Staggered Gap Enhancement Using a Homostructure Double Transport Layer for an Improved Efficiency in Cu2ZnSnS4 Solar Cell

Abstract

The staggered gap (type II) band alignment in photovoltaics offers exciting possibilities for improving charge separation and energy efficiency. However, achieving this configuration often requires complex fabrication processes, which can limit scalability and increase production costs. The focus of this paper is to seek ways of overcoming these limitations by considering a nanoparticle homostructure double transport layer under varying thicknesses of the second homostructure transport layers. The one-dimensional solar cell capacitance simulator (SCAP-1D) was used to investigate the optoelectronic properties of the setup, and the stopping and range of ions in matter (SRIM) code was used to investigate the functional characterization of spatial distribution of ions, vacancy generation, and likely elemental dynamics. The highest PCE of 21.43% was obtained with corresponding current density, fill factor, and open-circuit voltage of 38.75 mA/cm², 47.64, and 1.16 V. These results are unique, i.e., considering a kesterite active layer. Selected experimentation in this research work showed that the varying thicknesses of the second homostructure transport layer supported a near-perfect band alignment. Based on other parameters bordering on energy gap, J-V curve, C-V curve, DW-V curve, and EQE, all corroborated that the challenge of limited scalability had been solved. The functional characterization shows that organic transport layers will be successful in achieving the result reported in this work. Hence, commercial fabrication of the setup can be done with minimal error. It is recommended that production costs may be reduced by adopting the green-based substitutes as the buffer layer.