Luminescent properties of Ce and Eu doped Sr4Al14O25 phosphors

Thermochromic Luminescent Nanomaterials Based on Mn4+/Tb3+ Codoping for Temperature Imaging with Digital Cameras

“…According to the band assignment theory of Peng et al, the correlation observed for the 1000 °C sample would indicate that the excitation bands at 19683 cm −1 (∼508 nm) and at 29842 cm −1 (335 nm) can be ascribed to the Mn 4+ ion in the Al 4 position and those at 22049 cm −1 (453.5 nm) and at 29226 cm −1 (342 nm) to the Al 6 site. In accordance with the Tanabe−Sugano diagram for d 3 configuration, the minimum of 4 T 1 is localized beyond the 2 E parabola [16] [25] in the case of strong CFS approximation (namely, above 1.7), due to the fact that 2 E is t 2 3 electronic orbital derivative whereas 4 T 1 originates from t 2 2 e. The thermal evolution of the integral emission intensities of Mn 4+ ions for SAO annealed at 1000 and 1100 °C presented in Figure 2d (see also Figure S11) indicates that up to 90 °C no significant difference in the luminescence thermal stability between these two samples can be found. However, above 90 °C, faster thermal quenching was noticed for the sample annealed at 1000 °C.…”

“…The SrO–Al 2 O 3 system seems to be a proper host for TM and Ln 3+ dopant because the small difference in the ionic radii between strontium (132 and 140 pm for 6- and 8-coordinated Sr 2+ , respectively) and aluminum ions (53 and 67.5 pm for Al 3+ in tetrahedral and octahedral coordination, respectively). Among six different structures, SrAl 2 O 4 and Sr 4 Al 14 O 25 arouse big interest as bright luminescence emissions from trivalent Ln ions (especially Eu 3+ , − Ce 3+ , and Dy 3+ , ) were reported in that matrix. However, when those structures are doped with Mn 4+ ions, the difference in optical response is noticeable, that is, no emission of manganese in SrAl 2 O 4 :Mn 4+ was observed while for Sr 4 Al 14 O 25 :Mn 4+ intense red luminescence was reported.…”

Synthesis of Sr4Al14O25:Eu2+ green emitting luminescent nano-pigment by solution combustion method

“…Compared to conventional lighting devices, these diodes have some advantages, including low applied voltage, high power efficiency and brightness and longer life [3][4][5]. Two methods have been used to generate white light.…”

“…In SrO-Al 2 O 3 system, there are six known phosphor hosts, namely Sr 4 Al 14 O 25 [1], SrAl 2 O 4 [2], Sr 2 Al 6 O 11 [4,7,8], SrAl 12 O 19 [1,4,7,8], Sr 3 Al 2 O 6 [4,8], and SrAl 4 O 7 [8].…”

Persistent UV phosphors for application in photo catalysis

“…Decay properties of strontium aluminates improve with Al/Sr ratios and B 2 O 3 addition [11,12]; Ce doped Sr 4 Al 14 O 25 shows a UV emission at 400 nm [13]; B 2 O 3 works as a flux by consuming the intermediate phases in the sintering process and also increases the depth of the traps in the ceramic. Improvements in brightness and persistence were further achieved by doping ions like Mg 2+ , Zn 2+ , K + and Na + , because this reduces the charge defects induced by substitution of the trivalent rare-earth ions into Sr 2+ sites within the aluminates [14].…”