A comprehensive numerical simulation analysis of back surface passivated CIGS solar cells for efficiency enhancement

Thin film solar cells are economical and simple to produce. This study seeks to comprehensively analyze ways to improve the efficiency and minimise the cost per watt of CIGS/SWCNT bulk heterojunction solar cells. The device performance is enhanced by lowering the defect density of single-walled carbon nanotubes (SWCNTs) and minimizing back surface recombination velocity through the back surface field mechanism. To maintain the realistic condition throughout the simulation authors, consider the series (Rs) and shunt (Rsh) resistances of 0.5 and 103 ohm cm2 respectively. The optoelectronic output parameters VOC, JSC, FF, and efficiency (eta) of the cells are extensively studied using the SCAPS-1D simulation tool with respect to variations in thickness, acceptor density, radiative recombination coefficient, parasitic resistance, work function, temperature, and defect density. The novel solar cell device structure Ni/SWCNT/CIGS/WS2/ZnO/Al exhibits a photoconversion efficiency of 27.73% followed by VOC of 0.80 V, FF of 80.38%, and JSC of 42.59 mA cm-2 at CIGS thickness of 400 nm. Mott Schottky Plot analysis was carried out at a frequency of 1 MHz to find the built-in potential (0.67 V) of the proposed solar cell. This simulation study could help manufacturing companies enhance the profitability of CIGS solar cell production.