热电功勋值 “ZT ”是一个衡量热电应用材料效率的无量纲量。其定义为:[latex]ZT = \frac{S^2 \sigma T}{\kappa}[/latex],其中 S 是热电系数。 塞贝克 系数,[latex]\sigma[/latex] 为电导率,T 为绝对温度,[latex]\kappa[/latex] 为热导率。ZT 值越高,表明热电材料的效率越高。.

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热电功勋值 “ZT ”是一个衡量热电应用材料效率的无量纲量。其定义为:[latex]ZT = \frac{S^2 \sigma T}{\kappa}[/latex],其中 S 是热电系数。 塞贝克 系数,[latex]\sigma[/latex] 为电导率,T 为绝对温度,[latex]\kappa[/latex] 为热导率。ZT 值越高,表明热电材料的效率越高。.
功率因数概括了热电能量转换材料必须具备的基本特性。分子 [latex]S^2 \sigma[/latex] 称为功率因数。需要高塞贝克系数(S)才能在给定温差下产生大电压,需要高导电率([latex]\sigma[/latex])才能将电阻(焦耳)加热损耗降至最低。分母热导率([latex]/kappa[/latex])必须尽可能低。低 [latex]\kappa[/latex] 有助于在器件上保持较大的温差,这对于发电 (塞贝克效应)和冷却(珀尔帖效应).
The primary challenge in thermoelectric material science is that these properties are often interdependent and conflicting. For instance, materials with high electrical conductivity (like metals) also tend to have high thermal conductivity due to the Wiedemann-Franz law. The quest for high ZT materials has led to advanced strategies like nanostructuring. By creating structures with features on the nanoscale, it is possible to scatter phonons (which carry heat) more effectively than electrons (which carry charge), thereby reducing [latex]kappa[/latex] without significantly harming [latex]sigma[/latex]. This ‘phonon-glass electron-crystal’ concept has led to significant improvements in ZT values over the last few decades.
热电品质因数(ZT)
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