High dielectric CsPbBr3/rGO/polyimide composite prepared via in-situ conversion of fillers

High dielectric (high-k) polymer matrix composites (PMCs) have attracted much attention owing to their moderate dielectric property, good thermal stability, and excellent mechanical flexibility, as well as facile processability, light weight, and low cost. Herein, we report an in-situ synthesis strategy to fabricate high-performance high-k PMCs. A novel perovskite CsPbBr3/rGO/polyimide composite is fabricated by in-situ polymerization of poly(amic acid) (PAA) followed by thermal imidization, in-situ chemical reduction of graphene oxide (GO), and in-situ crystallization of CsPbBr3 nanoparticles. The fillers are uniformly dispersed in the polyimide (PI) matrix due to the multiple in-situ conversion processes, which form numerous micro-capacitors to enhance the dielectric permittivity. Attributing to the synergetic effect between rGO and CsPbBr3 nanocrystals, the CsPbBr3/rGO/PI composite showed a high dielectric permittivity up to 213, a high energy storage density of up to 5.20 J cm−3, and a dielectric loss less than 0.35. Besides, the thermal stability of the composites is enhanced (5% weight loss temperature (T5%) > 523 °C), and the mechanical strength is well retained under a relatively low filling amount of fillers (10 wt% CsPbBr3). Therefore, the as-fabricated CsPbBr3/rGO/PI composites would be promising for applications in energy storage polymer thin-film capacitors, and this research also opens a new avenue to fabricate high-k PMCs with good comprehensive properties.