Controlling the thermal switching in upconverting nanoparticles through surface chemistry

Author(s)

Martinez, Eduardo D. ^[1] ; Garcia-Flores, Ali F. ^[2] ; Carneiro Neto, Albano N. ^[3] ; Brites, Carlos D. S. ^[3] ; Carlos, Luis D. ^[3] ; Urbano, Ricardo R. ^[2] ; Rettori, Carlos ^{[4, 2]}

Affiliation

^[1] Consejo Nacl Invest Cient & Tecn, Ctr Atom Bariloche, Comis Nacl Energia Atom CNEA, Inst Nanociencia & Nanotecnol INN, Av E Bustillo 9500, RB402AGP, San Carlos De Bariloche, Rio Negro - Argentina

^[2] Univ Estadual Campinas, UNICAMP, Gleb Wataghin Inst Phys IFGW, BR-13083859 Campinas, SP - Brazil

^[3] Univ Aveiro, Phys Dept, CICECO, Aveiro Inst Mat, Phantom G, P-3810193 Aveiro - Portugal

^[4] Fed Univ ABC UFABC, CCNH, BR-09210580 Santo Andre, SP - Brazil

• Document type: Journal article
• Source: NANOSCALE; v. 13, n. 38 AUG 2021.
• Web of Science Citations: 0

Abstract

Photon upconversion taking place in small rare-earth-doped nanoparticles has been recently observed to be thermally modulated in an anomalous manner, showing thermal enhancement of the emission intensity. This effect was proved to be linked to the role of adsorbed water molecules as surface quenchers. The surface capping of the particles has a direct influence on the thermal dynamics of water adsorption and desorption, and therefore on the optical properties. Here, we show that the upconversion intensity of small-size (<25 nm) nanoparticles co-doped with Yb3+ and Er3+ ions, and functionalized with different capping molecules, presents clear irreversibility patterns upon thermal cycling that strongly depend on the chemical nature of the nanoparticle surface. By performing temperature-controlled luminescence measurements we observed the formation of a thermal hysteresis loop, resembling an optical switching phenomenon, whose shape and trajectory depend on the hydrophilicity of the surface. Additionally, an intensity overshoot takes place immediately after turning off the heating source, affecting each radiative transition differently. We performed numerical modelling to understand this effect considering non-radiative energy transfer from the surface defect states to the Er3+ ions. These findings are relevant for the comprehension of nanoparticle-based luminescence and the interplay between the surface and volume effects, and more generally, for applications involving UCNPs such as nanothermometry and bioimaging, and the development of optical encoding systems. (AU)

• 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: 12/04870-7 - Studies of novel complex and advanced materials
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Research Projects - Thematic Grants
• 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: 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
• 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: 17/10581-1 - Emergent phenomena in reduced dimension systems
• Grantee: Pascoal Jose Giglio Pagliuso
• Support Opportunities: Special Projects
• 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