Recent advancements in optoelectronics highlight the potential of abundantly available plants as promising semiconductor materials. In this study, we investigated the applicability of Lavandula angustifolia extract as an efficient and affordable self-powered UV-Vis-NIR photodetector with enhanced properties. Lavandula angustifolia extract was obtained using supercritical CO2 extraction method. It was characterized via ultraviolet–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The band gap was calculated as 3.50 eV, which proves its semiconductor behavior. Lavandula angustifolia extract based thin film was obtained to fabricate UV-Vis-NIR photodetector device. The device has shown excellent responsivity, detectivity, and external quantum efficiency to various wavelengths between 351 and 1600 nm. Under solar light, 0.436 A/W responsivity and 2.16 × 1010 Jones detectivity were recorded. The device has shown a responsivity of 25.146 mA/W and detectivity of 4.89 × 109 Jones at 1000 nm and 0 V bias voltage. The results obtained demonstrate the potential of a Lavandula angustifolia interlayered device for self-powered UV-Vis-NIR photodetector applications.