本文選題：納米材料　切入點：NaGdF_4　出處：《北京交通大學》2017年碩士論文

【摘要】：稀土上轉(zhuǎn)換發(fā)光納米材料,基于其多光子過程、能量傳遞等機制,是一種能夠?qū)崿F(xiàn)低能量光子轉(zhuǎn)化為高能量光子的反Stokes發(fā)光材料。稀土上轉(zhuǎn)換發(fā)光納米材料相比于之前傳統(tǒng)發(fā)光材料,擁有良好的光學穩(wěn)定性、化學穩(wěn)定性以及發(fā)光譜發(fā)射峰窄和長壽命的優(yōu)勢,已成為當前發(fā)光學領(lǐng)域研究的重點和熱點。目前,稀土上轉(zhuǎn)換納米材料亟待解決的問題包括:(1)納米材料形貌、晶體結(jié)構(gòu)的調(diào)控;(2)納米晶體相結(jié)構(gòu)不改變的情況下,實現(xiàn)納米材料上轉(zhuǎn)換發(fā)光優(yōu)化的手段;(3)探索稀土摻雜上轉(zhuǎn)換發(fā)光納米晶體粒徑的調(diào)控,以實現(xiàn)生物醫(yī)學檢測領(lǐng)域的應(yīng)用。針對上述問題,我們創(chuàng)造性的利用優(yōu)化型溶劑熱法,制備出粒徑一致、形貌可控、分散性強、上轉(zhuǎn)換發(fā)光強度高的上轉(zhuǎn)換發(fā)光納米材料。并且深入研究了異質(zhì)離子摻雜對納米材料形貌、粒徑的調(diào)控以及光學特性的優(yōu)化。本論文取得的主要成果如下:(1)首次通過異質(zhì)離子Mg2+的摻雜,實現(xiàn)上轉(zhuǎn)換納米晶體NaGdF4:Yb3+,Er3+晶體結(jié)構(gòu)、納米材料形貌的調(diào)控,并對不等價離子摻雜的機理進行深入分析。結(jié)果表明,隨著異質(zhì)離子Mg2+摻雜的濃度逐漸增大,晶體由于晶格晶面間距減小發(fā)生微小的緊縮,當摻雜濃度高達60mol%時,達到了極限,晶體內(nèi)部開始膨脹。與此同時,隨著異質(zhì)離子Mg2+摻雜濃度的變化,上轉(zhuǎn)換納米材料基質(zhì)晶體NaGdF4:Yb3+,Er3+的形貌逐漸由雜亂的六方相納米小球和納米棒混合形態(tài)變成形貌一致、可調(diào)控的六方相納米盤,形貌發(fā)生了十分明顯的變化。(2)系統(tǒng)研究了異質(zhì)離子Mg2+摻雜對上轉(zhuǎn)換發(fā)光納米材料NaGdF4:Yb3+,Er3+發(fā)光特性的影響,并對異質(zhì)離子Mg2+摻雜后上轉(zhuǎn)換發(fā)光強度優(yōu)化的機理進行了深入的闡述。結(jié)果表明,上轉(zhuǎn)換發(fā)光強度隨著異質(zhì)離子Mg2+摻雜濃度增加而逐漸增強,并且在Mg2+摻雜濃度為60mol%時達到最強,當摻雜濃度過高時造成濃度猝滅。因此在一定濃度范圍內(nèi),Mg2+摻雜有利于上轉(zhuǎn)換熒光發(fā)射。而異質(zhì)離子Mg2+摻雜引起上轉(zhuǎn)換發(fā)光強度增強的主要原因是晶體場的對稱性降低,導致電子內(nèi)4f-4f躍遷幾率增加,從而增強了上轉(zhuǎn)換發(fā)光強度。(3)首次利用優(yōu)化型溶劑熱法合成出稀土離子共摻雜的一維類鈣鈦礦納米材料NaMgF3:Yb3+,Er3+,Gd3+。同時探究了異質(zhì)離子Gd3+的摻雜對于類鈣鈦礦納米材料粒徑、形貌和發(fā)光的影響。結(jié)果表明,隨著異質(zhì)離子Gd3+摻雜濃度的增加,納米顆粒的粒徑和形貌發(fā)生較大的變化,同時上轉(zhuǎn)化發(fā)光強度也得到了相對應(yīng)的提高。
[Abstract]:Rare earth up-converted luminescent nanomaterials are based on their multiphoton processes, energy transfer and other mechanisms. It is a kind of inverse Stokes luminescent material which can realize the conversion of low energy photons to high energy photons. Compared with traditional luminescent materials, rare earth up-conversion luminescent nanomaterials have good optical stability. The chemical stability and the advantages of narrow emission peak and long lifetime have become the focus and hotspot in the field of optical field. At present, the problems of rare earth up-conversion nanomaterials include the morphology of the nano-materials. Under the condition that the phase structure of nanocrystalline is not changed, the way to optimize the upconversion luminescence of nanomaterials is to explore the control of the particle size of rare-earth doped up-conversion luminescent nanocrystals. In order to realize the application in the field of biomedical detection. In view of the above problems, we creatively used the optimized solvothermal method to prepare the particles with uniform particle size, controllable morphology and strong dispersibility. Up-conversion luminescent nanomaterials with high up-conversion luminescence intensity. The main results obtained in this thesis are as follows: 1) for the first time, the up-conversion nanocrystalline NaGdF4:Yb3 er _ 3 crystal structure and the morphology of nanomaterials can be controlled by doping heterogeneous ion Mg2. The mechanism of nonequivalent ion doping is analyzed in depth. The results show that with the increasing of the doping concentration of heterogeneous ion Mg2, there is a slight contraction due to the decrease of lattice plane spacing, and the limit is reached when the doping concentration is as high as 60 mol%. At the same time, with the change of Mg2 doping concentration, the morphology of up-conversion nanocrystalline NaGdF4:Yb3 er _ 3 gradually changed from the mixed morphology of hexagonal nanospheres and nanorods to the same morphology. The influence of heteroionic Mg2 doping on the luminescence characteristics of up-conversion luminescent nanocrystalline NaGdF4:Yb3 (er _ 3) was systematically investigated. The mechanism of up-conversion luminescence intensity optimization after Mg2 doping is discussed. The results show that the up-conversion luminescence intensity increases with the increase of Mg2 doping concentration. When the concentration of Mg2 was 60 mol%, the highest concentration was obtained. When the doping concentration is too high, the concentration is quenched. Therefore, doping Mg2 in a certain concentration range is advantageous to up-conversion fluorescence emission. The main reason for the enhancement of up-conversion luminescence intensity caused by Mg2 doping is that the symmetry of crystal field decreases. Leading to an increase in the probability of the 4f-4f transition in the electron, Thus, the upconversion luminescence intensity was enhanced.) the one-dimensional perovskite-like nanomaterial NaMgF3:Yb3 er _ 3 / Gd _ 3 was synthesized by optimized solvothermal method for the first time. At the same time, the effect of heterogeneous ion Gd3 doping on the particle size of perovskite-like nanomaterials was investigated. The results showed that the particle size and morphology of the nanoparticles changed greatly with the increase of the doping concentration of heterogeneous ions Gd3, and the up-conversion luminescence intensity was also increased correspondingly.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O482.31

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本文編號：1655051