Dielectric constant enhancement of poly 4-vinylphenol (PVPh) via graphene flakes incorporation through electrospray atomization for energy storage

We report on the fabrication of hybrid composite poly 4-vinlyphenol (PVPh)/graphene thin film via cost-effective electrospray atomization deposition technique. Thin films fabricated through manipulating deposition technique in two different ways which are blending and layer by layer (LBL). For investigation of PVPh/graphene hybrid composite dielectric behavior in comparison to PVPh; three asymmetric MIS thin film capacitors were fabricated, where dielectric thin films (i) PVPh and (ii & iii) hybrid composite thin films PVPh/graphene (blended and LBL) were sandwiched between electrodes i.e. indium tin oxide (ITO) and p-type semiconductor poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The dielectric properties of the thin films were characterized for frequencies 1 to 100 kHz while utilizing the MIS thin film capacitors. The capacitance obtained at 1 kHz frequency for PVPh/graphene (LBL) dielectric layer at the voltage range +/- 10 volts was 8.5 mF cm(-2) while for blended PVPh/graphene thin film the capacitance at the voltage range +/- 3 volts was 0.40 mu F cm(-2) and for pristine PVPh as dielectric layer the capacitance at voltage range +/- 1 volts was 1.45 mu F cm(-2). Similarly, even at higher frequencies up to 100 kHz, the PVPh/graphene (LBL) showed stable behavior. Thus, the composite PVPh/graphene (LBL) thin film has a better dielectric nature compared to the composite PVPh/graphene (blended) thin film, even at higher frequencies with larger operational voltage window. This distinguishing nature of the composite PVP/graphene (LBL) is attributed to increase in dielectric constant due to graphene flakes in between PVPh. For the thin films LBL and blended PVPh/graphene, the calculated dielectric constant at 10 kHz is 6.7 and 0.023 while at 100 kHz it is 2 and 0.0167, respectively.

Automated summary

We fabricated hybrid composite poly 4-vinlyphenol (PVPh)/graphene thin film using electrospray atomization deposition technique. The dielectric behavior of the PVPh/graphene hybrid composite was investigated and compared to PVPh. The results showed that the PVPh/graphene thin film exhibited better dielectric properties, especially at higher frequencies.