SiGe Thermoelectric Material Quantum Network Structure
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Solution Overview
Problem
Conventional thermoelectric materials fail to achieve significant improvements in the dimensionless performance index ZT, leading to suboptimal thermoelectric characteristics due to insufficient quantum effects from nanoparticles, where the particle size and interparticle distance do not effectively exhibit a quantum effect, resulting in low Seebeck coefficients and conductivity.
Innovation Solution
A thermoelectric material comprising Si and Ge with nanoparticles distributed in a quantum network structure, where the particle size is not greater than 5 nm and the interparticle distance is not greater than 2 nm, controlled by adjusting the concentration of a second material and the Si/Ge composition ratio, allowing for optimal quantum effects and enhanced thermoelectric performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanoparticles are formed in conventional thermoelectric materials, then the dimensionless performance index ZT is expected to improve, but the quantum effects are insufficient due to inadequate particle size and interparticle distance control
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size (not greater than 5 nm) and interparticle distance (not greater than 2 nm) of nanoparticles. This is achieved by adjusting the concentration of the second material and the Si/Ge composition ratio, which directly changes the physical parameters of the material structure to optimize quantum effects and thermoelectric performance.
Solution Approach 2:
The patent uses composite materials by creating a quantum network structure consisting of nanoparticles distributed in a matrix material. The composite structure combines the quantum confinement effects of nanoparticles with the bulk properties of the surrounding material, achieving enhanced thermoelectric characteristics that neither component could provide alone.
2Power
If the particle size is reduced to enhance quantum effects, then the Seebeck coefficient and conductivity improve, but the manufacturing precision required to achieve optimal particle size and distribution increases
Solution Approach 1:
The patent changes material parameters by controlling the concentration of the second material and the Si/Ge composition ratio, which indirectly controls the nanoparticle size and distribution. This approach allows optimization of quantum effects while using compositional parameters that are more easily controlled during manufacturing than direct particle size control.
3Reliability
If the quantum network structure is optimized to improve thermoelectric performance, then the dimensionless performance index ZT increases, but the complexity of controlling composition ratio and material concentration increases
Solution Approach 1:
The patent simplifies the control complexity by using two key compositional parameters (concentration of second material and Si/Ge composition ratio) to simultaneously control multiple structural features including particle size, interparticle distance, and phase distribution. This reduces the number of independent control variables needed to optimize the quantum network 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 approach results in improved thermoelectric characteristics by effectively controlling the quantum network structure, enhancing the Seebeck coefficient and conductivity, thereby increasing the dimensionless performance index ZT and achieving better thermoelectric conversion efficiency.
Implementation Method 1
Conventional thermoelectric materials fail to achieve significant improvements in the dimensionless performance index ZT, leading to suboptimal thermoelectric characteristics due to insufficient quantum effects from nanoparticles
Implementation Method 2
Seebeck coefficient S and thermal conductivity K can be controlled by lowering a dimension of carriers (free electrons or free holes) and increasing phonon scattering owing to quantum wells and quantum wires
Implementation Method 3
Seebeck coefficient S and thermal conductivity K can be controlled by lowering a dimension of carriers
Data Source
AI summary
Better thermoelectric characteristics of a thermoelectric material containing nanoparticles are achieved. The thermoelectric material contains a plurality of nanoparticles distributed in a mixture of a first material having a band gap and a second material different from the first material. The first material contains Si and Ge. A concentration of atoms of the second material and a composition ratio of Si to Ge satisfy relational expressions in expressions (1) and (2) below with c representing a concentration of atoms (unit of atomic %) of the second material in the thermoelectric material and r representing the composition ratio of Si to Ge:r≤0.62c−0.25 (1)r≥0.05c−0.06 (2).