Optical oxygen sensing by MPA-capped CdTe quantum dots immobilized in mesoporous silica

Autor(es)

Ravaro, Leandro P. ^{[1, 2]} ; Ford, Peter C. ^[1] ; de Camargo, Andrea S. S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Calif Santa Barbara, Dept Chem & Biochem, Santa Barbara, CA 93106 - USA

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Microporous and Mesoporous Materials; v. 303, AUG 15 2020.
• Citações Web of Science: 0

Resumo

A novel nanocomposite luminescent material was prepared by taking advantage of the versatile wet impregnation method for the dispersion of CdTe quantum dots (QDs) into mesoporous silica host matrix and thus providing great interaction between oxygen and QDs, with potential application in an optical oxygen sensor. The optical/spectroscopic properties of the QDs suspended in aqueous media and incorporated in mesoporous silica were evaluated as a function of aging time, temperature variation and oxygen concentration. Luminescence quenching studies were carried out for both QDs suspended in solution and loaded into the silica matrix, in the presence of varying O-2 concentration. By Stern-Volmer plot analysis, obtained at different temperatures, it was possible to verify the existence of two types of emission quenching mechanisms for CdTe QDs. After aging for 120 days at room temperature, the QDs in colloidal suspension displayed a small red-shifted emission, which was interpreted as a decreased bandgap energy owing to the increase in the nanocrystal size. In contrast, the emission spectrum of CdTe QDs loaded into the mesoporous SiO2 matrix remained unchanged after aging for the same time at ambient temperature. The presented results will contribute to the discernment of oxygen quenching mechanisms and chemical stability of optical sensors based on CdTe QDs. (AU)

• Processo FAPESP: 13/24727-7 - Novos materiais ópticos baseados em Complexos Polinucleares de Clusters de Haleto de Cobre(I) imobilizados em matrizes hospedeiras sólidas
• Beneficiário: Leandro Piaggi Ravaro
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/17495-0 - Novos materiais fotônicos baseados em complexos de Cu(I), nanopartículas conversoras ascedentes de energia e pontos quânticos
• Beneficiário: Leandro Piaggi Ravaro
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado