Improvement in the energy conversion efficiency for silicon heterojunction solar cells due to SiOx inserted with conducting filaments

Patterning an insulator to make electrical contact between the front electrode and the emitter is essential in solar cells, resulting in an increase in manufacturing cost. In this paper, conducting filaments (CFs) are applied to the silicon heterojunction (SHJ) solar cell with an SiOx/ITO structure for the first time. The self-assembled CFs in SiOx of 200 × 200 nm2 on the SHJ solar cell are directly observed via current-atomic force microscopy. Low series resistance of 2.2 Ω cm2 for the SHJ solar cell with SiOx is formed by the self-assembled CFs. In addition, high efficiency up to 20.24 % is achieved by the SHJ solar cell with CFs in SiOx without an additional patterning process. We thereby expect that the proposed technology will provide a tipping point from which a revolution in the solar cell industry can ensue. •Conducting filaments (CFs) were applied for the first time to make metal contact in solar cell without patterning process.•Low series resistance below 2.2 Ω∙cm2 was achieved via CFs formed in SiOx.•The feasibility of self-assembled CFs was demonstrated by improved conversion efficiency to 20.24 %.