Autor(es)

Goncalves, Joao M. ; Bastos, Ana R. N. ; Ribeiro, Sidney J. L. ; Carlos, L. D. ; Longo, Ricardo L. ; Caiut, Jose Mauricio A. ; Ferreira, Rute A. S.

• Tipo de documento: Artigo Científico
• Fonte: NANOSCALE ADVANCES; v. 6, n. 5, p. 11-pg., 2024-02-14.

Resumo

Luminescent nanoparticles have shown great potential for thermal sensing in bio-applications. Nonetheless, these materials lack water dispersibility that can be overcome by modifying their surface properties with water dispersible molecules such as cysteine. Herein, we employ LiYF4:Er3+/Yb3+ upconverting nanoparticles (UCNPs) capped with oleate or modified with cysteine dispersed in cyclohexane or in water, respectively, as thermal probes. Upconversion emission was used to sense temperature with a relative thermal sensitivity of similar to 1.24% K-1 (at 300 K) and a temperature uncertainty of 0.8 K for the oleate capped and of 0.5 K for cysteine modified NPs. To study the effect of the cysteine modification in the heat transfer processes, the thermal conductivity of the nanofluids was determined, yielding 0.123(6) W m(-1) K-1 for the oleate capped UCNPs dispersed in cyclohexane and 0.50(7) W m(-1) K-1 for the cysteine modified UCNPs dispersed in water. Moreover, through the heating curves, the nanofluids' thermal resistances were estimated, showing that the cysteine modification partially prevents heat transfer. (AU)

• Processo FAPESP: 19/18828-1 - Materiais nano e/ou submicroparticulados à base de íons lantanídeos com potencial aplicação em fotônica
• Beneficiário: José Maurício Almeida Caiut
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/11670-5 - NANOMATERIAIS e SISTEMAS LUMINESCENTES BASEADOS EM ÍONS TERRAS RARAS
• Beneficiário: José Maurício Almeida Caiut
• Modalidade de apoio: Auxílio à Pesquisa - Regular