Investigating the thermally induced p-n transition in reduced graphene oxide layers exposed to hydrogen sulfide

Autor(es)

Ruiz, Elisa ; Varenne, Christelle ; De Lima, Bruno S. ; Gueye, Thiaka ; Pauly, Alain ; Mastelaro, Valmor R. ; Brunet, Jerome ; Ndiaye, Amadou L.

• Tipo de documento: Artigo Científico
• Fonte: SENSORS AND ACTUATORS B-CHEMICAL; v. 409, p. 10-pg., 2024-03-14.

Resumo

To investigate the origin of the p -n transition observed in graphene-based materials for chemical sensors, we developed sensing layers made of chemically reduced graphene oxide (rGO), prepared from graphene oxide (GO) using citrate as a reducing agent. We focused mainly on the thermally induced p -n transition when the sensing layers are exposed to H2S at a specific temperature. The rGO sensing layers are prepared through drop casting on interdigitated electrodes. Scanning electron and transmission electron microscopes allow the characterization of the rGO structure, while FTIR, X-ray photoelectron spectroscopy, and electrical characterization have revealed the reduction efficiency. The p -n transition occurs between 80 degrees C and 90 degrees C, whatever the resistance range and the exposition history to H2S. The temperature -dependent transition, which starts around 80-90 degrees C, is reversible if the temperature is kept below 80 degrees C, i.e., the rGO remains p -type material. When experiments are performed at a temperature above 90 degrees C, the transition from p -type to n -type takes place, and the n -type persists, showing an irreversible transition. The transition starts gradually at 80 degrees C during lower concentration exposure and ends at high concentration. Finally, the results show that temperature and H2S contribute to the inversion of the initial charge carriers. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 18/07517-2 - Compósitos de grafeno e óxidos metálicos: aplicação como sensores de gases tóxicos
• Beneficiário: Bruno Sanches de Lima
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado