A Flexible Composite Mechanical Energy Harvester from a Ferroelectric Organoamino Phosphonium Salt

A new binary organic salt diphenyl diisopropylamino phosphonium hexaflurophosphate (DPDP⋅PF6) was shown to exhibit a good ferroelectric response and employed for mechanical energy harvesting application. The phosphonium salt crystallizes in the monoclinic noncentrosymmetric space group Cc and exhibits an H‐bonded 1D chain structure due to N−H⋅⋅⋅F interactions. Ferroelectric measurements on the single crystals of DPDP⋅PF6 gave a well‐saturated rectangular hysteresis loop with a remnant (Pr) polarization value of 6 μC cm−2. Further, composite devices based on polydimethylsiloxane (PDMS) films for various weight percentages (3, 5, 7, 10 and 20 wt %) of DPDP⋅PF6 were prepared and examined for power generation by using an impact test setup. A maximum output peak‐to‐peak voltage (VPP) of 8.5 V and an output peak‐to‐peak current (IPP) of 0.5 μA was obtained for the non‐poled composite film with 10 wt % of DPDP⋅PF6. These results show the efficacy of organic ferroelectric substances as potential micropower generators. Energy conversion: A non‐centrosymmetric binary organic salt [Ph2(iPrNH)2P]⋅PF6 has been synthesized and found to exhibit excellent thermal and phase stabilities. Ferroelectric measurements on this salt gave a remnant polarization value of 6 μC cm−2. In combination with polydimethylsiloxane a composite material was obtained and used as mechanical energy harvester.