Organic Charge‐Transfer Dielectric Cocrystals for Flexible Triboelectric Nanogenerators and Wearable Application

ABSTRACT Organic triboelectric nanogenerators (OTENGs) with desired flexibility and fascinating electromechanical coupling have attracted continuous attention in material chemistry and wearable self‐powered application. Although the polyvinylidene fluoride (PVDF) and its derivatives have achieved great progresses in OTENGs, the unsatisfactory electronegativity induced by their low polar β ‐phase remains a huge challenge for a high‐performance electricity output. Herein, the self‐assembled 1,3,5‐Tris‐(4‐aminophenyl) benzene (TAPB)‐1,2,4,5‐tetracyanobenzene (TCNB) charge‐transfer (CT) cocrystals with a considerable dielectric constant of 10.2 were purposefully introduced into PVDF‐co‐hexafluoropropylene (PVDF‐HFP) matrix via a spin‐coating process to enhance its electronegativity. By sandwiching the composite film between Ag electrodes on the polyethylene terephthalate (PET) substrates, OTENGs with remarkable mechanical durability and reversible deformability were successfully prepared. The introduced TAPB‐TCNB cocrystal could significantly enhance the dielectric response and polar β ‐phase of PVDF‐HFP film, which is beneficial for a fivefold voltage output of 90 V compared to pure PVDF‐HFP OTENGs, and sensitivity of 2.926 V N ⁻¹ with the outstanding stability over 5000 cycles under the pressure of 50 N. Furthermore, the proposed devices hold strong potential for self‐powered wearable sensing applications, including human motion monitoring, gait analysis, and Morse‐code‐based communication.