Investigation of annealing effects on physical properties of chemically prepared copper oxide thin films

•CuO thin films prepared successfully by chemical bath deposition.•Annealing effects observed and measured for muffle furnace.•Excellent optical properties achieved for prepared thin films.•p-type films with excellent properties for Perovskite devices.•Equally applicable in n-i-p Perovskite solar cells and p-n junctions. Copper Oxide (CuO) thin films, a candidate for PSC and p-n junction SCs, were deposited on glass substrates by chemical bath deposition (CBD) and effects of annealing at 300, 350, 400, 450, and 500 °C for 1 h in a muffle furnace on different physical properties were studied. XRD spectra matched well with monoclinic nature of CuO. XRD results revealed that with increasing annealing temperature, crystallite size increased. Raman spectroscopy confirmed development of CuO phase. UV–vis spectroscopy showed excellent photo absorption in the visible region of incident sun light and absorption coefficient remained high. Optical bandgap energy decreased in the range of 1.45 to 1.52 eV with increasing annealing temperatures. Conductivity type observed by thermoelectric/hot probe confirmed the p-type conductivity. The obtained results suggest that CuO thin films with excellent optical properties and p-type nature could be reliably companioned with n-type layer in both n-i-p PSC and p-n junction solar cell structures.