Composition Control and Thermoelectric Properties of Quaternary Chalcogenide Nanocrystals: The Case of Stannite Cu2CdSnSe4

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• 作者：Maria Ib谩帽ez ; Doris Cadavid ; Reza Zamani ; Nuria Garc铆a-Castell贸 ; Victor Izquierdo-Roca ; Wenhua Li ; Andrew Fairbrother ; Joan Daniel Prades ; Alexey Shavel ; Jordi Arbiol ; Alejandro P茅rez-Rodr铆guez ; Joan Ramon Morante ; Andreu Cabot
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：February 14, 2012
• 年：2012
• 卷：24
• 期：3
• 页码：562-570
• 全文大小：772K
• 年卷期：v.24,no.3(February 14, 2012)
• ISSN：1520-5002

文摘

A high-yield and upscalable colloidal synthesis route for the production of quaternary I₂鈥揑I鈥揑V鈥揤I₄ nanocrystals, particularly stannite Cu_2+xCd_1鈥?i>xSnSe₄, with narrow size distribution and precisely controlled composition is presented. It is also shown here how the diversity of valences in the constituent elements allows an effective control of their electrical conductivity through the adjustment of the cation ratios. At the same time, while the crystallographic complexity of quaternary chalcogenides is associated with intrinsically low thermal conductivities, the reduction of the lattice dimensions to the nanoscale further reduces the materials thermal conductivity. In the specific case of the stannite crystal structure, a convenient slab distribution of the valence band maximum states permits a partial decoupling of the p-type electrical conductivity from both the Seebeck coefficient and the thermal conductivity. Combining these features, we demonstrate how an initial optimization of the nanocrystals Cd/Cu ratio allowed us to obtain low-temperature solution-processed materials with ZT values up to 0.71 at 685 K.

Keywords:

nanocrystal; chalcogenide; thermoelectric; colloidal synthesis; stannite; semiconductor nanoparticle