N-Type Mg3Bi2 Thermoelectric Material via Se Te Doping
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Solution Overview
Problem
Current thermoelectric conversion materials face challenges in achieving high performance, particularly in terms of thermoelectric figure of merit ZT and Seebeck coefficient S, with existing materials often being p-type or having low performance when the molar ratio of Se or Te is outside a specific range.
Innovation Solution
A novel thermoelectric conversion material with the chemical formula Mg3+mAB2-eE, where A represents Ca, Sr, Ba, or Yb, B represents Mn or Zn, D represents Sb or Bi, and E represents Se or Te, with specific values for m, a, b, and e, exhibiting a La2O3 crystal structure and being of n-type, which significantly improves performance by optimizing the molar ratio of Se or Te.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the molar ratio of Se or Te is outside a specific range, then the material can be synthesized, but the thermoelectric figure of merit ZT and Seebeck coefficient S are low
Solution Approach 1:
The patent optimizes the molar ratio of Se or Te to a specific range (0.001 ≤ e ≤ 0.06) to achieve high thermoelectric figure of merit ZT and negative Seebeck coefficient S. This parameter optimization transforms the material from low-performance to high-performance n-type thermoelectric material, resolving the contradiction between achieving synthesis and achieving high performance.
2Reliability
If existing thermoelectric materials are used, then they are available, but they are p-type or have low performance
Solution Approach 1:
The patent inverts the conventional p-type thermoelectric material by introducing specific dopants (Se or Te in controlled amounts) to achieve n-type behavior. This inversion transforms existing Mg3Bi2-xPnx or Mg3Sb2-xBix materials from p-type or low-performance to high-performance n-type materials, enabling broader applicability in thermoelectric devices.
3Reliability
If doping is increased to improve performance, then thermoelectric figure of merit ZT improves, but the crystal structure stability may be compromised
Solution Approach 1:
The patent applies local quality by introducing dopants (Se or Te) at specific local positions in the crystal structure with controlled concentrations (0.001 ≤ e ≤ 0.06). This localized doping approach optimizes thermoelectric performance while maintaining overall crystal structure stability, as the dopants are incorporated into specific lattice sites without disrupting the fundamental La2O3-type structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The material achieves high thermoelectric figure of merit ZT and negative Seebeck coefficient S within a specific temperature range, enhancing its n-type performance and overall efficiency.
Implementation Method 1
thermoelectric conversion material... achieves high thermoelectric figure of merit ZT and negative Seebeck coefficient S
Data Source
Figure 1
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Figure 2C
AI summary
The present invention provides a thermoelectric conversion material represented by the following chemical formula Mg3+mAaBbD2-eEe. The element A represents at least one selected from the group consisting of Ca, Sr, Ba and Yb. The element B represents at least one selected from the group consisting of Mn and Zn. The value of m is not less than -0.39 and not more than 0.42. The value of a is not less than 0 and not more than 0.12. The value of b is not less than 0 and not more than 0.48. The element D represents at least one selected from the group consisting of Sb and Bi. The element E represents at least one selected from the group consisting of Se and Te. The value of e is not less than 0.001 and not more than 0.06. The thermoelectric conversion material has a La2O3 crystalline structure. The thermoelectric conversion material is of n-type. The present invention provides a novel thermoelectric conversion material.