Detecting low-power ultraviolet (UV) light is crucial for practical applications. However, 1D ZnO/Ag based photodetectors (PDs) suffer from high expenses and care due to special operating conditions, posing challenges in capturing weak light signals and response time. To overcome these limitations, we integrate ZnO nanostructures with localized surface plasmon resonance of Ag nanoparticles via a surfactant-free hydrothermal-assisted polyol method, resulting in a notable bandgap reduction. SEM analysis revealed roughly spherical nanostructures for pristine ZnO and a porous structure in ZnO@Ag, around 1.4 µm in size with small agglomerates. XRD patterns showed reduced ZnO diffraction peak intensities in ZnO@Ag, confirming their core-like ZnO morphology. The fabricated ZnO@Ag heterojunction PD on an FTO substrate resulted in notable enhancement of PD performance. The ZnO@Ag heterojunction PD demonstrated a rapid 1.77 s response time, a 0.64 s recovery time and a specific detectivity of 11×107 cmHz1/2W−1, indicating its potential for low-cost and sustainable optoelectronics.