Nanostructured Electrospun Fibers with Self-Assembled Cyclo-L-Tryptophan-L-Tyrosine Dipeptide as Piezoelectric Materials and Optical Second Harmonic Generators

Abstract

The potential use of nanostructured dipeptide self-assemblies in materials science for energy harvesting devices is a highly sought-after area of research. Specifically, aromatic cyclo-dipeptides containing tryptophan have garnered attention due to their wide-bandgap semiconductor properties, high mechanical rigidity, photoluminescence, and nonlinear optical behavior. In this study, we present the development of a hybrid system comprising biopolymer electrospun fibers incorporated with the chiral cyclo-dipeptide L-Tryptophan-L-Tyrosine. The resulting nanofibers are wide-bandgap semiconductors (bandgap energy 4.0 eV) consisting of self-assembled nanotubes embedded within a polymer matrix, exhibiting intense blue photoluminescence. Moreover, the cyclo-dipeptide L-Tryptophan-L-Tyrosine incorporated into polycaprolactone nanofibers displays a strong effective second harmonic generation signal of 0.36 pm/V and shows notable piezoelectric properties with a high effective coefficient of 22 pCN−1, a piezoelectric voltage coefficient of geff=1.2 VmN−1 and a peak power density delivered by the nanofiber mat of 0.16μWcm−2. These hybrid systems hold great promise for applications in the field of nanoenergy harvesting and nanophotonics.

Electrospun Microstructured Biopolymer Fibers Containing the Self-Assembled Boc–Phe–Ile Dipeptide: Dielectric and Energy Harvesting Properties

“…The electrospinning technique has emerged as a powerful tool for producing fibers from a polymer solution doped with active molecules, namely dipeptides [16][17][18][19][20]. This involves applying a strong electric field between the tip of a syringe and a collector, resulting in the formation of fibers with diameters on the micro or nanometer scale [21,22].…”