Development and application of LabVIEW program for analysis of solar cells current voltage diode parameters
Date
2019
Authors
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Publisher
University of Delaware
Abstract
Photovoltaics is the technology that generates DC (direct current) electricity from semiconducting materials under the influence of light energy(photons). Solar energy has proven that human beings can get substantial portion of their electric power without dissipating non-renewable energy forms such as fossil fuels, thermal/nuclear, and coal. ☐ The fundamental device used for developing PV systems is the solar cell. These solar cells comprise of semiconductor materials such as CuInGa(Se)2 (CIGS), Silicon (amorphous and polycrystalline), perovskites to name a few. Analysis of the current-voltage curve of the diode yields several parameters (called as diode parameters) such as series resistance, shunt resistance, ideality factor (also called diode quality factor), recombination current (J0), and a correction to the Fill Factor due to series and shunt resistances. From these parameters one can understand the performance of the solar cell and how the photons are converted to electrons and how efficient these solar cells work. These parameters also allow conducting a loss analysis to determine dominant loss mechanisms and ultimate performance after removing the impact of these losses. ☐ LabVIEW is a software developed by the National Instruments, that provides an environment for graphical computer programming. One can develop user-friendly programs not only for controlling for controlling instrumentation, operating control systems, data acquisition, but also as a tool for analyzing data. ☐ In this thesis I have developed a program nicknamed as DioMac (short form of Diode Analysis Machine) which is a user-intuitive tool for performing the diode analysis technique and generating the diode parameter results that get stored in a text file. This will help the scientists/researchers to analyze the samples quickly and obtain accurate results. I have applied this program to analyze several solar cell devices made at the IEC from different materials (Silicon (front heterojunction (FHJ), using PEDOT:PSS polymer, interdigitated back contact (IBC)), Laser Fire Contact solar cells, CuInGa(Se)2, and CuIn(Se)2 ). The current vs voltage data were measured at IEC under light and dark conditions. For the CIGS solar cell samples, the current-voltage characteristics curves are measured and observed at various temperatures. For Silicon FHJ and IBC solar cell samples, the diode parameter results are generated, compared and the relationship between each other has also been observed. For silicon solar cells using PEDOT:PSS polymer stored under Nitrogen, degradation of the performance in each week has been observed. The current-voltage data (J-V) analyzed for most of the solar cells studied in this thesis were measured at room temperature but DioMac is easily applied to J-V curves obtained at different temperatures or light intensities as well. I found that it is easily applied to well behaved solar cell devices described by single diode model but cannot be applied to those with non-ideal cells with blocking barriers or voltage dependent current collection.