Hybrid Inorganic–Organic Heterojunction Solar Cell

Abstract

In this study, solar cells were fabricated by spin-coating polyaniline (PANI) base (EB) over an n-type Si substrate. The final heterojunction’s device structure was Al/n-type Si/EB/Au. The electrical properties of the resultant device were investigated by measuring the current density–voltage (J–V), capacitance–voltage (C–V), and impedance characteristics in the dark and under illumination. N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and tetrahydrofuran (THF) were used as solvents for EB. The effects of these solvents on the photovoltaic cell parameters were investigated, and the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and energy conversion efficiency (η) were determined. It was found that heterojunctions fabricated using EB dissolved in NMP, DMF, and THF produced Jsc of 10 mA/cm2, 5.123 mA/cm2, and 2.78 mA/cm2, respectively. Rollover and crossover phenomena in the J–V curves under illumination were explained based on the back-contact barrier and surface recombination of electrons at the back contact. The linearity of Mott–Schottky plots indicated the formation of a heterojunction between EB and n-type Si, and the slope of 1/C2 versus voltage changed under illumination. The high values of shunt resistance were decreased under illumination, indicating that the efficiency of this type of heterojunction solar cell was limited by shunt resistance and the narrow absorption range of the solar spectrum by EB.