Influence of WO₃-Based Antireflection Coatings on Current Density in Silicon Heterojunction Solar Cells

Antireflection coatings (ARCs) with an indium thin oxide (ITO) layer on silicon heterojunction solar cells (SHJ) have garnered significant attention, which is due to their potential for increasing current density (J_sc) and enhancing reliability. We propose an additional tungsten trioxide (WO₃) layer on the ITO/Si structure in this paper in order to raise the J_sc and demonstrate the influence on the SHJ solar cell. First, we simulate the J_sc characteristics for the proposed WO₃/ITO/Si structure in order to analyze J_sc depending on the thickness of WO₃ using an OPAL 2 simulator. As a result, the OPAL 2 simulation shows an increase in J_sc of 0.65 mA/cm² after the 19 nm WO₃ deposition on ITO with a doping concentration of 6.1 × 10²⁰/cm². We then fabricate the proposed samples and observe an improved efficiency of 0.5% with an increased J_sc of 0.75 mA/cm² when using a 20 nm thick WO₃ layer on the SHJ solar cell. The results indicate that the WO₃ layer can be a candidate to improve the efficiency of SHJ solar cells with a low fabrication cost.