Unveiling the dopant segregation effect at hematite interfaces

Author(s)

de Lima, Felipe C. ^[1] ; Schleder, Gabriel R. ^{[2, 1]} ; Souza Junior, Joao B. ^[1] ; Souza, Flavio L. ^{[2, 1]} ; Destro, Fabricio B. ^[3] ; Miwa, Roberto H. ^[4] ; Leite, Edson R. ^{[5, 1]} ; Fazzio, Adalberto ^{[2, 1]}

Affiliation

^[1] Brazilian Nanotechnol Natl Lab, CP 6192, BR-13083970 Campinas, SP - Brazil

^[2] Fed Univ ABC, BR-09210580 Santo Andre, SP - Brazil

^[3] Fed Univ Sao Carlos UFSCar, Dept Mat Engn, Grad Program Mat Sci & Engn, BR-13565905 Sao Carlos, SP - Brazil

^[4] Univ Fed Uberlandia, Inst Fis, CP 593, BR-38400902 Uberlandia, MG - Brazil

^[5] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos - Brazil

• Document type: Journal article
• Source: Applied Physics Letters; v. 118, n. 20 MAY 17 2021.
• Web of Science Citations: 1

Abstract

Understanding the effects of atomic structure modification in hematite photoanodes is essential for the rational design of high-efficiency functionalizations. Recently, it was found that interface modification with Sn/Sb segregates considerably increases hematite photocatalytic efficiency. However, the understanding of the different electronic effects of these modifications at the atomic level is still lacking. This Letter describes the segregation effects of two different dopants-Sn and Sb-on both the solid-solid (grain boundaries) and solid-liquid interfaces (surfaces) of hematite. Within an ab initio approach, we quantitatively extract the potential barrier reduction on polycrystalline interfaces due to the dopant, which causes an increase in the inter-grain electron transport. Concomitantly, the dopants' segregation on hematite surfaces results in a decrease in the oxygen vacancy formation energy. Such vacancies lead to the experimentally observed rise of the flatband potential. The comprehension of the electronic effects of dopants on both types of interfaces explains the experimental peak efficiency of interface-modified hematite with dopant segregates, also enabling the control and design of interfaces for different higher-efficiency applications. (AU)

• FAPESP's process: 18/05159-1 - Static and dynamic self-assembly of inorganic nanoparticles
• Grantee: João Batista Souza Junior
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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: 17/18139-6 - Machine learning for Materials Science: 2D materials discovery and design
• Grantee: Gabriel Ravanhani Schleder
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/20857-0 - Two-dimensional materials and topological phases: prediction and control of its properties
• Grantee: Felipe David Crasto de Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• 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