A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermol...A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermolurninescenee properties and afterglow proper- ties of the phosphors were characterized systematically using X-ray diffraction （XRD）, luminescence spectrophotometer, microcom- puter thermoluminescence dosimeter and single photon counter, respectively. Under 280 nm excitation, the broadband emissions of Eu2＋ ions were observed at 445 nm （blue） due to the 4f7→4f65d transition. It was demonstrated that there existed the self-reduction of the Eu3＋ to Eu2＋ ions in this special halide-phosphate matrix in air condition. The addition of Gd3＋ ions obviously enhanced the after- glow properties of the single doped Eu2＋ ions in the halide-phosphate phosphors. And the content of the fluoride anions also had sig- nificant influence on the afterglow properties. All results indicated that Srs （PO4）3 FxCI1-x：Eu2＋,Gd3＋ might be potential phosphors for long lasting phosphorescence （LLP） materials.展开更多
A series of red phosphors Ca10Li （PO4）7：Eu3＋ were synthesized by high temperature solid-state reaction method. Their luminescence properties were characterized by means of photoluminescence excitation and emission...A series of red phosphors Ca10Li （PO4）7：Eu3＋ were synthesized by high temperature solid-state reaction method. Their luminescence properties were characterized by means of photoluminescence excitation and emission spectra,CIE chromaticity and quantum efficiency. Results indicated that the phosphors could be effectively excited by the near ultraviolet （NUV） light （393 nm）. The main emission peaks of the phosphor were ascribed to the transition 5D0–7F2 （613 and 617 nm） of Eu3＋ ion when samples were excited by 393 nm. The CIE chromaticity （x,y） of Ca9.9Li （PO4）7：0.10Eu3＋ was x=0.638,y=0.361 and the quantum efficiency of this phosphor was 75% excited by 393 nm. Therefore,this phosphor could be a promising red component for the applications in white LEDs.展开更多
A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal...A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal structure and luminescence properties were characterized and analyzed systematically by using relevant instruments.The Ca5(PO4)2SiO4:Sm^3+phosphor shows an orange-red emission peaking at600 nm under the excitation of 403 nm and the optimal doping concentration of Sm^3+is determined to be 0.08,The critical distance of Ca5(PO4)2SiO4:0.08 Sm^3+is calculated to be 1.849 nm and concentration quenching mechanism of the Sm^3+in Ca5(PO4)2SiO4 host is ascribed to energy transfer between nearestneighbor activators.The decay time of Ca5(PO4)2 SiO4:0,08 Sm^3+is determined to be 1.1957 ms.In addition,the effect of temperature on the emission intensity was also studied,72.4%of the initial intensity is still preserved at 250℃,better thermal stability compared to commercial phosphor YAG:Ce^3+indicates that Ca5(PO4)2SiO4:0.08 Sm^3+has excellent thermal stability and active energy is deduced to be 0.130 eV.All the results demonstrate that orange-red emitting Ca5(PO4)2SiO4:0.08 Sm3+phosphor exhibits good luminescent properties.Owing to the excellent thermal quenching luminescence property,Ca5(PO4)2SiO4:0.08 Sm^3+phosphor can be applied in n-UV white light emitting diodes and serve as the warm part of white light.展开更多
基金Project supported by Cooperation Project in Industry, Education and Research of Guangdong Province and Ministry of Education of China （2012B09110044）, and the Guangdong Provincial Natural Science Foundation of China （9151009001000052 ）
文摘A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermolurninescenee properties and afterglow proper- ties of the phosphors were characterized systematically using X-ray diffraction （XRD）, luminescence spectrophotometer, microcom- puter thermoluminescence dosimeter and single photon counter, respectively. Under 280 nm excitation, the broadband emissions of Eu2＋ ions were observed at 445 nm （blue） due to the 4f7→4f65d transition. It was demonstrated that there existed the self-reduction of the Eu3＋ to Eu2＋ ions in this special halide-phosphate matrix in air condition. The addition of Gd3＋ ions obviously enhanced the after- glow properties of the single doped Eu2＋ ions in the halide-phosphate phosphors. And the content of the fluoride anions also had sig- nificant influence on the afterglow properties. All results indicated that Srs （PO4）3 FxCI1-x：Eu2＋,Gd3＋ might be potential phosphors for long lasting phosphorescence （LLP） materials.
基金Project supported by 2009 National Technical Innovation Fund for Mid and Small Size Enterprise of China (09C26214405227)2009 Huizhou Science and Technology Project of China (2009B010004008)
文摘A series of red phosphors Ca10Li （PO4）7：Eu3＋ were synthesized by high temperature solid-state reaction method. Their luminescence properties were characterized by means of photoluminescence excitation and emission spectra,CIE chromaticity and quantum efficiency. Results indicated that the phosphors could be effectively excited by the near ultraviolet （NUV） light （393 nm）. The main emission peaks of the phosphor were ascribed to the transition 5D0–7F2 （613 and 617 nm） of Eu3＋ ion when samples were excited by 393 nm. The CIE chromaticity （x,y） of Ca9.9Li （PO4）7：0.10Eu3＋ was x=0.638,y=0.361 and the quantum efficiency of this phosphor was 75% excited by 393 nm. Therefore,this phosphor could be a promising red component for the applications in white LEDs.
基金supported by the Research Foundation for Youth Scholars of Beijing Technology and Business University (QNJJ2019-06,PXM2019_014213_000007)
文摘A novel single-phase Sm^3+activated Ca5(PO4)2SiO4 phosphor was successfully fabricated via a conventional solid-state method,which can be e fficie ntly excited by near ultraviolet(n-UV)light-emitting chips.The crystal structure and luminescence properties were characterized and analyzed systematically by using relevant instruments.The Ca5(PO4)2SiO4:Sm^3+phosphor shows an orange-red emission peaking at600 nm under the excitation of 403 nm and the optimal doping concentration of Sm^3+is determined to be 0.08,The critical distance of Ca5(PO4)2SiO4:0.08 Sm^3+is calculated to be 1.849 nm and concentration quenching mechanism of the Sm^3+in Ca5(PO4)2SiO4 host is ascribed to energy transfer between nearestneighbor activators.The decay time of Ca5(PO4)2 SiO4:0,08 Sm^3+is determined to be 1.1957 ms.In addition,the effect of temperature on the emission intensity was also studied,72.4%of the initial intensity is still preserved at 250℃,better thermal stability compared to commercial phosphor YAG:Ce^3+indicates that Ca5(PO4)2SiO4:0.08 Sm^3+has excellent thermal stability and active energy is deduced to be 0.130 eV.All the results demonstrate that orange-red emitting Ca5(PO4)2SiO4:0.08 Sm3+phosphor exhibits good luminescent properties.Owing to the excellent thermal quenching luminescence property,Ca5(PO4)2SiO4:0.08 Sm^3+phosphor can be applied in n-UV white light emitting diodes and serve as the warm part of white light.
