Site preference and defect engineering of a highly efficient blue-emitting phosphor Sr₂SiO₄:Ce³⁺/K⁺ toward thermally enhanced luminescence

Abstract

Blue-emitting phosphor is one of the trichromatic phosphors essential for the development of near-ultraviolet (nUV) pumped phosphor-converted white light-emitting diodes (pc-WLEDs). Efficiency and thermal stability are two critical factors for...

White-emitting orthosilicate phosphor α-Sr2SiO4:Ce3+/Eu2+/K+: a bimodal temperature sensor with excellent optical thermometric sensitivity

“…The spectral change was observed by varying the excitation wavelength from 320 nm to 365 nm, suggesting that there are two luminescence centers of Eu 2+ in the phosphor, which correspond to the 10-fold coordinated Sr1 and 9-fold coordinated Sr2. 25 While applying Gaussian decomposition to the PL spectrum excited at 365 nm, two peaks at 20 789 cm −1 (481 nm) and 18 179 cm −1 (550 nm) can be well fitted (Fig. 2b).…”

“…Besides, our recent study illustrated that Ce 3+ activated α′-Sr 2 SiO 4 has thermally enhanced luminescence under the excitation of n-UV light. 25 In order to investigate the tunability of photoluminescence of α′-Sr 2 SiO 4 based phosphors co-activated by Ce 3+ /Eu 2+ , we adopted a fixed Eu 2+ concentration (0.01) and a range of Ce 3+ doping concentrations ( x , 0.01–0.035) in this study.…”

“…Very recently, we reported a phosphor α-Sr 2 SiO 4 :Ce 3+ ,K + which exhibited an abnormal thermal quenching phenom-enon, namely, its emission intensity gradually increases while raising the temperature and retains 120% of its room-temperature peak intensity at 250 °C. 25 We therefore initiated this work by further introducing Eu 2+ into the host α-Sr 2 SiO 4 , and investigated the thermal behavior of luminescence of phosphors to test our hypothesis. As a result, we developed a temperature-sensing phosphor with high sensitivity and precision by co-doping Ce 3+ and Eu 2+ into α-Sr 2 SiO 4 although there is a slight overlap in the spectral peaks.…”

Optical enhancement of highly efficient organic–inorganic oxyfluoride red phosphors via the cation co-doping strategy

“…As can be seen from Fig. 5d, the [N(CH 3 ) 4 ] 3 MoO 3 F 3 : Mn 4+ phosphor has significant thermal quenching behavior, and according to Arrhenius eqn (9), the activation energy (E a ) required for quenching the formation temperature of the sample is 0.27 eV: [50][51][52]…”

“…Therefore, we believe that reducing the number of quenching centers (defects and impurities) or implementing new phase-building strategies will be necessary. Based on current research, unlike most ion-doped materials, 9,10 for Mn 4+ -doped phosphors, whether the matrix ions undergo equivalent substitution to form a solid solution system or non-equivalent substitution for charge compensation, the introduction of these ions can reduce the quenching centers and thus improve the optical properties of phosphors to varying degrees. For instance, Hong et al reported the formation of a solid solution through ion co-doping, which effectively enhanced the luminescence intensity, thermal stability and hydrophobic stability of the Na 2 SiF 6 :Mn 4+ phosphor.…”