Optimization and Performance Enhancement of InP/CIGS/CuI Solar Cell Using Bandgap Grading

This paper presents a high performing Cu(In1 − xGax)Se2 (CIGS) based solar cell that uses naturally abundant and non-toxic InP (indium phosphide) as an electron transport layer and CuI (copper iodide) as a hole transport layer. These materials, InP and CuI, are better replacements for toxic material based solar cells. The proposed structure comprises a glass substrate/n-ZnO (Zinc oxide)/n-InP/p-CIGS/p-CuI/metal electrode. A graded CIGS layer (i.e. varying energy band gap and electron affinity) is used in this structure for a better harvesting of broad spectrum of solar energy. The proposed PV cell is optimized for different band gap grading of CIGS layer to enhance the performance of the cell. For further optimization of the proposed cell, thickness, doping concentration, and defect density of different layers are varied. After optimization, the proposed cell shows a maximum power conversion efficiency of 30.50