二維材料熱電材料的優勢及其檢測技術

The advantages of two-dimensional thermoelectric materials and its measurements methodology

隨著社會對再生能源應用的重視，熱電材料的研究受到了巨大的關注。傳統的無機及有機材料讓熱電在過去幾十年有了顯著的改善。而與傳統材料相比，二維材料由於其獨特的層狀結構及材料的多樣性提供了熱電材料發展新的方向。更重要的是，它可透過聲子介面散射機率的增加(enhance phonon scattering)來大幅降低熱導率並維持電導率。此結果不僅表現出更優異的性能並且更有利於設計及改進熱電元件的性能。但是由於二維材料的晶體厚度遠小於三維材料，許多用於傳統的三維的量測技術因實驗設置困難或對平面的熱傳導敏感度不佳，不適用於二維材料，使二維熱電量測面臨極大的挑戰。直到現在，仍然缺乏通用的標準來精確的測量二維材料。近幾年，許多科學家發展出一些適合應用於二維材料的量測設備與技術。在此篇文章中，我們主要將介紹二維材料在熱電上的優勢與回顧這些適用的二維量測方法，相信有利於計算出二維材料的熱電優值因數（ZT）與未來的熱電發展。

As society attaches the importance to the application of renewable energy, the research of thermoelectric materials has received much more attention. In contrast to the traditional inorganic and organic material, which have made a huge improvement in thermoelectric field over the past decades, two-dimensional materials provide a new direction for the thermoelectric materials development because of their unique of layered structure and the diversity of material. Furthermore, by enhancing the phonon scattering probability, two-dimensional materials can reduce the thermal conductivity and maintain the electrical conductivity which result in not only a better performance but also an advantage in designing and improving the thermoelectric devices. However, due to the thickness of two-dimensional materials is much smaller than the three-dimensional materials, many traditional measurements methodology designs for three-dimensional materials are not suitable for two-dimensional materials owing to some difficulty in experimental setup or low sensitivity to in-plane heat transportation.
Until now, there is still a lack of universal standards to accurately measure two-dimensional materials. In recent years, many scientists have developed some measurements and techniques for two-dimensional materials. In this article, we will mainly introduce the advantages of two-dimensional materials in the thermoelectric devices and review these applicable two-dimensional measurement methods. We believe that it will help to determine the thermoelectric performance (ZT) of two-dimensional materials and develop the future of thermoelectrics.