Oriented nanocrystalline silicon oxide contact enables excellent passivation for silicon solar cells

Abstract

Silicon oxide (SiOx) is often used to provide powerful passivation for the crystalline silicon (c-Si) solar cells; however, conventional SiOx passivated contacts are typically amorphous and defective, with low electrical conductivity. In this study, we introduce a sol-crystallization induction (SCI) method that enables the growth of compact, less defective, and vertically oriented SiOx (v-SiOx) passivated contacts on the c-Si surface. Compared to a-SiOx:H, v-SiOx demonstrates enhanced carrier concentration and vertical conductivity, forming an efficient electron-selective conduction contacts. By optimizing the v-SiOx nanocrystalline contact, we achieved an open-circuit voltage (VOC) of 746 mV and a short-circuit current density (JSC) of 41.54 mA cm−2 for the tunnel oxide passivated contact (TOPCon) solar cells, resulting in a power conversion efficiency (PCE) exceeding 26.01%. The promising SiOx passivation is expected to offer a significant support for the further development of high-efficiency c-Si solar cells, both in TOPCon and silicon heterojunction (SHJ) technologies.