In‐Situ Loading Bridgman Growth of Mg₃Bi_1.49Sb_0.5Te_0.01 Bulk Crystals for Thermoelectric Applications

Abstract

The single crystal growth of Mg3Bi2‐based thermoelectric materials is of great significance for their applications near room temperature. So far, it is still a big challenge to grow such bulk single crystals and attempts are primarily focused on the metal flux methods. For the first time, bulk single crystals of n‐type Mg3Bi1.49Sb0.5Te0.01 are directly grown by applying an In‐situ Loading Bridgman method. The as‐grown single crystal features an excellent carrier mobility of 220 cm2 V−1 s−1, which is among the best compared to other Mg3Bi2‐based bulk materials. Besides, this method is successfully developed to fast grow uniform polycrystalline materials with high thermoelectric and mechanic performance. As demonstrated by the single‐leg device, a large temperature difference of 10.5 K is achieved at the supplied electric current of 0.6 A, much superior to other room temperature state‐of‐the‐art thermoelectric materials. With the single crystalline and polycrystalline materials prepared reliably and conveniently, in‐depth investigations on the Mg3Bi2 thermoelectric system can be greatly benefited, which should as well significantly facilitate their practical applications at room temperature.

Solid-state cooling: thermoelectrics

“…16 The high performance in the mid-temperature range was discovered, after which promising performance of Mg 3 (Bi,Sb) 2 at near room temperature was significantly developed, making this system an efficient alternative for n-type Bi 2 Te 3− x Se x alloys with comparable performance. 5,14,17,93–104…”

“…10(a). Wang et al 14 successfully prepared single crystals of n-type Mg 3 (Bi,Sb) 2 by using an in-situ loading Bridgman method. Fig.…”

“…Recently, high-performance n-type Mg 3 (Bi,Sb) 2 semi-metals and p-type SnSe crystals with full-scale and highly integrated TE cooling devices were gradually developed. 5,13–18 However, there are still some problems to be solved before their large-scale commercialization. Moreover, recent research revealed that the traditional mid-temperature PbQ (Q = Te, Se, S) systems also possess extraordinary TE performance near room temperature with extremely high carrier mobility, 19 demonstrating great potential as new TE cooling materials, with practical devices to be further constructed.…”

Bridgman Growth of Mg2Sn1–xBix Single Crystals and Anisotropic Thermoelectric Properties

“…The above results raise obvious confusion on the singlecrystal growth of Mg 2 X-based (X = Si, Ge, Sn) materials. In this paper, the single-crystal growth was carefully reinvestigated and for the first time, a modified Bridgman method 27 ■ EXPERIMENTAL SECTION Crystal Growth of Mg 2 Sn 1−x Bi x (x = 0.01, 0.02, 0.03). All experimental manipulations for precursor synthesis were performed in a glove box with an oxygen level below 0.1 ppm or under vacuum.…”

“…Synthesis of the precursor for crystal growth was conducted using equipment and procedure proposed by previous work. 27 The raw materials were first incubated at 1123 K for 24 h to fully react and then quenched to room temperature to form ingots.…”