P-type SnSe crystal capable of being used as thermoelectric refrigeration material and preparation method thereof

Patent metadata

Field	Value
Publication number	US-11629431-B2
Application number	US-202117551265-A
Country	US
Kind code	B2
Filing date	Dec 15, 2021
Priority date	Jun 4, 2021
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

The present disclosure relates to P-type SnSe crystal capable of being used as thermoelectric refrigeration material and a preparation method thereof. The material is a Na-doped and Pb-alloyed SnSe crystal. A molar ratio of Sn, Se, Pb and Na is (1-x-y):1:y:x, where 0.015≤x≤0.025 and 0.05≤y≤0.11. The P-type SnSe crystal provided by the present disclosure is capable of being used as the thermoelectric refrigeration material. A power factor PF of the P-type SnSe crystal at a room temperature is ≥70 μWcm−1K−2, and ZT at the room temperature is ≥1.2. A single-leg temperature difference measurement platform built on the basis of the obtained SnSe crystal may realize a refrigeration temperature difference of 17.6 K at a current of 2 A. The present disclosure adopts a modified directional solidification method and uses a continuous temperature region for slow cooling to grow a crystal to obtain the large-sized high-quality SnSe crystal.

First claim

What is claimed is:

1. A preparation method of P-type SnSe crystal capable of being used as thermoelectric refrigeration material, comprising:
step 1, mixing Sn, Se, Pb and Na according to a molar ratio of (1-x-y):1:y:x to obtain a mixture, where: 0.015≤x≤0.025 and 0.05≤y≤0.11;
step 2, performing a high-temperature melting synthesis reaction on the mixture; and
step 3, cooling and growing the composition subjected to the reaction in step 2 to obtain the P-type SnSe crystal, wherein the crystal is capable of being used as the thermoelectric refrigeration material.

2. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 1 , wherein step 2 specifically comprises:
placing the mixture in a quartz tube, and performing vacuumizing treatment, wherein a vacuum degree is less than or equal to 1×10 −3 Pa; and
vertically placing the quartz tube containing the mixture in a high-temperature furnace for the high-temperature melting synthesis reaction.

3. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 2 , wherein conditions of the high-temperature melting synthesis reaction comprise: first increasing a temperature of the high-temperature furnace to 1050-1100° C. at a rate of 50-100° C./h, and maintaining the temperature for 1000-1500 min for the high-temperature melting synthesis reaction.

4. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 2 , wherein the quartz tube is of a double-layer structure, and comprises an inner quartz tube configured to contain the mixture and an outer quartz tube, the inner quartz tube is a tapered-bottomed quartz tube with a tube wall thickness of not less than 1 mm, and the outer quartz tube is a flat-bottomed quartz tube with a tube wall thickness of not less than 1.5 mm.

5. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 3 , wherein the quartz tube is of a double-layer structure, and comprises an inner quartz tube configured to contain the mixture and an outer quartz tube, the inner quartz tube is a tapered-bottomed quartz tube with a tube wall thickness of not less than 1 mm, and the outer quartz tube is a flat-bottomed quartz tube with a tube wall thickness of not less than 1.5 mm.

6. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 4 , wherein an angle θ of a bottom taper of the inner quartz tube is 15°≤θ/2≤25°.

7. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 5 , wherein an angle θ of a bottom taper of the inner quartz tube is 15°≤θ/2≤25°.

8. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 4 , wherein a diameter difference between an inner wall diameter of the outer quartz tube and an outer wall diameter of the inner quartz tube is not less than 5 mm.

9. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 5 , wherein a diameter difference between an inner wall diameter of the outer quartz tube and an outer wall diameter of the inner quartz tube is not less than 5 mm.

10. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 4 , wherein a distance between a heating thermocouple of the high-temperature furnace and a bottom of the inner quartz tube is 9-11 cm.

11. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 5 , wherein a distance between a heating thermocouple of the high-temperature furnace and a bottom of the inner quartz tube is 9-11 cm.

12. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 4 , wherein an inner wall of the inner quartz tube is coated with a carbon layer for protection, and a thickness of the carbon layer is not less than 0.1 mm.

13. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 5 , wherein an inner wall of the inner quartz tube is coated with a carbon layer for protection, and a thickness of the carbon layer is not less than 0.1 mm.

14. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 1 , wherein step 3 specifically comprises:
decreasing the temperature of the high-temperature furnace to 650-700° C. at a rate of 0.5-1° C./h for crystal growth; and
then decreasing the temperature of the high-temperature furnace to 20-30° C. at a rate of 20-50° C./h to obtain the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material.

15. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 4 , wherein step 3 specifically comprises:
decreasing the temperature of the high-temperature furnace to 650-700° C. at a rate of 0.5-1° C./h for crystal growth; and
then decreasing the temperature of the high-temperature furnace to 20-30 C. at a rate of 20-50° C./h to obtain the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material.

16. The preparation method of the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material according to claim 5 , wherein step 3 specifically comprises:
decreasing the temperature of the high-temperature furnace to 650-700° C. at a rate of 0.5-1° C./h for crystal growth; and
then decreasing the temperature of the high-temperature furnace to 20-30° C. at a rate of 20-50° C./h to obtain the P-type SnSe crystal capable of being used as the thermoelectric refrigeration material.

Assignees

• Univ Beihang

Inventors

• Zhao Lidong
• Qin Bingchao
• Zhang Xiao

Classifications

• C30B9/04

  by cooling of the solution · CPC title

• C30B29/46 Primary

  Sulfur-, selenium- or tellurium-containing compounds · CPC title

• C30B23/066

  Heating of the material to be evaporated · CPC title

• H10N10/853 Primary

  comprising arsenic, antimony or bismuth (H10N10/852 takes precedence) · CPC title

• H10N10/01

  Manufacture or treatment · CPC title