Room-temperature synthesis of (Ag,Cu)2S hollow spheres by cation exchange and their optical properties

► Hollow (Ag,Cu)2S microspheres with diameter of 700 nm to 1 μm were prepared with CuS hollow spheres as templates at room temperature. ► The shell was composed of nanoparticles. ► The absorption of hollow (Ag,Cu)2S spheres was strong in ultraviolet and infrared region but weak in visible region.