Processes for preparing metal oxide semiconductor nanomaterials

A method for preparing a metal oxide semiconductor nanomaterial comprising CuO and ZnO in a modified tenorite crystalline structure wherein the metal oxide semiconductor nanomaterial consists of clusters of metal oxide quantum dots;

• wherein the metal oxide quantum dots consist of heterojunctions that are unions of n-type metal oxide nanoparticles and p-type metal oxide nanoparticles;
• wherein the heterojunctions exhibit an anisotropic conduction of electrons and unequal band gaps;
• and wherein the nanomaterial exhibits a chemical formula of Cu1-xO/ZnOx;
• wherein x is an atomic ratio of the ZnO in the metal oxide semiconductor nanomaterial, and further wherein there is an inhomogeneous distribution of the metal oxide in a surface region of the metal oxide semiconductor nanomaterial;
• the method comprising:
• a. providing a first aqueous solution comprising a soluble metal salt A and a soluble metal salt B wherein a metal of the soluble salt A and a metal of the soluble salt B are independently selected from a group consisting of zinc, copper, and combinations thereof;
• b. providing a second aqueous solution comprising at least one soluble anion source comprising sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, or combinations thereof;
• c. adding the second aqueous solution to the first aqueous solution to form an insoluble metal oxide semiconductor nanomaterial precursor, wherein the duration for forming the insoluble metal oxide semiconductor nanomaterial precursor is from 5 minutes up to 1 hour;
• and
• d. isolating the aqueous insoluble metal oxide semiconductor nanomaterial precursor;
• e. drying the aqueous insoluble metal oxide semiconductor nanomaterial precursor;
• and
• f. thermally decomposing the aqueous insoluble metal oxide semiconductor nanomaterial precursor at a temperature from 250° C. to about 350° C.,
• thereby forming the metal oxide semiconductor nanomaterial in the modified tenorite crystalline structure and the chemical formula of Cu1-xO/ZnOx.