Piezoelectric Vitamin‐Based Self‐Assemblies for Energy Generation

Structural diversity of biomolecules leads to various supramolecular organizations and asymmetric architectures of self-assemblies with significant piezoelectric response. However, the piezoelectricity of biomolecular self-assemblies has not been fully explored and the relationship between supramolecular structures and piezoelectricity remains poorly understood, which hinders the development of piezoelectric biomaterials. Herein, for the first time, the piezoelectricity of vitamin-based self-assemblies for power generation is systematically explored. X-ray diffraction studies revealed that vitamin molecules can self-assemble into different supramolecular structures, which exhibited tunable piezoelectric coefficients ranging from 3.8 to 42.8 pC N^-1 by density functional theory (DFT) calculations. Notably, vitamin B₇ D-biotin (D-BIO) self-assemblies exhibited superior piezoelectricity due to low crystal symmetry and high polarization of supramolecular arrangements. The D-BIO assemblies-based piezoelectric nanogenerator (PENG) produced output voltages of ≈0.8 V under a mechanical force of 47 N, showing high mechanical durability after 5400 pressing-releasing cycles and high stability of at least three months. The PENG-based wearable sensor successfully detected bending motions of human limbs. Furthermore, the PENG-based insole converted biomechanical energy into stable electrical energy upon foot movement, illuminating 12 light-emitting diodes (LEDs). This work fills knowledge gaps in piezoelectricity of vitamin-based self-assemblies, providing paradigms for realizing high-performance piezoelectric biomaterials through supramolecular engineering.