Cuprous oxide (Cu₂O) is widely used as a red pigment in ceramics, glass, and paints, imparting a reddish-brown color, especially in antifouling marine paints to prevent biofouling on ship hulls. As a p-type semiconductor, it is employed in photovoltaic solar cells, light-emitting diodes (LEDs), photocathodes, image sensors, and light-detecting devices due to its photosensitive electrical properties. It serves as a conductive material in printed circuit boards and inks. Additionally, it acts as a catalyst in organic reactions, particularly oxidation processes, and is used in the synthesis of other copper-based chemicals. Its biocidal properties make it suitable for antimicrobial coatings in medical and industrial environments.