Piezoelectric Energy Harvesting and Body Motion Sensing of a Pair of 0D Chiral Hybrid Metal Halides

Chiral hybrid metal halides have received considerable attention in circularly polarized luminescence and spintronics due to their structural diversity, ease of synthesis, and chemical versatility. However, only a limited number of chiral metal halides have been utilized in piezoelectric energy harvesters and motion sensors. Furthermore, the exploration of 0D chiral piezoelectric materials is still in their early stage, offering substantial potential for further development. Herein, a pair of enantiomorphic hybrid metal halide piezoelectrics, R-(1-2-NEA)₂CdCl₄ and S-(1-2-NEA)₂CdCl₄ (1-2-NEA⁺=1-(2-naphthyl) ethylamine cation), were synthesized and structurally characterized. In addition, the devices comprising R-(1-2-NEA)₂CdCl₄/PDMS or S-(1-2-NEA)₂CdCl₄/PDMS (PDMS=polydimethylsiloxane) composite films were fabricated, and the energy harvesting performance of the devices with varying halide contents was explored. The results demonstrate that the devices comprising 10 wt % R-(1-2-NEA)₂CdCl₄/PDMS or S-(1-2-NEA)₂CdCl₄/PDMS exhibit significant energy harvesting capabilities, with an open-circuit voltage and a short-circuit current up to 8.24 V and 0.72 μA, respectively. Furthermore, the devices display exceptional mechanical durability after 4500 cycles and demonstrate excellent sensitivity in detecting various human body movements, such as walking, elbow bending, and finger bending. This study highlights the considerable potential of chiral hybrid metal halides for using in energy harvesting and wearable sensors.