本文關(guān)鍵詞：Ag-ZnO納米復(fù)合熱電材料的制備及其性能研究，，由筆耕文化傳播整理發(fā)布。

Ag-ZnO納米復(fù)合熱電材料的制備及其性能研究

Preparation and thermoelectric properties of Ag-ZnO nanocomposites synthesized by means of sol-gel

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Wu Zi-Hua Xie Hua-Qing Zeng Qing-Feng （ School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209, China ）

上海第二工業(yè)大學城市建設(shè)與環(huán)境工程學院,上海201209

文章摘要：ZnO是一類具有潛力的熱電材料,但其較大聲子熱導(dǎo)率影響了熱電性能的進一步提高.納米復(fù)合是降低熱導(dǎo)率的有效途徑.本文以醋酸鹽為前驅(qū)體,溶膠-凝膠法制備了Ag-ZnO納米復(fù)合熱電材料.掃描電鏡照片顯示ZnO顆粒呈現(xiàn)多孔結(jié)構(gòu), Ag納米顆粒分布于ZnO的晶粒之間. Ag-ZnO納米復(fù)合材料的電導(dǎo)率比未復(fù)合ZnO材料高出100倍以上,而熱導(dǎo)率是未復(fù)合ZnO材料的1/2. 同時, 隨著 Ag 添加量的增加, 賽貝克系數(shù)的絕對值逐漸減小. 綜合以上原因,添加7.5%mol Ag的Ag-ZnO納米復(fù)合材料在700 K時的熱電優(yōu)值達到0.062,是未復(fù)合ZnO材料的約25倍.在ZnO基體中添加導(dǎo)電金屬顆粒有利于產(chǎn)生導(dǎo)電逾滲通道,提高材料體系的電導(dǎo)率,但同時導(dǎo)致賽貝克系數(shù)的絕對值減小.總熱導(dǎo)率的差異來源于聲子熱導(dǎo)率的差異.位于ZnO晶界的納米Ag顆粒,有利于降低聲子熱導(dǎo)率.

Abstr：Zinc oxide （ZnO） has attracted increasing attention as one of the most promising n-type thermoelectric materials. Although ZnO has been screened for high power factor, the ZT results were discouraging for its high thermal conductivity. Preparing nanocomposite is an effective way to reduce the thermal conductivity. The Ag-ZnO nanocomposites were synthesized by means of sol-gel method and their thermoelectric properties were investigated. Their XRD pattern and SEM miro graphs show that Ag nanoparticles are mainly lecated at the grain boundary of ZnO. Increasing Ag content leads to a significant decrease in absolute value of Seebeck coefficient （｜S｜）. The electrical conductivity increases with increasing Ag content, while the thermal conductivity of Ag-ZnO nanocomposites is much lower than the bulk ZnO sample. The highest ZT （0.062） is found for 7.5 mol% [email protected] nanocomposite at 750 K, thirty-five times of that of bulk ZnO. Since the Ag–ZnO junction leads to charge redistribution, the deflexed energy band obtained for ZnO should facilitate the electron transfer across the interface and thus accelerates the mobility of charge carriers. Thus increasing mobility of charge carriers would lead to the increase in electrical conductivity and a decrease in Seebeck coefficient. The difference of thermal conductivity comes from the lattice thermal conductivity. Due to the high density of interfaces and grain boundaries present in the nanocomposites, the scattering of phonons across a broad wavelength spectrum is enhanced. This suppresses the lattice thermal conductivity of the nanocomposites significantly.

文章關(guān)鍵詞：

Keyword：:thermolelectric materials ZnO nanocomposite thermal conductivity

課題項目：國家自然科學基金（批準號： 51206103）;上海市教委科研創(chuàng)新項目（批準號： 13YZ128）;上海市東方學者崗位支持計劃資助的課題

作者信息：會員可見

  本文關(guān)鍵詞：Ag-ZnO納米復(fù)合熱電材料的制備及其性能研究，由筆耕文化傳播整理發(fā)布。