Design of piezoelectric organic cage salts for energy harvesting

The utilization of organic piezoelectric materials for efficient mechanical-to-electrical energy conversion has gained considerable attention. However, the inherent tendency of organic crystals to crystallize in centrosymmetric space groups poses a significant obstacle in realizing their piezoelectric potential. To overcome this challenge, we present an effective synthetic strategy to design non-centrosymmetric crystal structures based on porous organic cages (POCs). By employing post-synthetic modification and anion regulation techniques, we successfully synthesized a family of non-centrosymmetric POCs and demonstrated their potential applications in piezoelectric energy harvesting. Among these materials, RCC3-SO4 exhibited excellent performance when incorporated into energy-harvesting devices, delivering an impressive open-circuit voltage of up to 5.4 V and a short-circuit current of up to 0.8 μA. These findings mark an important step forward in the field and pave the way for further advancements in organic piezoelectric materials and their practical implementation in energy-harvesting systems.