Unraveling the Role of Sn Segregation in the Electronic Transport of Polycrystalline Hematite: Raising the Electronic Conductivity by Lowering the Grain-Boundary Blocking Effect

Author(s)

Soares, Mario R. S. ^[1] ; Costa, Carlos A. R. ^[2] ; Lanzoni, Evandro M. ^[2] ; Bettini, Jefferson ^[2] ; Ramirez, Carlos A. O. ^[2] ; Souza, Flavio L. ^[3] ; Longo, Elson ^[1] ; Leite, Edson R. ^{[2, 1]}

Affiliation

^[1] Univ Fed Sao Carlos, Chem Dept, BR-13565905 Sao Carlos, SP - Brazil

^[2] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas, SP - Brazil

^[3] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: ADVANCED ELECTRONIC MATERIALS; v. 5, n. 6 JUN 2019.
• Web of Science Citations: 0

Abstract

This paper describes the role of SnO2 in the electronic transport of polycrystalline hematite (alpha-Fe2O3). The proper sintering process allows for freezing of a state of electronic defects, in which the electrical properties of hematite are controlled by the grain boundary and Sn segregation. Impedance spectroscopy and dc conductivity measurements show that current flows through preferential pathways associated with Sn segregation that occurs at the grain boundary, leading to a decrease in grain-boundary resistance. Atomic force microscopy and electric force microscopy measurements confirm the results of the impedance analysis. The identification of preferential grain boundaries for electrical conductivity may have a direct influence on the light-induced water-splitting performance of the hematite photoanode. (AU)

• FAPESP's process: 17/03135-5 - Grain boundary in electro-ceramic materials: understanding nature and its function in the hematite (Fe2O3)
• Grantee: Edson Roberto Leite
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
• Grantee: Adalberto Fazzio
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC