本文選題：NaYF_4　切入點(diǎn)：Y_2O_3　出處：《長(zhǎng)春工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：鑭系元素?fù)诫s的納米晶體具有獨(dú)特的光學(xué)性質(zhì),在體內(nèi)成像、太陽能電池和3D顯示等領(lǐng)域具有很多潛在的應(yīng)用,引起了學(xué)術(shù)界的廣泛關(guān)注。特別是氧化物和氟化物納米晶由于其獨(dú)特的光學(xué)性質(zhì)、高化學(xué)穩(wěn)定性和低聲子能量等特點(diǎn),常被用作納米晶的主晶格材料。同時(shí),合成的稀土納米晶與高聚物結(jié)合的復(fù)合材料將會(huì)進(jìn)一步推動(dòng)稀土納米晶的廣泛應(yīng)用。利用水熱法成功合成了YF_3納米晶、α-NaYF_4和β-NaYF_4混相納米晶及β-NaYF_4納米晶,通過在合成的氟化物納米粒子中摻入Zn~(2+)離子及改變Zn~(2+)離子濃度,實(shí)現(xiàn)了YF_3到α-NaYF_4納米晶和α-NaYF_4到β-NaYF_4納米晶的晶相轉(zhuǎn)變過程,相變主要是由于Zn~(2+)離子替代了Y~(3+)離子的晶格位點(diǎn)導(dǎo)致了電荷變化和更低的能量壁壘。同時(shí),我們也探究了不同濃度的Zn~(2+)離子摻雜對(duì)稀土摻雜氟化物納米晶上轉(zhuǎn)換發(fā)光的影響,實(shí)現(xiàn)了稀土摻雜的氟化物納米晶上轉(zhuǎn)換發(fā)光強(qiáng)度的提高。采用均相沉淀法制備了Y(OH)_3@Y(OH)_3核殼結(jié)構(gòu)微球,經(jīng)1100℃焙燒后制備出具有上轉(zhuǎn)換發(fā)光性質(zhì)的Yb~(3+)-Tm~(3+)-Gd~(3+)共摻的Y_2O_3的納米晶體,討論了Yb~(3+)-Tm~(3+)-Gd~(3+)在Y_2O_3中能量傳遞過程及殼層對(duì)發(fā)光強(qiáng)度的影響。TEM和XRD結(jié)果證明了通過焙燒后合成了Y_2O_3核殼結(jié)構(gòu)。上轉(zhuǎn)換光譜結(jié)果表明,在Yb~(3+)-Tm~(3+)-Gd~(3+)共摻體系中,核殼結(jié)構(gòu)大幅度提高了Tm~(3+)和Gd~(3+)的上轉(zhuǎn)換熒光強(qiáng)度,尤其是310 nm附近的紫外發(fā)光部分增強(qiáng)更為明顯。同時(shí),通過研究Tm~(3+)和Gd~(3+)在不同波段的發(fā)光強(qiáng)度與泵浦功率的關(guān)系探討了上轉(zhuǎn)換發(fā)光的機(jī)制。采用均相沉淀法合成了Gd(OH)_3@Gd(OH)_3核殼結(jié)構(gòu)微球,經(jīng)1100℃焙燒后制備出具有上轉(zhuǎn)換發(fā)光性質(zhì)的Yb~(3+)-Er~(3+)/Tm~(3+)共摻的Gd_2O_3的納米晶體。在980 nm激發(fā)光激發(fā)下,通過包覆同質(zhì)殼層,觀察到Gd_2O_3@Gd_2O_3納米晶中Er~(3+)(Tm~(3+))離子上轉(zhuǎn)換發(fā)光強(qiáng)度的大幅度增強(qiáng)。同時(shí),在實(shí)驗(yàn)結(jié)果的基礎(chǔ)上討論了稀土離子間能量吸收和能量傳遞過程。采用本體聚合法合成了NaYF_4/PMMA復(fù)合材料,摻雜Er~(3+)的NaYF_4納米晶均勻分布在PMMA聚合物中。稀土納米粒子的摻雜提高了PMMA復(fù)合材料的耐熱性,而復(fù)合材料透光性沒有明顯地降低。在980 nm激發(fā)光條件下,復(fù)合材料發(fā)射出明顯的綠光,同時(shí),隨著NaYF_4納米粒子摻雜含量的提高,復(fù)合材料的上轉(zhuǎn)換發(fā)光強(qiáng)度逐漸提高。
[Abstract]:Lanthanide doped nanocrystals have unique optical properties and have many potential applications in imaging in vivo, solar cells and 3D display. In particular, oxide and fluoride nanocrystals are often used as main lattice materials for nanocrystalline because of their unique optical properties, high chemical stability and low energy. The composite of rare earth nanocrystalline and polymer will further promote the wide application of rare earth nanocrystalline. YF_3 nanocrystals, 偽 -NaYF4 and 尾 -NaYF4 mixed nanocrystals and 尾 -NaYF4 nanocrystals have been successfully synthesized by hydrothermal method. By adding Zn~(2) ions into the synthesized fluoride nanoparticles and changing the concentration of Zn~(2) ions, the process of phase transition from YF_3 to 偽 -NaYF4 nanocrystals and 偽 -NaYF4 to 尾 -NaYF4 nanocrystals was realized. The phase transition is mainly due to the fact that the lattice sites of the Zn~(2) ions replace YP3) ions leading to the change of charge and lower energy barriers. We also investigated the effect of different concentrations of Zn~(2 ion doping on upconversion luminescence of rare earth doped fluoride nanocrystals. The upconversion luminescence intensity of rare earth doped fluorides nanocrystals was improved. YOHHHX 3DX O HH3 codoped Y2O3 nanocrystals were prepared by homogeneous precipitation method. The codoped Y2O3 nanocrystals were prepared by calcination at 1100 鈩，

本文編號(hào)：1643193