Enhancing Photoresponse Performance of Organic Self-Powered UV-Vis-NIR Photodetectors Using Cur- cuma Longa Extract

Recent advancements in optoelectronics highlight the potential of abundantly available plants as promising, eco-friendly semiconductor materials, offering tunable properties, flexible processing, and compatibility with low-cost, sustainable fabrication techniques. In this study, we obtained the extract of Curcuma Longa using the supercritical CO2 extraction method, which offers high efficiency while being environmentally friendly, solvent-free, and preserving heat-sensitive bioactive compounds. Thereafter, we employed Curcuma Longa extract (CLE) as interlayer an fabricate to Schottky photodetectors. Curcuma Longa thin films were characterized by X-ray diffraction, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The extract has shown a wide optical band gap of 2.94 eV , making it a significant candidate for optoelectronic applications. CLE-based device has shown excellent photoresponse performance against solar light and wave lengths ranging from 351 to 1600 nm. The ideality factor (n), determined using the thermionic emission (TE) model, increased from 3.28 (dark) to 5.19 under 100 mW /cm2 illumination, indicating the increasing influence of interface states and recombination mechanisms. Correspondingly, the Schottky barrier height (ΦB) decreased from 0.729 eV (dark) to 0.657 eV under illumination, suggesting barrier inhomogeneity and enhanced carrier transport under photoexcitation. The device exhibits high responsivity and external quantum efficiency (EQE) in the visible range (400–700 nm), with peak values at 500 nm (15.67 mA/W , 3.885% EQE) and 600 nm (13.87 mA/W , 2.866% EQE), while maintaining measurable but declining performance into the near-infrared (up to 1600 nm). Its broadband photodetection capability is further supported by low noise-equivalent power and high detectivity in the visible spectrum, though both degrade gradually beyond 800 nm, reflecting typical semiconductor behavior with optimal sensitivity at 500–600 nm. The findings highlighted the potential of a Curcuma Longa -based interlayer device for self-powered UV-Vis-NIR photodetector applications.