(CuO)
CuO is a p-type semiconductor with a monoclinic crystal structure and a relatively narrow band gap, enabling efficient light absorption in the visible range. Its electronic and optical properties make it suitable for applications in photovoltaics, photodetectors, and photocatalysis. CuO also exhibits notable catalytic activity in oxidation reactions and is widely used in gas sensing technologies due to its sensitivity to environmental gases. Thanks to its abundance, low toxicity, and ease of synthesis, CuO is an attractive material for large-scale and sustainable energy applications.