Functionalized Graphene Reinforced Composite Nanofiber Membrane for Efficient Pyroelectric Energy Harvesting and Sensing.

The potential of using pyroelectric effect for thermal energy harvesting in advanced energy conversion systems has remained less explored. This work presents the design of a high-performance, flexible hybrid pyroelectric nanogenerator (PyNG), utilizing poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) electrode layered over a CdS-reduced graphene oxide (CdS-rGO) nanocomposite embedded in poly(vinylidene fluoride) (PVDF) electrospun nanofiber mats. It exhibits pyroelectric coefficient of ≈63 µC/(mK) at ambient temperature of 293 K, the highest reported among PVDF-nanofiber-based pyroelectric devices to date. It demonstrated excellent infrared-triggered thermal energy harvesting performance, generating 2.55 V/0.8 nA under cyclic heating and cooling with a ΔT of 42.5 K. The inclusion of CdS-rGO nanocomposite within the PVDF matrix and the flexible PEDOT:PSS electrodes significantly improved the performance, as further corroborated by density functional theory (DFT) simulations, revealing enhanced molecular-level interactions between PVDF and CdS-rGO. Its utility as a self-powered sensing is demonstrated by integrating in an N-95 face mask, enabling it to sense human respiration activity, offering high sensitivity to thermal fluctuation manifested from real-time respiration rate changes. The proposed PyNG holds great promise to be used as self-powered next-generation wearable sensors for personal health monitoring and the early detection of respiratory illnesses.