Highly Efficient Green-Emitting Phosphors Ba2Y5B5O17 with Low Thermal Quenching Due to Fast Energy Transfer from Ce3+ to Tb3.
Inorg Chem
; 56(8): 4539-4545, 2017 Apr 17.
Article
em En
| MEDLINE
| ID: mdl-28358516
ABSTRACT
This paper demonstrates a highly thermally stable and efficient green-emitting Ba2Y5B5O17Ce3+, Tb3+ phosphor prepared by high-temperature solid-state reaction. The phosphor exhibits a blue emission band of Ce3+ and green emission lines of Tb3+ upon Ce3+ excitation in the near-UV spectral region. The effect of Ce3+ to Tb3+ energy transfer on blue to green emission color tuning and on luminescence thermal stability is studied in the samples codoped with 1% Ce3+ and various concentrations (0-40%) of Tb3+. The green emission of Tb3+ upon Ce3+ excitation at 150 °C can keep, on average, 92% of its intensity at room temperature, with the best one showing no intensity decreasing up to 210 °C for 30% Tb3+. Meanwhile, Ce3+ emission intensity only keeps 42% on average at 150 °C. The high thermal stability of the green emission is attributed to suppression of Ce3+ thermal de-excitation through fast energy transfer to Tb3+, which in the green-emitting excited states is highly thermally stable such that no lifetime shortening is observed with raising temperature to 210 °C. The predominant green emission is observed for Tb3+ concentration of at least 10% due to efficient energy transfer with the transfer efficiency approaching 100% for 40% Tb3+. The internal and external quantum yield of the sample with Tb3+ concentration of 20% can be as high as 76% and 55%, respectively. The green phosphor, thus, shows attractive performance for near-UV-based white-light-emitting diodes applications.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article