永續計畫資料庫

In all internal combustion engines (ICE), less than 40% of the energy released from the fuel can be utilized to deliver WORK, and more than 60% of the energy is discharged as WASTE HEAT. Thermoelectric (TE) devices are the best solution to harvest this WASTE HEAT and to extract more gainful WORK from the fuel. It has been demonstrated by FORD and BMW that up to 10% extra mileage can be obtained using a TE device installed on the exhaust pipeline. However, due to the high cost of the TE materials, TE devices are implemented only in niche applications such as radioisotope generators (RTG) in space and for the cooling of high sensitivity detectors.           

In this work, we propose to focus on the development of SnS as a material for developing low-cost and high-efficiency TE devices, which can be widely used in industrial civic applications as an energy-saving solution. Our previous works have preliminarily demonstrated exciting results of SnS as a p-type TE material. We will proceed to develop a TE device based on SnS, including n-type doping for SnS, thin film deposition, and fundamental understanding and optimization resulting in a series of SnS-based TE applications.          

Our team has more than 10 years of experience in thermoelectric research and has achieved a high record figure-of-merit (ZT ~ 2.7) for GeSbTe and ZT > 3.0 for W-doped GeSbTe. However, the application of such TE devices has been hindered by the high cost of the TE materials. Following our experiences of working with SnSe, we proceed to study SnS, an earth-abundant and low-cost material for TE applications. A preliminary result shows ZT > 3.0 near room temperature, which is highly desirable for both power generation and cooling. Therefore, we decided to focus on SnS as both p- and n-type materials for future TE applications. A three-year project would allow us to deliver a prototype SnS-based TE device capable of near-room temperature operation. Large-scale pilot production will be initiated after the first three-year research phase. 

研發硫化亞錫作為下一世代熱電應用 一般的內燃機將「燃料」使用之後只將低於40%的能量轉換成「功」，其餘高於60%的能量成為「廢熱」排出，如果能將部分上述廢熱回收再利用，將對能源與氣候變遷有重大貢獻。而「熱電元件」可以將熱轉換成電，是回收廢熱的最佳選擇。過去福特汽車與BMW都曾實驗將熱電元件裝在汽車排氣管上，可以提升高達10%的里程數，這在能源議題上是相當可觀的。但是，因為熱電元件造價過高，該方案並沒獲得廣泛應用。          

本團隊累積過去熱電研究經驗，發現硫化亞錫（SnS）可以成為高效率熱電材料。在適度摻雜之後，SnS的p型半導體性質良好，加上其在地表含量豐富，可成為經濟價廉的熱電材料。本計畫將集中在SnS的研究，一方面優化當前初步成果，同時開發n型SnS半導體，並且在晶體與薄膜成長上並行，同時進行元件製作，以提供SnS熱電元件的原型，進而將本構想推廣至工業與一般民生用途上。          

本計畫團隊過去在GeSbTe研究上已經達到ZT ~ 2.7 的成果，甚至在W-doped GeSbTe方面已經達到ZT ~ 3.0的目標，但是都因材料含Ge、Te等稀有元素，受到材料成本過高限制而無法廣泛應用。過去一年來我們終於發現SnS可成為高效熱電材料，開啟了熱電廣泛應用的契機。初步結果看來，SnS可在接近室溫下達到ZT ~ 3.0的地步，可以成為熱電發電及冷卻的新方向。所以本團隊決定調整方向，在未來三年全力投入SnS熱電材料與元件的開發。盼能掌握先機，在永續能源上做出重大貢獻。