Glowing stereocomplex biopolymers are generating power: polylactide/carbon quantum dot hybrid nanofibers with high piezoresponse and multicolor luminescence
We report the design and fabrication of novel biodegradable hybrid polymeric nanofibers with the combined advantages of high shear piezoelectricity, multicolor photoluminescence and simultaneously improved heat resistance. The multifunctional flexible nanofibers, with uniform diameters and smooth surfaces, were fabricated through the electrospinning of poly(D-lactide) (PDLA)/poly(L-lactic acid) (PLLA)/carbon quantum dots (CQDs) with dichloromethane and alcohol as the mixed spinning solvent. The electrospinning at a high voltage enhanced the orientation and formation of stereocomplexed polylactide crystals, and at the same time remarkably suppressed the growth of homocrystallites in the ternary composite nanofibers. With the amplitude and/or frequency increase of stimulated dynamic loads, the electrical outputs of the stereocomplex PDLA/PLLA/CQD nanofibers increased, and the maximum open-circuit voltage and short-circuit current output density achieved were 74.2 V cm−3 and 4.9 μA cm−3, respectively. Also, the stereocomplexed nanofiber based nanogenerator, during continuous operation of electromechanical conversion, demonstrated good stability and durability as a power source to operate LEDs, and no electrical output decay was observed for more than 10 000 consecutive working cycles. Moreover, the electrospun hybridized nanofibers emitted different fluorescence colors under laser excitation at different wavelengths. The as-developed ecologically friendly bionanofibers may diversify niche applications in future transient electronics and implantable medical devices as self-powered bio-sensors, bio-piezoelectric nanogenerators, and so on.