發(fā)布時間：2018-01-02 17:45

  本文關(guān)鍵詞：高溫處理對稀土摻雜納米顆粒上轉(zhuǎn)換發(fā)光性能的影響　出處：《鄭州大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 上轉(zhuǎn)換 β-NaYF_4:Yb~(3+) Er~(3+)/Na LuF_4 核-殼 高溫煅燒 發(fā)光性能

【摘要】：稀土摻雜納米材料的上轉(zhuǎn)換發(fā)光是指吸收兩個或者多個低能量的光子發(fā)射出一個高能量的光子,是一種反斯托克斯發(fā)光。稀土摻雜上轉(zhuǎn)換納米材料具有反斯托克斯位移大、發(fā)射譜帶尖銳、發(fā)光壽命長、光穩(wěn)定性好、自發(fā)熒光低、靈敏度高等特點,使其在生物成像、疾病的診斷與治療、固體激光、平板顯示器、太陽能電池等方面具有潛在的應(yīng)用價值。至今,在稀土摻雜上轉(zhuǎn)換納米材料合成及應(yīng)用方面,研究者已經(jīng)做了大量的工作。但是,較低的發(fā)光效率嚴(yán)重制約了稀土摻雜上轉(zhuǎn)換納米材料的發(fā)展。許多研究者已經(jīng)嘗試多種提高上轉(zhuǎn)換納米材料發(fā)光效率的方法,例如,基質(zhì)材料的選擇、金屬離子摻雜、表面鈍化、增大敏化寬帶、表面等離子體耦合、光子晶體工程等。但是,稀土摻雜上轉(zhuǎn)換納米材料的發(fā)光效率仍然很低。而摻雜稀土離子濃度相同的情況下,塊體材料的發(fā)光效率卻相對較高。因此,尋找塊體材料與納米材料發(fā)光效率差異的內(nèi)在原因具有重要的意義。相比于稀土摻雜上轉(zhuǎn)換納米材料,塊體材料通常在高溫條件下制備,那么,高溫是否是決定發(fā)光效率的關(guān)鍵因素呢?但納米材料在高溫煅燒下,將會團(tuán)聚,并最終形成塊體材料,這是實驗面臨的最大障礙。在本文中,為了實現(xiàn)高溫煅燒后,納米顆粒能保持原有的形貌和尺寸而不發(fā)生團(tuán)聚,我們通過在納米顆粒周圍均勻包覆一定厚度的SiO2,對納米顆粒進(jìn)行保護(hù),高溫煅燒后,再將SiO2選擇性的除去,得到保持原有的形貌和尺寸的納米顆粒,并且,研究不同階段納米顆粒的上轉(zhuǎn)換發(fā)光性能。最后,探索影響納米顆粒上轉(zhuǎn)換發(fā)光性能的主要原因。具體研究內(nèi)容如下:(1)采用甲醇輔助有機相合成法合成NaYF_4:Yb~(3+),Er~(3+)納米顆粒,并且系統(tǒng)地探究反應(yīng)時間、反應(yīng)溫度、ODE/OA比例對NaYF_4:Yb~(3+),Er~(3+)納米顆粒的形貌和尺寸的影響,得到類球型的β-NaYF_4:Yb~(3+),Er~(3+)納米顆粒(25.5±0.7 nm)。(2)以類球型的β-Na YF_4:Yb~(3+),Er~(3+)納米顆粒(25.5±0.7 nm)為核,在核的表面包裹一層β-NaLuF_4。通過改變犧牲劑α-NaLuF_4納米顆粒的加入量,合成不同尺寸的β-NaYF_4:Yb~(3+),Er~(3+)/NaLu F_4核-殼納米顆粒,并且探究β-NaLuF_4殼層對上轉(zhuǎn)換納米顆粒發(fā)光性能的影響。結(jié)果表明,各向同性的β-NaLu F_4殼層(5.5 nm)能顯著地減少β-NaYF_4:Yb~(3+),Er~(3+)納米顆粒的表面猝滅效應(yīng),提高β-NaYF_4:Yb~(3+),Er~(3+)/Na LuF_4核-殼納米顆粒的上轉(zhuǎn)換發(fā)光性能。(3)以β-NaYF_4:Yb~(3+),Er~(3+)/NaLuF_4核-殼納米顆粒(34.5±0.6 nm)為核,采用微乳液法在核的周圍均勻地包覆一層SiO2,獲得β-NaYF_4:Yb~(3+),Er~(3+)/NaLuF_4/SiO2核-殼-殼納米顆粒,然后,對其進(jìn)行高溫煅燒,再使用HF選擇性地將煅燒后納米顆粒外層的SiO2刻蝕掉,重新得到NaYF_4:Yb~(3+),Er~(3+)/Na LuF_4納米顆粒。最后,對高溫處理前后β-NaYF_4:Yb~(3+),Er~(3+)/Na LuF_4納米顆粒的發(fā)光性能進(jìn)行研究。結(jié)果表明,經(jīng)過400℃煅燒后,重新獲得的β-NaYF_4:Yb~(3+),Er~(3+)/NaLuF_4納米顆粒的形貌、尺寸及物相都沒有變化,但是,在刻蝕SiO2的過程中,β-NaYF_4:Yb~(3+),Er~(3+)/Na LuF_4納米顆粒的表面又引入新的表面缺陷,所以,其發(fā)光強度沒有提高,這也說明表面缺陷是影響其發(fā)光性能的重要因素之一。
[Abstract]:Rare earth doped nano materials on Upconversion Luminescence absorption refers to two or more low energy photons emitted a high energy photon, is a kind of anti Stokes luminescence. Rare earth doped up conversion nano material with anti Stokes displacement, sharp luminescence emission bands, long service life, good light stability, autofluorescence low, high sensitivity characteristics, the biological imaging, diagnosis and treatment of diseases, the solid state laser, flat panel display, has potential application in solar cell and so on. So far, conversion nano material synthesis and application in rare earth doped, researchers have done a lot of work. However, low luminous efficiency seriously restricts the development of rare earth doped upconversion nanomaterials. Many researchers have tried a variety of improved conversion method, the luminous efficiency of nano materials such as matrix materials, metal ion Doping, surface passivation, increasing sensitization broadband, surface plasmon coupling, photonic crystal engineering. However, rare earth doped luminescent nano material conversion efficiency is still very low. And the concentration of rare earth ions under the same luminous efficiency of bulk materials is relatively high. Therefore, it is very important to find the inner reason of the luminous efficiency the difference of bulk materials and nano materials. Compared to the rare earth doped up conversion nano material, block material is usually under the condition of high temperature preparation, then, whether the temperature is a key factor determining the luminous efficiency? But the nanometer material under the high temperature calcination will reunite, and ultimately the formation of bulk materials, this is the biggest obstacle the face. In this paper, in order to achieve after high-temperature calcination, nanoparticles can maintain the morphology and size of the original without aggregation, we through the nano particles evenly coated around certain The thickness of SiO2, for the protection of the nano particles, after high temperature calcination, then SiO2 selective removal of particles, maintain the morphology and size of the original and the conversion luminescence properties of nano particles in different stages. Finally, explore the main reasons affecting conversion properties of nanoparticles. The specific contents are as follows: (1) the methanol assisted organic phase synthesis method for synthesis of NaYF_4:Yb~ (3+), Er~ (3+) nanoparticles, and to probe into the reaction time, reaction temperature, the ratio of ODE/OA to NaYF_4:Yb~ (3+), Er~ (3+) affect the morphology and size of nano particles, get the ball type beta -NaYF_4:Yb~ (3+). Er~ (3+) nanoparticles (25.5 + 0.7 nm). (2) the ball type beta -Na YF_4:Yb~ (3+), Er~ (3+) nanoparticles (25.5 + 0.7 nm) as the core, adding the nuclear surface coated with a layer of beta -NaLuF_4. by changing the sacrificial agent alpha -NaLuF_4 nanoparticles. No synthesis 鍚屽昂瀵哥殑尾-NaYF_4:Yb~(3+),Er~(3+)/NaLu F_4鏍，

本文編號：1370286