Development of double-layer FF peptide microrod arrays for high performance piezoelectric nanogenerators.

Piezoelectric biomaterials have shown good energy conversion capability and promising future for biomedical applications. However, their performance is still limited by their relatively low piezoelectric constant, and increasing the power by connecting multiple devices is restricted by the challenge of synchronizing all individual devices. Herein, we develop double-layer FF peptide microrods arrays with independently controlled polarization in each layer. The resultant piezoelectric nanogenerator showed much enhanced performance because the synchronous deformation and the appropriate polarization directions of microrods in each individual layer enable the constructive contribution of voltage and current output from all microrods. The nanogenerator generated an open circuit voltage of 2.05 V in a serial connection mode, which doubles the output from a single-layer device. When two layers are connected in parallel and the polarization is in a head-to-head configuration, a twofold increase in the current output is also achieved. This work provides a new strategy to design integrated devices with much improved performance for wearable technology and therapeutic systems.