Spectroscopic evidence of preferential excitation of interfacial Eu-III by interfacial energy transfer process on core@shell nanoparticles

Autor(es)

Diogenis, Isabela M. S. ^[1] ; Rodrigues, Emille M. ^[1] ; Mazali, Italo O. ^[1] ; Sigoli, Fernando A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Chem, Lab Funct Mat, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Luminescence; v. 232, APR 2021.
• Citações Web of Science: 2

Resumo

The hierarchical core@shell nanostructure in upconversion nanoparticle (UCNP) has allowed high intensities of upconversion emission by interfacial energy transfer (IET) mechanism, which can also account for high down-shifting emission intensities observed for core@shell nanostructures. It is well accepted that the emission of active ions, sensitized by IET is originated from ions located into narrow core@shell interface, which has been shown by physically separation of donor and acceptor ions in the core@shell nanostructure. Herein we have spectroscopic proof of the preferential sensitization of the ions into the core@shell interface by IET. We have analyzed the excitation and emission spectra profiles of the Eu-III sensitized by Gd-III ions on hierarchically structured beta-NaYF4 nanoparticles. In this work, Eu-III emission occurs through a downshifting mechanism that is like the last step of the energy transfer pathway from Gd-III to active ions in nanostructured UCNPs as part of a known UC-IET processes. Photophysical results indicate that IET sensitizes mainly the Eu-III ions located at the core@shell interface, where these ions experience a variety of distorted chemical environments. Such a non-symmetrical electrical fields results in an inomogeneous broadening of D-5(0) -> F-7(2) transition emission band. The preferential, but not unique, sensitization of Eu-III ions by energy transfer from Gd-III ions located at distorted interface may shine light on the upconversion emission bands intensities observed in several works describing the IET in UCNPs and spectrocopically confirms that Gd-III-mediated emission occurs spatially in a narrow core@shell interfacial region. (AU)

• Processo FAPESP: 14/50906-9 - INCT 2014: em Materiais Complexos Funcionais (INOMAT)
• Beneficiário: Fernando Galembeck
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/22127-2 - Desenvolvimento de novos materiais estratégicos para dispositivos analíticos integrados
• Beneficiário: Lauro Tatsuo Kubota
• Modalidade de apoio: Auxílio à Pesquisa - Temático