Charge dynamics in semiconductors for photoelectrochemical water splitting

Author(s)

Santos, Ana M. S. ; Rodriguez-Gutierrez, Ingrid ; Morishita, Gustavo M. ; Lopes, Ricardo M. ; Souza, Flavio L.

• Document type: Journal article
• Source: Materials Letters; v. 357, p. 4-pg., 2023-12-19.

Abstract

This letter focuses on monitoring alterations in the charge carrier dynamics associated with in-situ modifications into hematite photoanodes, employing advanced electrochemical techniques. A simple and scalable polymeric precursor solution, deposited by spin-coating, was employed to synthesize hematite based photoanodes. Among various modifications, Tantalum (Ta+5) shows the most promising results, yielding a hydrogen production rate of 24.0 mu mol cm-2h-1 at 1.23VRHE. This is attributed to Ta5+ segregation at hematite grain surface, which facilitates the charge transport efficiency and leads to higher external quantum efficiency. Conversely, sodium (Na+) primarily increases the film thickness with limited observable effects on charge carrier dynamics, while zinc (Zn+2) adversely affects hematite performance due to its negative effect on charge separation efficiency and increased bulk recombination. (AU)

• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 17/02317-2 - Interfaces in materials: electronic, magnetic, structural and transport properties
• Grantee: Adalberto Fazzio
• Support Opportunities: Research Projects - Thematic Grants