Optimized optical and electrical properties for silicon heterojunction solar cells with an indium tin oxide buffer layer

Abstract

Indium tin oxide (ITO) layers prepared with high power have significantly contributed to enhancing the crystal quality of films and the performance of silicon heterojunction solar cells. However, this process typically results in sputtering damage, which degrades photovoltaic efficiency. We have designed a thin ITO buffer layer prepared at low power and O₂ concentration, followed by an outer ITO layer prepared at high power and high O₂ concentration. Thus, the bilayer ITO film demonstrates superior optical and electrical properties, attributed to the optimized complex refractive index and resistivity achieved through synergistic control of power and oxygen levels, compared to monolayer ITO films. The leakage risk from the addition of an interface was suppress without compromising the open-circuit voltage. Consequently, the average efficiency improves to 25.36 % with a gain of 0.11 %, benefiting from optimized short-circuit current density and fill factor.