Piezoelectricity in a mixture of chiral 1D hybrid lead bromide and iodide systems

Abstract

Chiral organic-inorganic hybrid perovskites possess inherent structural asymmetry and lattice flexibility, enabling piezoelectric response suitable for energy harvesting and sensing technologies. Here, we introduced a new strategy for the development of a piezoelectric nanogenerator (PENG) constructed from a mixture of two chiral one dimensional perovskite derivatives, (R-MBA)PbBr₃ and (R-MBA)PbI₃ (MBA: methybenzylammonium). Individually, both halide systems exhibit piezoelectric behaviour, but when mixed, the piezoelectric output increases significantly. The highest performance is achieved for the optimized halide mixture: 75 wt% (R-MBA)PbBr₃ + 25 wt% (R-MBA)PbI₃. To improve flexibility and mechanical endurance, we incorporated the optimized halide mixture into a polycaprolactone (PCL) polymer matrix. The device with 15 wt% of the optimized halide mixture embedded in PCL demonstrates the highest peak-to-peak voltage of 40.8 V with a power density of 83.1 µW•cm⁻². The halide mixture-PCL composite significantly enhances the device performance, allowing higher impact force from 4 N at 6 Hz (without PCL) to 21 N at 8 Hz with an increase in the peak-topeak voltage, by 51%, compared to the neat mixture of hybrid halide salts without PCL. Finally, self-powered pressuresensors were fabricated by integrating multiple PENG devices and demonstrated for smart door mat applications. These findings show that physical mixing of chiral hybrid perovskites might be a useful approach to enhance piezoelectric performance.