High-quality carbon nanotube films prepared by solvent-free gel coating and their application in dye-sensitized solar cells

Abstract

Carbon nanotubes (CNTs) have been attracting strong attention owning to their fascinating one-dimensional structure and unique mechanical, electrical and thermal properties. CNTs are promising in various important applications, but their application is severely impeded by their poor processibility, since they do not melt and usually have quite low solubility in solvents. The methods reported in literature for the dispersion of CNTs require an ultrasonication of CNTs under a high power or a chemical reaction, which can alter the physical properties and bring severe defects to CNTs. They are still far away from processing of CNTs in large scale, because only in a small amount of CNTs can be dispersed by these methods. Here, we will report a simple and efficient method to directly disperse CNTs in nonionic surfactants. CNTs and a nonionic surfactant form gels by mechanical grinding. The gels can be processed into CNT films by coating. The CNT films have good adhesion to the substrates and do not detach from the substrate after several weeks. We also demonstrate that the CNT films prepared by our method can be used as the counter electrode of highperformance dye-sensitized solar cells (DSCs). The photovoltaic efficiency is comparable to the devices using conventional noble platinum as the counter electrode. © 2010 SPIE.