Ultrasmooth, Large-Area, High-Uniformity, Conductive Transparent Single-Walled-Carbon-Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

A study was conducted to demonstrate methods for preparing single-walled nanotube (SWNT) films by ultrasonic spraying. The SWNTs had high transparency, electrical conductivity, and uniformity with low surface roughness on arbitrarily large substrates. Aqueous SWNT dispersions were prepared using a high-molecular-weight polymeric derivative of cellulose (sodium carboxymethyl cellulose) (CMC). It was demonstrated that combination of CMC-based dispersions and ultrasonic spraying permitted precise amounts of SWNTs to be reproducibly and uniformly dispensed over arbitrarily large areas. It was observed that interaction between CMC and SWNTs allowed dispersions to be prepared from highly crystalline LV SWNT ropes without significant sonication, which produced tube cutting and shortening. The findings of the study demonstrated that ultrasonic spraying of laser SWNTs from CMC-based solutions was suitable for large-area solution-based production of electrodes for photovoltaic and other optoelectronic applications.