Controllable reductive method for synthesizing metal-containing particles
The invention is directed to a method for producing metal-containing particles, the method comprising subjecting an aqueous solution comprising a metal salt, E h , lowering reducing agent, pH adjusting agent, and water to conditions that maintain the E h value of the solution within the bounds of an E h -pH stability field corresponding to the composition of the metal-containing particles to be produced, and producing said metal-containing particles in said aqueous solution at a selected E h value within the bounds of said E h -pH stability field. The invention is also directed to the resulting metal-containing particles as well as devices in which they are incorporated.
1. A method for abiotically producing non-oxide metal chalcogenide particles, the method comprising subjecting an aqueous solution comprising: (i) a metal-containing component containing at least one chalcophilic metal; (ii) an adduct of cysteine or Se- or Te-analog thereof with a reduced sulfide, reduced selenide, or reduced telluride; (iii) pH adjusting agent; and (iv) water to reductive abiotic conditions, and maintaining the E h value of the solution by controlling the pH of said aqueous solution within the bounds of an E h -pH stability field corresponding to the composition of the non-oxide metal chalcogenide particles to be produced, and producing said non-oxide metal chalcogenide particles under said reductive abiotic conditions in said aqueous solution at a selected E h value within the bounds of said E h -pH stability field.
2. The method of claim 1 , wherein said E h is less than 200 mV and above −400 mV.
3. The method of claim 1 , wherein said chalcophilic metal is selected from the group consisting of cationic forms of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Hf, Ta, Cd, Mo, W, Ag, Pd, Pt, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi and combinations thereof.
4. The method of claim 1 , wherein said chalcophilic metal is selected from the group consisting of cationic forms of Cd, Cu, Fe, Ga, In, Sn, and Zn.
5. The method of claim 1 , wherein said non-oxide metal chalcogenide particles have a quantum dot composition selected from the group consisting of ZnX′, CdX′, CuX′, and SnX′ compositions, wherein X′ is selected from the group consisting of S, Se, Te, and combinations thereof.
6. The method of claim 1 , wherein said non-oxide metal chalcogenide particles have a composition of the formula:
Cu(In x Ga 1−x )X′ 2 (2)
wherein x is an integral or non-integral numerical value of or greater than 0 and less than or equal to 1, and X′ is selected from the group consisting of S, Se, Te, and combinations thereof.
7. The method of claim 1 , wherein said non-oxide metal chalcogenide particles have a composition of the formula:
M 3 SnX′ 4 (4)
wherein M represents at least one chalcophile metal other than Sn, and X′ is selected from the group consisting of S, Se, Te, and combinations thereof.
8. The method of claim 7 , wherein M is selected from the group consisting of Cu, Fe, Zn, Cd, and combinations thereof.
9. The method of claim 1 , wherein said aqueous solution further comprises a surface-active agent that interacts by coordinate bonds to surfaces of the non-oxide metal chalcogenide particles.
10. The method of claim 1 , wherein said aqueous solution is adjusted in pH to suitably lower the E h to be within the bounds of the E h -pH stability field corresponding to the composition of the non-oxide metal chalcogenide particles to be produced.
11. The method of claim 1 , wherein said non-oxide metal chalcogenide particles possess a size within a range of 2 nm to 100 nm.
12. The method of claim 1 , wherein said non-oxide metal chalcogenide particles possess a size of less than 50 nm.
13. The method of claim 1 , wherein said non-oxide metal chalcogenide particles possess a size of up to 20 nm.
14. The method of claim 1 , wherein the aqueous solution is maintained at a temperature of up to 70° C. during production of the non-oxide metal chalcogenide particles.