Method of fabricating thermoelectric materials using core-shell structured nano-particles, and thermoelectric materials fabricated by the same

1. A method of fabricating thermoelectric materials having dispersed nano-particles, comprising:

step 1) preparing core-shell structured metal oxide nano-particles having a thermoelectric pure bismuth metal element or a thermoelectric pure tellurium metal element coated on a surface of the metal oxide nano-particles;

step 2) adding and mixing the prepared core-shell structured metal oxide nano-particles of step 1, bismuth (Bi) salts, tellurium (Te) salts and a surfactant in a solvent to form a first mixture;

step 3) adding and dispersing a reducing agent in the first mixture of step 2 to form a second mixture;

step 4) heating the second mixture to form a heated second mixture; and

step 5) post-heat treating the heated second mixture at 250 to 350° C. for 1 hour to 5 hours in a hydrogen atmosphere, after the heating of step 4.

2. The method according to claim 1 , wherein the core of the core-shell structured metal oxide nano-particles in step 1) is partially coated with thermoelectric elements.

3. The method according to claim 1 , wherein the metal oxide is selected from the group consisting of aluminum oxide, magnesium oxide, titanium oxide, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide) and BaTiO 3 .

4. The method according to claim 1 , wherein the metal oxide nano-particles of step 1 are prepared in the form of a core-shell structure by the steps of:

step a) adding and dispersing nano-particles along with a surfactant in a solvent;

step b) adding and dissolving metal salts of thermoelectric elements to a solvent;

step c) mixing the solvent with the dispersed metal oxide nano-particles of step a), the solvent with the dissolved metal salts of the thermoelectric elements in step b), and a reducing agent to form a mixture; and

step d) heating the mixture of step c).

5. The method according to claim 4 , wherein the solvent of step a) and step b) is dioctylether or ethylene glycol.

6. The method according to claim 4 , wherein the metal salts of thermoelectric elements in step b) are selected from the group consisting of bismuth acetate, bismuth chloride and tellurium chloride.

7. The method according to claim 4 , wherein the reducing agent of step c) is 1,2-hexadecanediol, sodium borohydride (NaBH 4 ) or hydrazine (N 2 H 4 ).

8. The method according to claim 4 , wherein the heating of step d) is performed at a temperature range between 200 and 300° C. for 10 to 60 minutes.

9. The method according to claim 1 , wherein the bismuth salts of step 2 is bismuth acetate or bismuth chloride.

10. The method according to claim 1 , wherein the tellurium salts of step 2 is tellurium chloride.

11. The method according to claim 1 , wherein antimony chloride or selenium chloride is additionally added in the mixture of step 2.

12. The method according to claim 1 , wherein the surfactant of step 2 is oleylamine or trioctylphosphine.

13. The method according to claim 1 , wherein the solvent of step 2 is dioctylether or ethylene glycol.

14. The method according to claim 1 , wherein the reducing agent of step 3 is 1,2-hexadecanediol, sodium borohydride (NaBH 4 ) or hydrazine (N 2 H 4 ).

15. The method according to claim 1 , wherein the heating of step 4 is performed at a temperature range between 200 and 300° C. for 90 to 150 minutes.

16. The method according to claim 1 further comprising shaping the thermoelectric materials.