Photon-avalanche-like upconversion in NdAl3(BO3)4 nanoparticles excited at 1064 nm

Silva, Jefferson Ferreira da; Silva, Rodrigo Ferreira da; Santos, Emanuel P.; Maia, Lauro June Queiroz; Moura, André de Lima

Photon-avalanche-like upconversion in NdAl3(BO3)4 nanoparticles excited at 1064 nm

Data

2020

Autores

Silva, Jefferson Ferreira da

Silva, Rodrigo Ferreira da

Santos, Emanuel P.

Maia, Lauro June Queiroz

Moura, André de Lima

Resumo

We report efficient nonresonant ground-state excitation at 1064 nm of trivalent neodymium (Nd3þ) ions in stoichiometric neodymium aluminum borate NdAl3(BO3)4 nanoparticles, which are crystalline and, besides the large content of Nd3þ ions, present excellent photoluminescence properties. Upconversion (UC) emission was observed, and the energy pathways were identified starting from multi-phonon assisted ground-state absorption (4 I9/2 ! 4 F3/2) and excited-state absorption (4 I11/2 ! 4 F3/2) with the population of the 4 I11/2 level by thermal coupling with the ground state. The excited state 4 I11/2 is also populated by relaxations of the Nd3þ ions at upper-lying levels. Crossrelaxation between two Nd3þ ions (4 F3/2, 4 I9/2) ! ( 4 I15/2, 4 I15/2) with subsequent phonon emission leads to two ions at the 4 I11/2 level, with every iteration triggering a photon-avalanche-like emission, which greatly enhances the efficiency of the UC emissions. Ladder thermal excitation 4 F3/2 ! ( 4 F5/2, 2 H9/2) ! ( 4 F7/2, 4 S3/2) ! 4 F9/2 was achieved, and the ground-state relaxation from these levels provided emission at 880 nm, 810 nm, 750 nm, and 690 nm, respectively. Energy transfer UC (Auger) between Nd3þ ions at the 4 F3/2 level allowed the population of (2 G3/2, 4 G7/2) from which relaxations to the 4 I9/2, 4 I11/2, and 4 I13/2 states provided emissions around 536 nm, 600 nm, and 660 nm, respectively. Associated with the nonradiative relaxations, we observed the heating of the nanoparticles (22 C–240 C) with subsequent thermal enhancement of the frequency UC emissions due to population redistribution between the coupled energy levels of the Nd3þ ions. The present results have potential applications in super-resolution imaging and nanothermometry.

Citação

SILVA, Jefferson F. da. Photon-avalanche-like upconversion in NdAl 3 (BO 3 ) 4 nanoparticles excited at 1064-nm. Applied Physics Letters, College Park, v. 117, n. 15, e151102, 2020. DOI: 10.1063/5.0024619. Disponível em: https://pubs.aip.org/aip/apl/article/117/15/151102/39270/Photon-avalanche-like-upconversion-in-NdAl3-BO3-4. Acesso em: 7 fev. 2024.