Control of Structure and Thermoelectric Properties of Chalcopyrite Compounds by using Room-temperature High-pressure Synthesis

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05548
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Structural/Functional materials
• Research Institution: Osaka Prefecture University
• Principal Investigator: KOSUGA Atsuko 大阪府立大学, 理学(系)研究科(研究院), 准教授 (30379143)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 熱電材料 / カルコパイライト / 熱的特性 / 電気的特性 / 第一原理計算

Outline of Final Research Achievements

The effect of room-temperature high-pressure (RTHP) treatment on the transport properties, crystal structure, and electronic structure of chalcopyrite compounds were investigated. The thermal conductivity of RTHP-treated chalcopyrite compounds is greatly reduced, which is attributed to the point defects, stacking faults, and increased grain boundaries. These defects also decrease the carrier mobility and increase the carrier concentration, resulting in lowering the electrical conductivity and Seebeck coefficient. RTHP-treated chalcopyrite compounds contains microstrains, which partially arises from a series of disorder at the cation site with a variety of degrees and geometries. Such disorder can be induced as a metastable structure by the RTHP-treatment. Electronic structure calculations clarify that such disorder at the cation site changes orbitals hybridization, which can partially explain the experimentally observed transport properties of RTHP-treated samples.

Free Research Field

エネルギー材料工学