Nanoparticles passivated with cationic metal-chalcogenide compound

1. A passivated nanoparticle colloid comprising:

a plurality of passivated nanoparticles, each of the passivated nanoparticles comprising a core nanoparticle and a cationic metal-chalcogenide compound (MCC) fixed on a surface of the core nanoparticle; and

a dispersion medium in which the passivated nanoparticles are dispersed,

wherein the cationic metal-chalcogenide compound (MCC) is selected from the group consisting of Zn 2 S 2 , Zn 2 Se 2 , Zn 2 Te 2 , Cu 2 S 2 , Cu 2 Se 2 , Cu 2 Te 2 , Mn 2 S 2 , Mn 2 Se 2 , Mn 2 Te 2 , Fe 2 S 2 , Fe 2 Se 2 , Fe 2 Te 2 , Co 2 S 2 , Co 2 Se 2 , Co 2 Te 2 , and mixtures thereof.

2. The passivated nanoparticle colloid of claim 1 , wherein the dispersion medium comprises ethanol amine, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), formamide, water, hydrazine, or hydrazine hydrate.

3. The passivated nanoparticle colloid of claim 1 , wherein the nanoparticle is a quantum dot, a metal nanocrystal (NC), a magnetic NC, an oxide NC, a nanowire, or a nanoplate.

4. The passivated nanoparticle colloid of claim 3 , wherein the quantum dot is selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe; GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; Si, Ge, SiC, SiGe, and combinations thereof.

5. The passivated nanoparticle colloid of claim 1 , wherein the cationic metal-chalcogenide compound (MCC) is directly fixed on the surface of the core nanoparticle.

6. A passivated nanoparticle colloid comprising:

a plurality of passivated nanoparticles, each of the passivated nanoparticles comprising a core nanoparticle and a cationic metal-chalcogenide compound (MCC) fixed on a surface of the core nanoparticle; and

a dispersion medium in which the passivated nanoparticles are dispersed,

wherein the passivated nanoparticle colloid does not contain hydrazine.

7. A method of preparing the passivated nanoparticle colloid according to claim 1 , the method comprising:

reacting a chalcogen element with NaBH 4 to form a sodium-chalcogenide compound;

reacting the sodium-chalcogenide compound with a metal perchlorate to form a metal-chalcogenide perchlorate; and

reacting the metal-chalcogenide perchlorate with ethanolamine to form the cationic metal-chalcogenide compound.

8. The method of claim 7 , wherein the metal perchlorate is selected from the group consisting of zinc perchlorate, tin perchlorate, indium perchlorate, antimony perchlorate, sodium perchlorate, silver perchlorate, iron perchlorate, potassium perchlorate, magnesium perchlorate, barium perchlorate, calcium perchlorate, cadmium perchlorate, aluminum perchlorate, manganese perchlorate, and platinum perchlorate.

9. A method of preparing the passivated nanoparticle colloid according to claim 1 , the method comprising, the method comprising:

providing a first dispersion, which is a dispersion of nanoparticles having a first organic ligand in a first organic solvent;

preparing a second solution, which is a solution of a cationic metal-chalcogenide compound in a second organic solvent;

mixing the first dispersion and the second solution to form a mixed solution; and

stirring the mixed solution thereby exchanging the first organic ligand of the nanoparticles with the cationic metal-chalcogenide compound.

10. The method of claim 9 , wherein the first organic ligand is selected from the group consisting of trioctylphosphine (TOP), trioctylphosphine oxide (TOPO), oleic acid, oleylamine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, hexylphosphonic acid (HPA), tetradecylphosphonic acid (TDPA), octylphosphonic acid (OPA), and combinations thereof.

11. The method of claim 9 , wherein the first organic solvent is cyclohexane, hexane, chloroform, toluene, octane, chlorobenzene, or a mixture thereof.

12. The method of claim 9 , wherein the mixed solution is phase separated into a first organic solvent layer from the first dispersion and a second organic solvent layer from the second solution.

13. The method of claim 9 , wherein the second organic solvent is ethanol amine, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), formamide, water, hydrazine, hydrazine hydrate, or a mixture thereof.

14. The passivated nanoparticle colloid of claim 1 , wherein the dispersion medium comprises ethanol amine, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), formamide, or water.