TY - JOUR
T1 - Phase stabilization of red-emitting olivine-type NaMgPO4:Eu2+phosphors
T2 - Via molten-phase quenching
AU - Hasegawa, Takuya
AU - Iwaki, Masato
AU - Tanaka, Ryo
AU - Kim, Sun Woog
AU - Yin, Shu
AU - Toda, Kenji
N1 - Funding Information:
This work was partly supported by some projects from NEDO, New Energy and Industrial Technology Development Organization (Rare Metal Substitute Materials Development Project Development of Technology for Reducing Tb and Eu Usage in Phosphors for Fluorescent Lamp by High-speed Material Synthesis and Evaluation), KAKENHI (Grant number 20K15106) and the Dynamic Alliance for Open Innovations Bridging Human, Environment and Materials, the Cooperative Research Program of “Network Joint Research Center for Materials and Devices”.
Publisher Copyright:
© 2020 the Partner Organisations.
PY - 2020/11/7
Y1 - 2020/11/7
N2 - An olivine-type Eu2+-activated NaMgPO4 (NMP:Eu2+) material was previously discovered as a new red-emitting oxide phosphor with a high quantum efficiency under blue light excitation; however, the use of a special and nonuniversal optical system of an arc-imaging furnace was necessary for its synthesis. To realize the synthesis of NMP:Eu2+ using a conventional tubular furnace, in this work, we employed a new synthetic strategy of rapid quenching from a high temperature, which imitates the synthesis process using the arc-imaging furnace. As a result, we succeeded in stabilizing the olivine structure in the NMP:Eu2+ phosphor. Thermogravimetric-differential thermal analysis (TG-DTA) revealed the presence of the polymorphism of glaserite (low-temperature phase) and olivine (high-temperature phase) phases in the NaMgPO4:0.025Eu2+ composition, and the stabilized region of the olivine phase was found to be around 1000 °C, which indicated that the rapid quenching process effectively acted as an olivine phase stabilizer. According to X-ray diffraction (XRD) measurements, the NMP:Eu2+ phosphor samples have the olivine structure as the main phase. Additionally, the photoluminescence (PL) intensity of the phosphor was 1.3 times that of the previous NMP:Eu2+ phosphor prepared using the arc-imaging furnace. The internal quantum efficiency of the NMP:Eu2+ phosphor was found to be 72.3%, which is the highest among the known Eu2+-activated red-emitting oxide phosphors. Moreover, other properties relevant to light-emitting diode (LED) phosphors, such as the chemical composition, chemical state of Eu, particle morphology, PL lifetime, thermal quenching properties, humidity resistance and electroluminescence (EL) properties of a fabricated phosphor-converted (pc)-LED, were investigated in detail. This journal is
AB - An olivine-type Eu2+-activated NaMgPO4 (NMP:Eu2+) material was previously discovered as a new red-emitting oxide phosphor with a high quantum efficiency under blue light excitation; however, the use of a special and nonuniversal optical system of an arc-imaging furnace was necessary for its synthesis. To realize the synthesis of NMP:Eu2+ using a conventional tubular furnace, in this work, we employed a new synthetic strategy of rapid quenching from a high temperature, which imitates the synthesis process using the arc-imaging furnace. As a result, we succeeded in stabilizing the olivine structure in the NMP:Eu2+ phosphor. Thermogravimetric-differential thermal analysis (TG-DTA) revealed the presence of the polymorphism of glaserite (low-temperature phase) and olivine (high-temperature phase) phases in the NaMgPO4:0.025Eu2+ composition, and the stabilized region of the olivine phase was found to be around 1000 °C, which indicated that the rapid quenching process effectively acted as an olivine phase stabilizer. According to X-ray diffraction (XRD) measurements, the NMP:Eu2+ phosphor samples have the olivine structure as the main phase. Additionally, the photoluminescence (PL) intensity of the phosphor was 1.3 times that of the previous NMP:Eu2+ phosphor prepared using the arc-imaging furnace. The internal quantum efficiency of the NMP:Eu2+ phosphor was found to be 72.3%, which is the highest among the known Eu2+-activated red-emitting oxide phosphors. Moreover, other properties relevant to light-emitting diode (LED) phosphors, such as the chemical composition, chemical state of Eu, particle morphology, PL lifetime, thermal quenching properties, humidity resistance and electroluminescence (EL) properties of a fabricated phosphor-converted (pc)-LED, were investigated in detail. This journal is
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U2 - 10.1039/d0qi00880j
DO - 10.1039/d0qi00880j
M3 - Article
AN - SCOPUS:85095112701
VL - 7
SP - 4040
EP - 4051
JO - Inorganic Chemistry Frontiers
JF - Inorganic Chemistry Frontiers
SN - 2052-1545
IS - 21
ER -