Study of Factors Affecting the Performance of CIGS Based Thin Film Solar Cells

This research aims to improve the CIGS (copper, indium-gallium, diselenide) thin-film photovoltaic cell using Silvaco-Atlas device simulator. Four important performance parameters extracted from the simulated data were its power conversion efficiency, open circuit voltage, fill factor and short circuit current density. In order to compare performance and validate the results with respect to the parameters acquired from the simulation, a CIGS-based solar cell that was experimentally constructed was utilised as a reference. The simulated cell was further optimised by tweaking the absorber material thickness, band gap and concentration of doping. The optimised CIGS cell achieved improved power conversion efficiency from 22.9% to 25%, fill factor from 81.47% to 83.65%, open circuit voltage from 702 mV to 840 mV and short circuit current density from 37.4 to 33.3 mA/ cm
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• The drop in current density is due to the rise in band gap from 1.1 to 1.2 eV or the change in ratio of Ga/(Ga+In) from 0.31 to 0.45. The overall performance boost in PCE, FF and Voc outweigh the drop seen in Jsc, The enhanced results of our optimised CIGS cell can be used as guideline for developing highly efficient device and the performance of the device can further be enhanced by using a hole and electron transport layers, by replacing the window layer, buffer layer, back contact layer and anti reflective coating with better performing materials or by using graded CIGS absorber layer with different band gaps.