High-performance solution-based silicon heterojunction solar cells using carbon nanotube with polymeric acid doping

Carbon nanotube (CNT)/n-Si heterojunction solar cells were fabricated based on solution processes. CNT film with high transparency of 90% and low sheet resistance of similar to 115 Omega/sq was fabricated from commercially available CNT powder via dispersion-filtration process using poly(p-styrene-sulfonic acid) (PSS) as both dispersant and dopant. Heterojunction was then fabricated by attaching the CNT-PSS film onto an n-Si wafer. The CNT/n-Si solar cell showed an enhanced efficiency of 11.7% with the PSS-doping compared with the device without doping (7.7%). The device showed further improvements in efficiency to 14.1% with an antireflective coating layer of sulfonated polytetrafluoroethylene (Naflon) and stability to 1000 h in ambient air without additional protection. The solution-based strategies using polymeric acids for efficiency and stability enhancement will open new avenues for the low-cost CNT/Si heterojunction solar cells. (C) 2020 Elsevier Ltd. All rights reserved.