銪摻雜矽基氮(氧)化物螢光粉之製備

Preparation of Eu-doped silicon-based (oxy)nitride phosphors

劉諺璋(Yen-Chang Liu)

指導教授 ： 林炯棟

義守大學/理工學院/材料科學與工程學系/碩士(2014年)

https://doi.org/10.6343/ISU.2014.00136

摘要

本研究以直接矽粉氮化法來製備氮(氧)化物螢光粉，包括SrSi2O2N2:Eu2+、Sr2Si5N8:Eu2+與Ca-α-SiAlON:Eu2+螢光粉，並探討其光致發光特性與顯微結構。其次，也以Pechini法製備含矽粉之前驅物粉體，在N2-H2氣氛中於1300-1550℃下進行氮化。探討碳含量、添加助熔劑、氮化溫度、矽粉的大小(<44μm、1~5μm、100nm)與矽源(Si:TEOS=2:8、5:5、7:3、9:1)的比例對於螢光粉體發光性質與顯微結構的影響。
結果顯示，以直接矽粉氮化法來製備SrSi2O2N2:Eu與Sr2Si5N8:Eu，在1450℃氮化，以370nm之UV光激發下可得到在531nm有最強放射強度；而SrSi2O2N2:Eu經高溫1500℃氮化後會轉變成Sr2Si5N8:Eu，在450nm之UV激發光下可得到在592nm有最強放射強度。
與直接矽粉氮化法比較，Pechini法製備的SrSi2O2N2:Eu，最大發光強度為矽源為Si:TEOS=7:3，Eu的摻雜量0.5 mol%(與直接矽粉氮化法一樣)。從X光繞射儀分析的結果發現，隨著氮化溫度的上升SrSi2O2N2相的結晶度就越高。以掃描式電子顯微鏡觀察其微觀結構，發現在螢光粉中隨著氮化溫度升至1400℃可以發現粉體形貌呈現塊狀物團聚在一起，在高倍率下可以發現團聚為片狀或長條型堆疊起來。另外，也對碳含量進行探討，當以700℃且持溫1小時進行除碳，發現放射強度下降。另外，從EDS結果發現除碳前後碳含量並沒有明顯改變。經由直接矽粉氮化法與Pechinin法皆可得到SrSi2O2N2相，而本研究成功以Pechini法製備與直接矽粉氮化法相同成分SrSi2O2N2:Eu與Sr2Si5N8:Eu螢光粉。
而以直接矽粉氮化法製備Ca-α-SiAlON:Eu前驅物，經1550℃高溫氮化持溫8小時後，在370nm之UV光激發下可得到在552nm有最強放射強度；而Pechini法製備Ca-α-SiAlON:Eu矽源為(Si:TEOS=9:1)，經高溫氮化後，前驅物粉體會氣化溶化，經370nm之UV光激發下可得到在429nm有最強放射強度。
當使用Pechini法且矽源為(Si:TEOS)製備SrSi2O2N2:Eu、Sr2Si5N8:Eu與Ca-α-SiAlON:Eu螢光粉經高溫氮化後，皆可在坩堝內發現有纖維副產物的產生，經X光繞射儀分析的結果為Si3N4結晶相，以掃描式電子顯微鏡觀察，其微觀結構為光滑、凹凸、扁平、長方條形等不同形態，結構沒有一致性的，另外，也有觀察到大小為1μm顆粒，從EDS結果發現纖維與顆粒的成份都是由Si、N與O所組成。
在熱衰減(Thermal decay)方面，以直接矽粉氮化法製備SrSi2O2N2:Eu在180℃放射強度降至83.5%(<44μm矽粉)、87%(1~5μm矽粉)；而以Pechini法製備者放射強度降至84%(Si:TEOS=5:5)、80.1%(Si:TEOS=7:3)，兩者都有很好的熱穩定性，當溫度降回60℃後，放射強度能接近升溫所測得值。Sr2Si5N8:Eu其放射強度降至94%。而Ca-α-SiAlON:Eu放射強度則降至92%。

關鍵字

直接矽粉氮化法 ； 檸檬酸法 ； 碳熱還原氮化法

並列摘要

In this study, the direct method to prepare silicon nitride powder nitrogen (oxygen) nitride phosphors, including SrSi2O2N2: Eu2 +, Sr2Si5N8: Eu2 + and Ca-α-SiAlON: Eu2 + phosphor, and to explore its photoluminescence properties and microstructure structure. Secondly, also Pechini precursor powders were prepared containing powder of silicon, nitrided in N2-H2 atmosphere at 1300-1550 ℃ for. Explore the carbon content, add flux, nitriding temperature, the size of the silicon powder (<44μm, 1 ~ 5μm, 100nm) and silicon source (Si: TEOS = 2: 8,5: 5,7: 3,9: 1) the proportion of fluorescent powder for luminescent properties and microstructure effects.
The results showed that the direct method to prepare silicon nitride powder SrSi2O2N2: Eu and Sr2Si5N8: Eu, nitrided at 1450 ℃ to 370nm excitation of UV light at 531nm strongest available radiation intensity; while SrSi2O2N2: Eu high temperature 1500 ℃ will be transformed into a post-nitriding Sr2Si5N8: Eu, the 450nm UV light excitation at 592nm strongest available radiation intensity.
Silicon nitride powder compared with the direct method, prepared by Pechini legal SrSi2O2N2: Eu, the maximum luminous intensity of the silicon source for Si: TEOS = 7: 3, Eu doping amount of 0.5 mol% (with the direct method, like silicon nitride powder) . From the results of X-ray diffraction analysis found that the degree of crystallinity as the nitriding temperature rise SrSi2O2N2 phase is higher. Scanning electron microscope to observe the microscopic structure found in fluorescent powder with nitriding temperature rose to 1400 ℃ can be found lumps of powder morphology presented reunion together, can be found at high magnification flake or reunion long bar stacked. In addition, the carbon content also discuss when to 700 ℃ and holding temperature for 1 hour in addition to carbon, found that the radiation intensity decreased. Further, in addition to carbon from the EDS results found after the carbon content did not change significantly. Silicon nitride powder by direct method and Pechinin law Jieke get SrSi2O2N2 phase, while the success of this study were prepared with the same ingredients Pechini direct silicon nitride powder method SrSi2O2N2: Eu and Sr2Si5N8: Eu phosphors.
And to prepare for direct silicon nitride powder legal Ca-α-SiAlON: Eu precursor after, by 1550 ℃ high temperature nitride holding temperature 8 hours in UV light at 552nm 370nm excitation available strongest radiation intensity; while Pechini France Preparation of Ca-α-SiAlON: Eu as a source of silicon (Si: TEOS = 9: 1), after the high temperature nitriding, vaporized precursor powder dissolves appreciate, the excitation of 370nm UV light available in the 429nm emission intensity of the strongest .
When using the silicon source and the Pechini method (Si: TEOS) Preparation of SrSi2O2N2: Eu, Sr2Si5N8: Eu and Ca-α-SiAlON: Eu phosphor at high temperature nitriding, can produce fibrous byproducts found in the crucible the results were analyzed by X-ray diffraction for Si3N4 crystalline phase, scanning electron microscopy, the microscopic structure of smooth, convex, flat, rectangular strip of different forms, there is no consistency in the structure, in addition, there are also observed the particle size of 1μm, and found from the EDS and the particle components are made of fiber Si, N and O composition.
In the thermal decay (Thermal decay), the direct silicon nitride powder prepared SrSi2O2N2: Eu emission intensity at 180 ℃ fell 83.5% (<44μm silica powder), 87% (1 ~ 5μm silicon powder); Pechini law and order Preparation of radiation intensity dropped by 84% (Si: TEOS = 5: 5), 80.1% (Si: TEOS = 7: 3), both have good thermal stability, when the temperature drops back to 60 ℃, radiation strength can be closer to the value of the measured temperature. Sr2Si5N8: Eu its radiation intensity dropped 94%. The Ca-α-SiAlON: Eu radiation intensity is reduced to 92%.

並列關鍵字

Direct silicon nitridation ； Carbothermal reduction nitridation ； Pechini method ； SrSi2O2N2:Eu2+ ； Sr2Si5N8: Eu2+ ； Ca-α-SiAlON: Eu2+ ； Si3N4

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