Green Carbon Dots Illuminate Biogenic Nanohybrids toward Soft, Piezo/Photoactive, and Physically Transient Nanogenerators

Green electronics comprising degradable materials are ideal solutions for electronic wastes. Here, we report the construction of a soft, piezo/photoactive, and physically transient biogenic nanogenerator. A green luminescent, biogenic hybrid, carbon quantum dot (CQD)/cellulose nanocrystal (CNC)/polyhydroxybutyrate (PHB) nanofiber is manufactured with electrospinning technology. The synergy of CQD and CNC enables the enhancement of degradability of PHB. Simultaneously, the piezoelectric CNC makes a contribution to the piezoelectric response of the hybrid nanofiber. The appropriate inclusion of the CQD allows the creation of luminous, local stress concentration points that further enhance the piezoelectric response of the hybrid nanofiber. The output voltage and output current of the nanofibrous CQD/CNQ/PHB-based piezoelectric nanogenerator are 6.7 and 4.4 times higher than those of the state-of-the-art pristine PHB-based equivalent, respectively. This type of nanogenerator is also self-adaptive to changes in external mechanical stimuli. Moreover, the soft nanogenerator as a tactile sensor exhibits high reliability in the real-time dynamic sensing of athletic motions. Importantly, with a remarkable combination of piezoelectricity and photoluminescence, the biogenic nanogenerator array demonstrates the first application as a bimodal piezo/photo encryption alarm system. It shows great potential in the smart home and security field. We suppose that the multiple-responsive biogenic nanohybrids are very promising in green transient optoelectronics.