Forming three-dimensional (3D) printed electronics

1. A method for forming three-dimensional (3D) printed electronics, the method comprising:

applying an unfused polymeric powder build material onto a fabrication bed;

selectively applying, via a first thermal inkjet printhead or a first piezoelectric inkjet printhead, a fusing agent on at least a portion of the unfused polymeric powder build material on the fabrication bed, wherein the fusing agent comprises a water- based dispersion including an infrared light absorbing colorant;

exposing the unfused polymeric powder build material on the fabrication bed to radiation, thereby fusing the portion of the unfused polymeric powder build material in contact with the fusing agent to form a 3D object layer on the fabrication bed; and

selectively applying, via a second thermal inkjet printhead or a second piezoelectric inkjet printhead, an aqueous formulation including an electronic agent selected from the group consisting of a semi-conductive material and an insulating material on at least a portion of the 3D object layer on the fabrication bed, thereby imparting semi-conductivity or an electrically insulating property on the at least the portion of the 3D object layer on the fabrication bed;

wherein the aqueous formulation including the electronic agent includes at least one of: water, a co-solvent, a pH adjuster, or a surfactant.

2. The method as defined in claim 1 , further comprising annealing the at least the portion of the 3D object layer.

3. The method as defined in claim 1 , wherein:

prior to the selectively applying of the aqueous formulation including the electronic agent, the method further includes selectively applying, via another thermal inkjet printhead or another piezoelectric inkjet printhead, a first aqueous formulation including a first electronic agent on an area of the at least the portion of the 3D object layer on the fabrication bed, thereby imparting a first electronic property to the area, wherein the first electronic agent is a conductive material;

the electronic agent is the insulating material and the aqueous formulation including the electronic agent is selectively applied on the first electronic agent, thereby imparting a second electronic property to the area; and

the first electronic property is conductivity and the second electronic property is the electrically insulating property.

4. The method as defined in claim 1 , further comprising at least partially embedding the at least the portion of the 3D object layer by:

applying additional unfused polymeric powder build material on the 3D object layer;

applying the fusing agent on at least a portion of the additional unfused polymeric powder build material; and

exposing the additional unfused polymeric powder build material to radiation, thereby fusing the at least the portion of the additional unfused polymeric powder build material.

5. The method as defined in claim 4 wherein the selectively applying of the fusing agent is accomplished by applying the fusing agent on the at least the portion of the additional unfused polymeric powder build material that does not cover the at least the portion of the 3D object layer having the electronic property.

6. The method as defined in claim 1 wherein:

prior to the selectively applying of the aqueous formulation including the electronic agent, the method further includes selectively applying a first aqueous formulation including a first electronic agent on a first area of the at least the portion of the 3D object layer on the fabrication bed, thereby imparting a first electronic property to the first area, wherein the first electronic agent is a conductive material;

the electronic agent is the insulating material and the aqueous formulation including the electronic agent is selectively applied on a second area of the at least the portion of the 3D object layer on the fabrication bed, thereby imparting a second electronic property to the second area; and

the first electronic property is conductivity and second electronic property is the electrically insulating property.

7. The method as defined in claim 1 wherein the unfused polymeric powder build material is a semi-crystalline thermoplastic material.

8. The method as defined in claim 1 wherein the unfused polymeric powder build material is a polyamide material selected from the group consisting of polyamide 11, polyamide 12, polyamide 6, polyamide 8, polyamide 9, polyamide 66, polyamide 612, polyamide 812, and polyamide 912.

9. The method as defined in claim 3 , wherein the conductive material includes a combination of carbon nanotubes, silver nanoparticles and a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate polymer.

10. The method as defined in claim 1 , wherein:

the electronic agent is the semi-conductive material; and

the semi-conductive material includes a combination of quantum dots and semi-conducting polymers.

11. The method as defined in claim 1 , wherein:

the electronic agent is the insulating material; and

the insulating material is selected from the group consisting of hexagonal boron nitride, a metal oxides, a metal nitride, a metal alkoxide, a metal chloride, silicate, polylactic acid, a fluoropolymer, polycarbonate, an acrylic polymer, polystyrene, benzocyclobutane, and a paraffin.

12. The method as defined in claim 3 , wherein the conductive material is selected from the group consisting of graphene and carbon nanotubes and is present in the first aqueous formulation in an amount ranging from about 0.1 wt % to about 3 wt %.

13. The method as defined in claim 6 , wherein the conductive material is selected from the group consisting of graphene and carbon nanotubes and is present in the first aqueous formulation in an amount ranging from about 0.1 wt % to about 3 wt %.