Quasi-industrially produced large-area microscale graphene flakes assembled film with extremely high thermoelectric power factor

Abstract

The carbon-based nano materials, such as carbon nanotubes and graphene nanosheets, are emerged as feasible thermoelectric materials with advantages of low material cost and highly functionalizable surface. However, difficulty on large area manufacture and the relative low power factor limit their applications. Here, starting from graphene flakes solution, we obtained a large area free-standing graphene assembled film longer than 2.0 m based on a quasi-industrial film casting method. Moreover, we successfully realize an enhanced graphene film with a high electrical conductivity of 1400 S cm−1 and a resultant high thermoelectric power factor of 8.4 μW cm−1 K−2 at room temperature, as the highest value among graphene assembled thermoelectric film so far has been obtained. The high thermal power factor is achieved by ferric chloride (FeCl3) solution intercalation method, which efficiently enhances the hole density in graphene film. This large-size, quasi-industrially fabricated, flexible graphene assembled film has great applications in wasted heat harvesting as well as thermal and infrared sensors.