL package and not just numpy.

3. Install 2 of my other packages (not on pip):

4. Semiconductor: download the latest wheel form here and run: pip install package name

5. PV_analyser here pip install package name

Methods

J0e/Current recombination prefactor determination

Here are a hosts of methods that are implemented in the program:

1. The original! Kane and Swanson method 1985
2. Adding Auger correction: King, Sinton, and Swanson 1990
3. An extension that accounts for injection dependent intrinsic carrier concentration: Blum et al 2013 and Kimmerle et al 2014
4. An extension that accounts for a constant Shockley Read Hall Lifetime: Kimmerle et al 2015
5. An extension that accounts a non-uniform carrier density: Kimmerle et al 2015

For the above methods which are modifications of the Kane and Swanson method the option exist to perform the measurement at:

1. A single excess carrier density value.
2. Each excess carrier density value, as suggested by B. Min et al

Determination of lifetime

The program also allows the used to:

1. Use the standard Sinton spread sheet caculations to determine the excess carrier density and lifetime
2. Take the raw measured parameters (PC coil voltage, and reference cell voltage), and caculate lifetime. The coil equipment calibration constants are extracted from the Sinton excel spread sheet.

For external calculations the the models that are taken from the semiconductor module. To emulate Sintons lifetime calculations please use the mobility model "Dannhauser-Krausse_1972".