Small-bundle single-wall carbon nanotubes for high-efficiency silicon heterojunction solar cells

Abstract

Single-wall carbon nanotubes (SWCNTs) are a promising material for constructing high-performance photovoltaic conversion devices due to their excellent optical and electrical properties. Here we report a high-quality, small-bundle SWCNT film for the fabrication of high-efficiency silicon heterojunction solar cells. The SWCNT film synthesized by floating catalyst chemical vapor deposition has a low sheet resistance of 180 Ω sq−1 at 90% transmittance, which is more than two times lower than that of previously reported pristine SWCNTs used for SWCNT/Si heterojunction solar cells. Effects of the thickness of SWCNT film and device active area on the performance of the cells were investigated, and high power conversion efficiencies of 14.2% and 11.8% were achieved for devices with active areas of 2.3 mm2 and 9.0 mm2, respectively. This excellent performance is ascribed to the good optical and electrical properties of the SWCNT films originating from their high quality and small-bundle characteristics.