熱電材料是一種能將熱能與電能相互轉換的材料,應用端包括能回收廢熱的發電機以及致冷元件的使用。大部分的熱電元件其溫度梯度與電場方向是相同的,本實驗中藉著非均勻的銀摻雜Bi0.4Sb1.6Te3熱壓試片在垂直方向的溫度梯度下建立水平方向的電場,此效應稱為橫向Seebeck效應,其分別熱流與電流方向的特性可以提供不同的元件應用方式。 實驗中確立了純Bi-Sb-Te的熱壓試片性質,且銀摻雜試片亦發現其熱電性質與未摻雜之熱電材料具有顯著差異。透過自行設計的橫向Seebeck量測裝置的實驗結果發現,非均勻的銀摻雜試片中確實具有橫向Seebeck電位差,且冷端之電壓差較熱端為大的非對稱電壓差。藉由實驗與模擬指出,其橫向Seebeck效應的來源應為銀摻雜區域與非銀摻雜區域的Seebeck係數差導致在同溫差下其產生電位差的不同所致。非對稱的橫向電壓差機制來源可能為帶電載子的濃度梯度,熱端載子相對更容易被驅動而致使其電壓差較小,藉由模擬中所導入之經驗參數jemp,將可說明此冷熱端非對稱電壓之結果。 本研究的實驗與模擬提供了以熱壓製程製備具橫向熱電效應材料之初步構想與模型,其橫向Seebeck係數在模擬值最高達120 μV/K。
Thermoelectric materials that can convert thermal energy to electric energy and vice versa have been applied in applications of waste-heat recovery and refrigeration. In most thermoelectric devices, the directions of temperature gradient and electric field are the same. In this research, a longitudinal temperature gradient introduces a lateral electric field, which is called transverse Seebeck effect, has been found in hot-pressed Bi0.4Sb1.6Te3 sample with non-uniform Ag doping. The property of uncoupling heat flow and electric flow directions may provide ideas of developing different device applications. The thermoelectric properties of both Ag-doped and non-doped Bi-Sb-Te samples have been determined experimentally. The transverse Seebeck effect has been found in non-uniform Ag doping sample with asymmetric transverse voltage in hot side and cold side by a self-designed transverse Seebeck measurement apparatus. The experimental and simulation results shows that transverse Seebeck effect should have been referred to different voltage drops between Ag-doped region and non-doped region. Asymmetric transverse voltage may be related to larger charged carrier flow at high temperature side, which has been expressed as an empirical term jemp in simulation. The experimental and simulation results have applied a preliminary model of transverse thermoelectric effect specimen fabrication. The transverse Seebeck coefficient has reached 120 μV/K in simulation.
為了持續優化網站功能與使用者體驗,本網站將Cookies分析技術用於網站營運、分析和個人化服務之目的。
若您繼續瀏覽本網站,即表示您同意本網站使用Cookies。