Reduced graphene oxide filled cellulose films for flexible temperature sensor application

[Display omitted] •Eco-friendly material.•Cellulose and reduced graphene oxide composite films.•Temperature sensing material.•Effect of reduction temperature of GO on sensing properties. Graphene based polymer nanocomposites are widely used in flexible electronics and in sensing technology. However, ecofriendly materials with utmost performances are still under investigation. Here we report a simple, flexible, partially transparent and efficient temperature sensor fabricated from composite film of reduced graphene oxide (rGO) and cellulose. The rGO nanosheets are obtained by partial reduction of graphene oxide through low-temperature multi-step annealing. The relative capacitance of the sensor changes as a function of temperature for all thermally reduced rGO filled composites. Upon temperature stimulation, charges form at the rGO–cellulose interface. This mechanism allows the composite films to act as high performance capacitive sensors capable of detecting temperature variations. The functional properties of the reusable, ecofriendly and inexpensive rGO–cellulose device, allow for potential temperature sensor application, which is one among the best ever reported.