Thermoplasmonic enhancement of upconversion in small-size doped NaGd(Y)F-4 nanoparticles coupled to gold nanostars

Author(s)

Martinez, Eduardo D. ^[1] ; Urbano, Ricardo R. ^[1] ; Rettori, Carlos ^{[2, 1]}

Affiliation

^[1] Univ Estadual Campinas, UNICAMP, Gleb Wataghin Inst Phys, BR-13083859 Campinas, SP - Brazil

^[2] Fed Univ ABC UFABC, CCNH, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: NANOSCALE; v. 10, n. 30, p. 14687-14696, AUG 14 2018.
• Web of Science Citations: 5

Abstract

Plasmon enhancement of luminescence is a common strategy to boost the efficiency of both fluorescence and upconversion via the augmented local electromagnetic field. However, the local heating produced when exciting the plasmon resonance of metallic nanoparticles is often overlooked. As higher temperatures are usually detrimental for radiative processes, only the electromagnetic contribution is exploited for enhancement. We show here that for small size (<20 nm) rare-earth doped -NaGd(Y)F-4 upconversion nanoparticles (UCNPs), the photothermal properties of gold nanostars (AuNSs) can be used to enhance the total emission intensity. On the contrary, for UCNPs of larger size, the thermoplasmonic effect is adverse for the emissivity. Therefore, we developed a novel strategy to enhance the emission intensity by combining the thermoplasmonic effect on AuNSs with the size-dependent thermal properties of UCNPs. Furthermore, by following the integrated intensity ratio between the emission lines of Er3+, H-2(11/2) I-4(15/2) and S-4(3/2) I-4(15/2), a direct correlation between the local temperature and the emission intensity could be established. Optical thermometry measurements show that the thermoplasmonic effect in AuNSs, with a plasmon absorption band close to the excitation wavelength, can produce an increment of the local temperature of more than 100 degrees C when exposed to 976 nm continuous-wave laser light at 50 W cm(-2) of power density. The results provided here are relevant for the design and implementation of plasmon-enhanced luminescent devices, upconversion solar-cells, bioprobes and also for hyperthermia. (AU)

• FAPESP's process: 15/23882-4 - PLASMONIC EFICIENCY INTENSIFICATION OF THE UPCONVESION IN NANOCRYSTAIS DOPED WITH RARE EARTHS.
• Grantee: Eduardo David Martínez
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/04870-7 - Studies of novel complex and advanced materials
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/21289-4 - Multi-User Equipment in grant 12/04870-7 - desktop X-ray powder diffractometer
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 12/05903-6 - Nuclear magnetic resonance of novel complex and advanced materials in condensed matter physics
• Grantee: Ricardo Rodrigues Urbano
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 15/21290-2 - Multi-User Equipment in grant 12/04870-7 - dynamic light scattering analyser Horiba SZ-100Z
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 11/19924-2 - Study and development of advanced novel materials: electronic, magnetic and nanostructured: an interdisciplinary approach
• Grantee: Carlos Rettori
• Support Opportunities: Research Projects - Thematic Grants