碲化鉍系化合物在低溫環境具有極佳的熱電性質，是目前商用元件中最被廣泛應用的材料系統。而傳統塊材型熱電元件是由熱電材料與鍍製好電極的陶瓷基板相接組成，受到剛性基板的限制，不利於應用在不規則熱源上。相反地，在軟性基板上使用印刷技術製備的熱電厚膜模組具有可撓性，能有效從不規則熱源的表面收集熱能，適合用於低溫差的環境中製造低功率(μW-mW)的發電裝置。在本研究中，我們通過網版印刷製備了數十微米的p型(Bi-Sb-Te)和n型(Bi-Te-Se)熱電厚膜，在優化的熱壓製程處理後，p型及n型熱電厚膜的功率因數分別可達1.43 mW/K2m及0.84 mW/K2m。以同樣的熱處理條件，我們利用網印技術與熱壓製程在聚酰亞胺基板上製備由3對p/n接腳組成的水平型熱電模組，並通過濺鍍Ni/Ag雙層膜作為電極串接，該模組可在55 ℃的溫差下得到約6.09 mW/cm2的最佳功率密度輸出，換算成模組效率因子為2.02 μW/cm2·K2。另外，我們亦提出了一種新型的集熱端設計，除提高集熱效率外，更能提升水平型厚膜模組的實用性。

Bismuth telluride-based compounds have been widely employed in commercial thermoelectric devices because of their superior thermoelectric properties at low temperature regime. A typical thermoelectric generator consists of pairs of n- and p-type thermoelectric elements bonded between two ceramic substrates with metal connectors. However, most heat sources may have irregular-shaped surface in practical application scenario, which may cause a poor contact between the rigid thermoelectric devices and heat source. Conversely, the thermoelectric films printed on a flexible substrate is beneficial for harvesting thermal energy from the heat source with irregular contact schemes, and is highly suitable for making low-power (μW – mW) generators from environment with the presence of small temperature difference. In this study, we prepared both p-type (Bi-Sb-Te) and n-type (Bi-Te-Se) films of several tens of micrometer on a polyimide substrate by screen printing and pressured curing treatment. The p-type and n-type thermoelectric films exhibit a power factor of 1.43 mW/K2m and 0.84 mW/K2m, respectively, after optimizing process temperature and pressure. A planar thermoelectric module was demonstrated by preparing 3 pairs of thermoelectric legs on a polyimide substrate and were electrically connected by Ni/Ag bilayer stripes. The thick film module can achieve an output power density of 6.09 mW/cm2 under a temperature difference of 55 ℃, and have the thermoelctric efficiency factor about 2.02 μW/cm2·K2. In addition, we also proposed a newly designed module, which has high heat collection efficiency for improve energy harvesting applications.

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