Widening UV–Vis absorption band by Cu doped ZnO and ZnO/CuO composite.

• ZnO, Cu doped ZnO, and CuO particles with 2D morphology was successfully synthetized by solvothermal method. • The doping process was successfully for 2 wt% Cu content. • For dopants from 6 to 50 wt%, there is CuO with rods shape. • For all Cu quantity incorporation presents a systematic widening in UV–Vis-NIR band absorption. ZnO, Cu doped ZnO, and CuO were synthesized by solvothermal method. Pure ZnO and CuO show two-dimensional (2D) particles with flake-like shape morphology and well-defined crystalline phases. The Cu incorporation slightly modifies the ZnO particle shape and size for low dopant. However, ZnO/CuO composite presents the co-existing morphologies with flake-like and small-rods shapes. The visible‐light absorption increases, directly proportional to the Cu content. However, ZnO/CuO composite shows wide ultraviolet–visible absorption between 200 and 1000 nm. The bandgap energy determined was 3.22 and 1.45 eV for ZnO and CuO, respectively. [ABSTRACT FROM AUTHOR]