High‐Performance Piezoelectric Nanogenerator and Self‐Charging Photo Power Cell Using Hexagonal Boron Nitride Nanoflakes and PVDF Composite

Two‐dimensional (2D) piezoelectric hexagonal boron nitride nanoflakes (h‐BN NFs) exhibit substantial potential for energy harvesting, electronics, and optoelectronics applications. Herein, a free‐standing PVDF/h‐BN NFs (Ph‐BN) composite film is synthesized for multi‐functional purposes. First and foremost, a piezoelectric nanogenerator (PENG) device is fabricated using free‐standing Ph‐BN composite films and the energy harvesting properties are performed. The nanogenerator, Ph‐BN‐7.5 PENG, exhibits the highest output voltage of 50 V and current of 250 nA with a maximum power of about 2 μW compared to other fabricated composite devices. Further, a photo power cell (PPC) is fabricated using PVA‐EY mixture dye as the photosensitive part or solar energy absorber, and Ph‐BN 7.5 film is utilized as the energy storage part. The PPC is self‐charged up to ≈1 V within 80 s under light illumination. The self‐charging mechanism for PPC is explained in detail. The Ph‐BN composite films demonstrate an innovative energy harvesting and storage approach, which can fulfill the energy prerequisite in the imminent future. A self‐chargeable photo‐power bank is developed using two‐dimensional (2D) hexagonal boron nitride nanoflakes (h‐BN NFs) (prepared via ball‐milling) as filler in the PVDF matrix is utilized as capacitor (energy storage) and ITO coated PET and PVA‐Eosin‐Y gel as photosensitive/solar energy absorber.