Boosting the dielectric and electrical performance of perovskite materials by collaborative augmentation with reduced graphene oxide nanosheets for cutting-edge storage solutions

Abstract

This investigation delved into the dielectric properties of methylammonium lead iodide (MAPbI₃) nanoparticles and MAPbI₃@rGO nanocomposites, using a co-precipitation approach to synthesize a reduced graphene oxide (rGO)-doped MAPbI₃ nanocomposite with varying concentrations. The study adjusted the temperature, doping concentrations, and frequency ranges to fully examine the dielectric characteristics, focusing on temperature range 25–60 °C, doping concentrations 0.5 wt%, 1 wt%, 5 wt%, and 7 wt%, and frequency range 10 Hz–4 MHz. The dielectric response analysis shows that the relative permittivity of MAPbI₃ (∼870@10 Hz) is significantly enhanced (∼5.8 × 10⁵@10 Hz, ∼500 times at ambient temperature) in the presence of rGO. The significant enhancement in dielectric permittivity in the MAPbI₃@rGO composites is due to numerous interfaces, ion migration, polar group reorientation, and nanocapacitor formation, which increases with temperature, thereby enhancing the relative permittivity. Nevertheless, at 60 °C and 10 Hz, the relative permittivity value for MAPbI₃@rGO composites reaches nearly 2.8 × 10⁶ (2000 times), the highest reported MAPbI₃ composite to date. The composite material exhibited remarkable potential as a supercapacitor dielectric material, as evidenced by dielectric constant increases of up to 10⁵ orders of magnitude following rGO injection at room temperature. Moreover, the AC conductivity at room temperature for MAPbI₃@rGO (7.9 × 10⁻³ s m⁻¹) is higher than that of pristine MAPbI₃ (1.01 × 10⁻³ s m⁻¹), possibly due to more charge conduction from the valence band to the conduction band. The conductivity is also increased as a function of temperatures for all composites (σ_max = 15.3 × 10⁻³ s m⁻¹@60 °C) due to the decrement of electronic resistance. The dielectric loss value exhibits a downward trend (for MAPbI₃ ∼18 and MAPbI₃@rGO ∼2.3, decreased by ∼6 times), and the repair of the sp² network in the graphene sheet is approved by the higher AC conductivity in MAPbI₃@rGO NCs relative to MAPbI₃ NPs. Furthermore, MAPbI₃ augmented with rGO is predicted to be a promising material for energy storage capacitive devices in the electronic industry due to its superior NTCR behaviour.