Gold nanoparticle-cellulose/PDMS nanocomposite: a flexible dielectric material for harvesting mechanical energy

Cellulose is an abundant natural piezoelectric polymer and is also a renewable resource of significant importance. Here in this work we realize an enhanced piezoelectric response with cellulose in a polydimethylsiloxane (PDMS) matrix by forming a nanocomposite with the incorporation of gold nanoparticles (Au NPs). In the Au NP-cellulose/PDMS nanocomposite an enhancement in the dielectric constant is recorded due to the presence of cellulose alone and a reduction of dielectric loss is found owing to the presence of Au NPs. This opens the possibility of realizing a nanodielectric material from the nanocomposite under current study. This also indicates the significant potential of the nanocomposite towards energy conversion applications. Subsequently, a mechanical energy harvesting device was fabricated using the Au NP-cellulose/PDMS nanocomposite, which is named as a piezoelectric nanogenerator (PNG). The PNG delivered an enhanced open circuit voltage of ∼6 V, short circuit current of ∼700 nA and a peak power density of 8.34 mW m^-2 without performing any electrical poling steps. The PNG could charge a 10 μF capacitor to 6.3 V in 677 s and could light two commercial blue light emitting diodes (LEDs) simultaneously. The PNG exhibited a good energy conversion efficiency of 1.8%. A touch sensor application of the PNG is also shown.