Autor(es):
Costa Macedo, Wagner [UNESP] ; Germano Bispo Junior, Airton [UNESP] ; de Oliveira Rocha, Kleper [UNESP] ; de Souza Albas, Agda Eunice [UNESP] ; Pires, Ana Maria [UNESP] ; Rainho Teixeira, Silvio [UNESP] ; Longo, Elson
Data: 2020
Identificador Persistente: http://hdl.handle.net/11449/201597
Origem: Oasisbr
Assunto(s): Luminescence; Microwave-assisted hydrothermal method; Red-emitting phosphors; Solid-state lighting; Luminescence; Luminescence; Microwave-assisted hydrothermal method; Microwave-assisted hydrothermal method; Red-emitting phosphors; Red-emitting phosphors; Solid-state lighting; Solid-state lighting
Descrição
Made available in DSpace on 2020-12-12T02:36:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Eu-doped 1, 3 and 5 % CaZrO3 red-emitting phosphors were synthesized for the first time using the microwave-assisted hydrothermal method followed by heat treatment at 1200 °C. After the crystallization, the orthorhombic CaZrO3 and the non-stoichiometric cubic Ca0.15Zr0.85O 1.85 phases were identified for all samples, and the portion of the non-stoichiometric phase increases as the Eu3+ concentration increases. The excitation spectra of the phosphors display Eu3+ f-f excitation bands (namely at 395 nm and 464 nm) and the Eu3+→O2- charge transfer band at 250 nm, confirming that the CaZrO3 host acts as sensitizer for the Eu3+ luminescence. Likewise, the emission spectra feature the typical Eu3+ emission within the red spectral region, displaying CIE color coordinates of (0.642; 0.332), (0.663; 0.330) and (0.668; 0.327) for the 1, 3 and 5 % doped samples, respectively, indicating high emission color purity. By using Eu3+ as spectroscopic probe, the high-resolution selective emission spectra (14 K) confirm that Eu3+ replaces Ca2+ and Zr4+ local sites in both CaZrO3 and the Ca0.15Zr0.85O1.85 phases. Finally, the high absolute emission quantum yield of the 3 %-doped phosphor found at 393 nm (0.29 ± 0.03) confirms its potential application as red-emitting phosphor, especially in rapid identification of latent fingerprints, security ink or as red-emitting coating of near-UV LEDs for WLED applications.
São Paulo State University (UNESP) Dept. of Physics and Dept. of Chemistry
São Paulo State University (UNESP) Dept. of Chemistry
Federal University of São Carlos (UFSCar) CDMF
São Paulo State University (UNESP) Dept. of Physics and Dept. of Chemistry
São Paulo State University (UNESP) Dept. of Chemistry
CNPq: 573636/2008-7
