Stretchable Piezoelectric Membrane of Ferroelectric Charge‐Transfer Cocrystals for Efficient Energy Harvesting and Self‐Powered Wearable Sensors

Smart fiber actuators with self-sensing and intelligent actuation have inspired great efforts toward perceiving environmental changes and responding real-time movements, showing great promise in the man-machine interaction and the Internet of Things. Organic ferroelectric species present an enticing prospect in flexible mechanical actuators, yet are rarely developed in smart fiber actuators. Herein, we proposed an organic charge-transfer ferroelectric cocrystal composed of 7H-Dibenzo[c,g]carbazole and tetracyanoquinodimethane, which demonstrated a non-centrosymmetric alignment of Pc space group with a low coercive field of 500 V/cm. Furthermore, the scalable piezoelectric nanofibers with a piezoelectric coefficient of 0.6744 nm/V were achieved after undergoing the location self-assembly of ferroelectric cocrystal in polyvinylidene fluoride (PVDF) matrix during electrospinning process. Significantly, these prepared nanofibers were purposefully employed to form the flexible piezoelectric nanogenerator, yielding an instantaneous peak voltage output of 60 V under 200 N, and a pressure sensitivity of 0.3060 V/N. We foresee application possibilities in accurately detecting physiological signals, such as finger bending and respiration. This work opens up avenues to the wonderful optoelectronic application for the cost-effective ferroelectric cocrystal.