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Sm3+-Modified (1 − x)Na0.5Bi0.5TiO3-xCaTiO3 (NBT-xCT:Sm3+) piezo-luminescent ceramic materials were synthesized to investigate the influence of CaTiO3 (CT) concentration on their photoluminescence and electrical performance. Under 480 nm irradiation, the NBT-xCT:Sm3+ samples exhibit prominent orange-red emission, with a prime emission peak centered at 597 nm. A moderate amount of CT doping in the Sm3+-modified NBT ceramics boosts both their photoluminescence and piezoelectric properties significantly, with NBT-0.04CT:Sm3+ showing the optimal performance. Furthermore, outstanding luminescence thermal stability over a temperature range of 293–473 K and superior water resistance behavior are achieved in the NBT-0.04CT:Sm3+ ceramic. These results indicate that NBT-xCT:Sm3+ piezo-luminescent ceramics show great potential applications in white LEDs, as well as novel optical-electronic multifunctional devices. [ABSTRACT FROM AUTHOR]

Luminescent temperature sensors based on photoluminescent materials have received considerable attention for their advantages of quick and noninvasive measurement. In this paper, a series of Tb3+, Eu3+ single-doped and co-doped Ca 2 Al 2 SiO 7 (CAS) phosphors were synthesized by sol-gel method. The phase purity, surface morphology, energy transfer, luminescence characteristics and temperature sensing properties of Tb3+, Eu3+ doped CAS phosphors have been studied carefully. Due to the energy transfer of Tb3+→Eu3+, CAS: Tb3+, Eu3+ phosphors demonstrate tunable luminescence under 238 nm excitation, in which the luminescence color gradually changes from purple-red to cool white, and then to warm white by continuously increasing the concentration of Tb3+ ions. The elongation of the fluorescence lifetime of Eu3+ with increasing Tb3+ ions content further confirms the energy transfer of Tb3+→Eu3+. The thermal behavior of CAS: Tb3+, Eu3+ phosphors shows enhanced luminescence intensity for 404 nm emission while suppressed luminescence intensity for 616 nm emissions with raising temperature, implying its potential in optical temperature sensing. Therefore, the temperature sensing performance is evaluated by using the fluorescence intensity ratio (I 404 nm /I 616 nm) in CAS: Tb3+, Eu3+ phosphors, showing a maximum relative sensitivity of 1.17%K−1 at 443 K. These results indicate that CAS: Tb3+, Eu3+ phosphors are promising candidates for tunable luminescence and non-contact temperature sensing. [ABSTRACT FROM AUTHOR]

Eu3+ singly-doped Ba 2 La 6 Y 2 (SiO 4) 6 O 2 phosphors with hexagonal structure have been synthesized by the high-temperature solid-state reaction method. The crystal structure of the samples was analyzed. To investigate the site occupation of Eu3+ in Ba 2 La 6 Y 2 (SiO 4) 6 O 2 , the photoluminescence behavior of the phosphor was studied systematically. The emission spectra under specific wavelength excitations and the excitation spectra by monitoring emissions at 5D 0 →7F 0 transition wavelengths indicated that Eu3+ ions have entered two distinct sites in the compound. According to the concentration-dependent photoluminescence properties, the preferential site occupation was illustrated. In addition, the temperature-dependent PL measurement results revealed the high thermal stability of the sample and its application potential as a noninvasive optical thermometer. This work may help to provide an alternative approach to study the site occupation of Eu3+ ions in other functional materials. • A new Eu3+-activated Ba 2 La 6 Y 2 (SiO 4) 6 O 2 phosphor was synthesized via solid-state method. • The site occupation of Eu3+ was investigated according to the photoluminescence properties. • The phosphor has a high thermal stability. • The synthesized sample could have application potential as a noninvasive optical thermometer. [ABSTRACT FROM AUTHOR]

A novel broadband (SrCa) 2 La(PO 4) 3 O: Eu2+ phosphor was successfully synthesized by the conventional high-temperature solid-state reaction. The samples are of phase purity demonstrated by XRD analysis. The photoluminescence properties of the (SrCa) 2 La(PO 4) 3 O: Eu2+ phosphor were investigated systematically. Under the excitation of 365 nm near-ultraviolet light, the phosphors exhibit absorption in the ultraviolet–visible spectral region of 280–420 nm and show an intense asymmetric broadband blue emission peaking at around 460 nm. The different crystallographic sites of Eu2+ in (SrCa) 2 La(PO 4) 3 O: Eu2+ phosphors have been verified via the photoluminescence properties. The concentration quenching mechanism, decay property, and thermal stability of the phosphor have been discussed in detail. The investigation results indicate that the as-prepared (SrCa) 2 La(PO 4) 3 O: Eu2+ phosphor will have application potential in near-ultraviolet pumped white light-emitting diodes. • A newly found compound (SrCa) 2 La(PO 4) 3 O was synthesized. • The emitting color of the (SrCa) 2 La(PO 4) 3 O: Eu2+ phosphor varies with Eu2+ concentration. • The synthesized sample could have application potential in NUV pumped wLEDs. [ABSTRACT FROM AUTHOR]

A series of Sr 3 La 2 (PO 4) 2 (SiO 4)O: Eu2+ phosphors were synthesized by conventional high-temperature solid-state reaction. The phase formation was confirmed by XRD analysis. The photoluminescence properties of Sr 3 La 2 (PO 4) 2 (SiO 4)O: Eu2+ phosphors were investigated systematically. The phosphors exhibit absorption in the ultraviolet–visible spectral region of 280–420 ​nm and show an intense asymmetric broadband blue emission peaking at 454 ​nm under the excitation at 365 ​nm. The concentration quenching mechanism, decay property, and thermal stability have been discussed in detail. The investigation results indicate that Sr 3 La 2 (PO 4) 2 (SiO 4)O: Eu2+ will have applications as the blue component in tricolor near-ultraviolet pumped white light-emitting diodes. The Sr 3 La 2 (PO 4) 2 (SiO 4)O: Eu2+ phosphor was reported, which shows the potential application as a blue component in tricolor n-UV pumped wLEDs. Image 1 [ABSTRACT FROM AUTHOR]