The researchers have developed a method for fabricating a transparent conductive film simply by applying a carbon nanotube (CNT) dispersion liquid. This film features high conductivity comparable to that of metal particles and good durability, such as flexibility, elasticity, and resistance to high temperatures and humidity.

Comparison of conventional process and developed simple process that enables fabrication of high-performance CNT transparent conductive film

CNT transparent conductive films hold promise as a component of various electronic devices, from touch panels and solar cell electrodes to flexible and wearable devices expected to be expanded in the future. With existing coating technology, however, CNT dispersion and doping of CNTs must be performed separately, and it is also necessary to remove the insulating dispersant after film formation. This required multiple complex processes, and also limited the base materials that can be used for film formation.

The researchers have developed a technology for fabricating a highly conductive CNT film simply by applying CNT dispersion liquid to the base material by using a small quantity of polymeric acid that exhibits both CNT dispersant and dopant functions. The developed technology will significantly shorten the process time needed to fabricate high quality CNT transparent conductive films, and will also enable film formation on various base materials including curved surfaces and the inner surface of pipes. In addition, an environmentally friendly solvent such as water and ethanol can be selected, and uniform large-area films ranging from ultra-thin films with a thickness of several nm to thick films with a thickness of several tens of μm can be formed. As such, applications are expected in a wide range of fields.

Efforts will be made to develop specific applications for the developed CNT conductive film and the CNT dispersion liquid. In addition, mass production and quality assurance technologies will be established and broad collaboration with companies will be promoted to achieve practical application of the developed technology.