Banca de DEFESA: JAMERSON FONSECA DE SOUSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JAMERSON FONSECA DE SOUSA
DATE: 24/03/2023
TIME: 09:00
LOCAL: Ambiente virtual
TITLE:

Generation of visible light and study of energy-transfer in TeO2:ZnO glass doped and co-doped with  Dy3+/Pr3+ and Eu3+/Ho3+

KEY WORDS:

Rare – Earth. Glasses. Luminescence. Energy Transfer

PAGES: 114
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUBÁREA: Física da Matéria Condensada
SPECIALTY: Prop. Óticas e Espectrosc. da Mat. Condens; Outras Inter. da Mat. com Rad. e Part.
SUMMARY:

In this work, we carried out a spectroscopic study of glass based on Tellurium and Zinc oxides (xTeO2:yZnO) doped and co-doped with Dy3+, Pr3+, Eu3+ and Ho3+ ions under UV and blue excitation. The analysis of this investigation were based on measurements of optical absorption and excitation, luminescence, time-resolved luminescence and energy transfer efficiency parameters. The results show that under UV/blue excitation the co-doped systems generate well-defined emission bands in the visible region, and the behavior of the emission intensity as a function of the co-dopant concentration indicated the presence of energy transfer mechanisms Dy3+ → Pr3+, Pr3+ → Dy3+, Eu3+ → Ho3+ e Ho3+ → Eu3+, which were later confirmed by lifetime measurements. The analysis of energy transfer efficiencies indicated that transfers according to Dy3+ → Pr3+ e Ho3+ → Eu3+ Dy3+ → Pr3+ and Ho3+ → Eu3+ mechanisms are more efficient and, therefore, are more likely to occur. It was also observed that the emissions are sensitive to the excitation wavelengths used, and furthermore, these excitations are responsible for altering the sensitizer/acceptor relationship in the energy transfer process, showing, therefore, that the spectral profile of the emissions is a function not only of the concentration of the ions, but also of the excitation used and consequently of the energy transfer. The results presented here may impact studies that explore the optical properties of devices based on the light emitted by Dy3+/ Pr3+ and Eu3+/ Ho3+ ion pairs

BANKING MEMBERS:
Presidente - 2120537 - ARTUR DA SILVA GOUVEIA NETO
Interno(a) - 048.326.254-46 - FRANCISCO DE ASSIS MARTINS GOMES REGO FILHO - IFAL
Externo(a) ao Programa - 1120709 - MARIA TEREZA DE ARAUJO
Externo(a) à Instituição - LUCIANO AVALLONE BUENO - UFABC
Externo(a) à Instituição - ERNANDE BARBOSA DA COSTA - UFRPE