"Self‐Matched" Tribo/Piezoelectric Nanogenerators Using Vapor‐Induced Phase‐Separated Poly(vinylidene fluoride) and Recombinant Spider Silk. Issue 10 (27th January 2020) - Huang, Tao
Abstract: Flexible biocompatible mechanical energy harvesters are drawing increasing interest because of their high energy‐harvesting efficiency for powering wearable/implantable devices. Here, a type of "self‐matched" tribo‐piezoelectric nanogenerators composed of genetically engineered recombinant spider silk protein and piezoelectric poly(vinylidene fluoride) (PVDF)‐decorated poly(ethylene terephthalate) (PET) layers is reported. The PET layer serves as a shared structure and electrification layer for both piezoelectric and triboelectric nanogenerators. Importantly, the PVDF generates a strong piezo‐potential that modifies the surface potential of the PET layer to match the electron‐transfer direction of the spider silk during triboelectrification. A "vapor‐induced phase‐separation" process is developed to enhance the piezoelectric performance in a facile and "green" roll‐to‐roll manufacturing fashion. The devices show exceptional output performance and energy transformation efficiency among currently existing energy harvesters of similar sizes and exhibit the potential for large‐scale fabrication and various implantable/wearable applications. Abstract : A self‐matched tribo/piezo‐nanogenerator (TPNG), composed of genetically engineered recombinant spider silk protein and a piezoelectric poly(vinylidene fluoride)‐decorated poly(ethylene terephthalate) layer, generates a greatly enhanced energy output. Since the structural and electron potential match, the power density from the TPNG can reach 4016 mW m −2 and energy transform efficiency is 50.9%, suggesting potential applications in implantable and wearable electronics.