High-sensitivity Ag@CuxO and Ag@CuxO:rGO core–shell heterostructure photodetectors with broad spectral range: Enhanced UV–IR response and superior long-term stability

Herein, Ag@CuxO and Ag@CuxO:rGO core–shell nanocomposite architectures were synthesized in the wet chemical method which was further analyzed by UV–Vis, XRD, XPS, SEM and TEM study. The as-prepared colloidal nanostructures were drop-casted onto n-type Si substrates to obtain n-Si/Ag@CuxO and n-Si/Ag@CuxO:rGO heterojunction photodetector devices. Current–voltage (I–V) characteristics under different light intensity and 365, 395, 590 and 850 nm wavelengths of illumination were measured. Under 365 nm illumination at −2 V bias, the responsivities of the n-Si/Ag@CuxO and n-Si/Ag@CuxO:rGO devices were determined to be 1.53 A/W and 4.26 A/W, respectively, indicating external quantum efficiencies exceeding 100 %. The better UV photosensitivity of n-Si/Ag@CuxO:rGO heterojunction is probably due to the improved electron transport capacity by rGO. Our findings demonstrate homojunction structure-based nanocomposites with very good photodetection performance, thus opening the door for next-generation optoelectronic device application. © 2026 Elsevier B.V.