Selenium ink and methods of making and using same

1. A selenium ink, comprising:

a reaction product of:

selenium;

a traceless reducing agent;

and a liquid carrier;

wherein the selenium ink exhibits a selenide content of I to 50 wt %;

wherein the selenium ink is a stable dispersion and wherein the selenium ink contains less than 100 ppm hydrazine and less than 100 ppm hydrazinium complexed with selenium; and

wherein the reaction product is a counterion-selenide complex dispersed in the liquid carrier; wherein the counterion-selenide complex comprises selenium complexed with a counterion selected from an ammonium counterion and an amine counterion.

2. The selenium ink of claim 1 , wherein the traceless reducing agent is selected from reducing agents having a molecular weight of ≧35 and reducing agents having a molecular weight of <35; wherein the traceless reducing agent having a molecular weight <35 has a molecular formula with ≦1 nitrogen atom.

3. The selenium ink of claim 1 , wherein the traceless reducing agent is selected from the group consisting of formic acid; ammonium formate; ammonium oxalates; oxalic acid; formamides; lactates; carbon monoxide; hydrogen; isoascorbic acid; sulfur dioxide; acetaldehyde; aldehydes and combinations thereof.

4. The selenium ink of claim 1 , wherein the liquid carrier is a liquid amine having a formula NR 3 , wherein each R is independently selected from the group consisting of a H, a C 1-10 alkyl group, a C 6-10 aryl group and a C 1-10 alkylamino group.

5. The selenium ink of claim 1 , wherein the liquid carrier is selected from the group consisting of ethylene diamine, diethylenetriamine, n-butylamine, n-hexylamine, octylamine, 2-ethyl-1-hexylamine, 3-amino-1-propanol, pyridine, pyrrolidine, and tetramethylguanidine.

6. A method for depositing selenium on a substrate, comprising:

providing a substrate;

providing a selenium ink according to claim 1 ;

applying the selenium ink to the substrate forming a selenium precursor on the substrate;

treating the selenium precursor to remove the liquid carrier depositing selenium on the substrate; wherein the selenium deposited on the substrate is a mixture of Se 0 and Se 1- .

7. A method for preparing a Group 1a-1b-3a-6a material, comprising:

providing a substrate;

optionally, providing a Group 1a source comprising sodium;

providing a Group 1b source;

providing a Group 3a source;

optionally, providing a Group 6a sulfur source;

providing a Group 6a selenium source, wherein the Group 6a selenium source includes a selenium ink according to claim 1 ;

forming at least one Group 1a-1b-3a-6a precursor material on the substrate by optionally using the Group 1a source to apply sodium to the substrate, using the Group 1b source to apply a Group 1b material to the substrate, using the Group 3a source to apply a Group 3a material to the substrate, optionally using the Group 6a sulfur source to apply a sulfur material to the substrate and using the Group 6a selenium source to apply a selenium material to the substrate;

treating the precursor material to form a Group 1a-1b-3a-6a material having a formula Na L X m Y n S p Se q ;

wherein X is at least one Group 1b element selected from copper and silver; Y is at least one Group 3a element selected from aluminum, gallium and indium; 0≦L≦0.75; 0.25≦m≦1.5; n is 1; 0≦p<2.5; 0<q≦2.5; and, 1.8≦(p+q)≦2.5.

8. A method of preparing a selenium ink, comprising:

providing a selenium;

providing a traceless reducing agent;

providing a liquid carrier;

combining the selenium and the liquid carrier;

adding the traceless reducing agent to the combined selenium and liquid carrier to form mixture; and,

heating the mixture with agitation to convert the selenium to a (counterion)selenide complex forming the selenium ink;

wherein the counterion-selenide complex is stably dispersed in the liquid carrier; wherein the counterion-selenide complex comprises selenium complexed with a counterion selected from an ammonium counterion and an amine counterion;

wherein the selenium ink exhibits a selenide content of I to 50 wt %; and, wherein the selenium ink contains less than 100 ppm hydrazine and less than 100 ppm hydrazinium complexed with selenium.

9. The method of claim 8 , wherein 2 to 40 molar equivalents of the traceless reducing agent is provided relative to selenium.