Strained Zn‐Doped BaTiO 3 Nanorods for Efficient Light‐Responsive Mechanical Energy Harvesting via Piezo‐Phototronic Coupling

This work demonstrates enhanced mechanical micro energy harvesting from zinc (Zn)‐doped BaTiO 3 (BTO) nanorods through piezo‐phototronic effect. The doping of Zn in tetragonal BTO nanorods, synthesized by a low‐temperature hydrothermal process, imparts intentional lattice strain and facilitates bandgap modification (≈2.40 eV for 3 mol% doping) to exhibit both piezoelectric and semiconducting optoelectronic properties. Structure, morphology, and electrical characterizations using powder X‐ray diffraction, Raman spectroscopy, piezo force microscopy, and dielectric measurements, confirm the enhanced tetragonality, lattice strain, and piezoelectricity in Zn‐doped BTO. An efficient piezo‐photocurrent (90 nA and ≈1.2 times enhancement in light) is observed to produce a decent mechanical energy harvesting for the optimal Zn doping concentration (3 mol%) in BTO, producing an output power density of 522 nW cm −3 under warm white light source of 12 mW cm −2 at 7 N, 2 Hz. These findings highlight the potential of Zn‐doped BaTiO 3 as an environmentally friendly, multifunctional material for self‐powered devices and energy harvesters.