Piezophototronic Properties in SnTiO 3 Nanomaterial for Self‐Powered Optoelectronics

The development of Pb‐free piezoelectric materials for self‐powered microelectronic systems has gained significant attention due to environmental concerns. Among the many, SnTiO 3 (STO) has also drawn considerable attention as a potential Pb‐free alternative. In this work, mechanical energy harvesting and piezophototronic properties are reported from a mixed nanocrystalline material with STO as one of the main phases, synthesized via a two‐step hydrothermal method. Microscopic and electrical characterizations reveal an effective coupling between mechanical strain, depicting high piezoelectric polarization ( d 33 ≈ 46 pm/V), commendable surface potential (∼70 mV), and enhanced photoexcited charge carriers under UV‐visible illumination contributed by STO. Under a periodic mechanical force of 15 N at 4 Hz, the STO nanomaterial based device generated a peak output voltage of ∼2.6 V and a current density of ∼45 nA/cm 2 without any external electrical poling, demonstrating stable and efficient energy harvesting performance. Furthermore, the material exhibits a pronounced piezophototronic effect under both UV and visible light illumination. The output power density increased from ∼1.1 to ∼1.4 µW/cm 2 (≈27% enhancement) under UV light and from ∼1.1 to ∼2.0 µW/cm 2 (≈ 82% enhancement) under visible light, highlighting strong modulation of charge transport through piezoelectric polarization. These results demonstrate that the presence of STO may provide a promising platform for self‐powered optoelectronic devices, light sensors, and sustainable energy harvesting systems, driven by efficient piezophototronic coupling.