ZnS基納米晶的制備及其性能研究
發(fā)布時(shí)間：2018-07-26 18:19
【摘要】：本文利用熱溶液注入法和水熱法合成了 ZnS,ZnS:Eu~(3+),ZnSexS1x納米晶,制備方法操作簡單,成本低,相對綠色環(huán)保,合成產(chǎn)物具有較好的熒光性能。利用第一性原理計(jì)算了材料的電子結(jié)構(gòu),并利用XRD,TEM,SEM,熒光光譜,UV-vis吸收光譜等對所得納米晶進(jìn)行了表征。具體內(nèi)容如下:(1)構(gòu)建了立方相ZnS的1×1×2的超胞,并在此基礎(chǔ)上,通過添加和刪減原子,建立了具有不同缺陷的ZnS空間模型,利用第一性原理計(jì)算了不同缺陷的形成能和電子結(jié)構(gòu),分析了不同缺陷對能帶結(jié)構(gòu)和態(tài)密度的影響。采用熱溶液注入法合成了不同Zn/S比例的ZnS納米晶。XRD衍射分析表明所得產(chǎn)物均為立方閃鋅礦結(jié)構(gòu),TEM圖顯示所得納米晶的顆粒近似球形,分散性良好,HRTEM圖可以看出明顯的晶格條紋,不同Zn/S比制備的ZnS納米顆粒粒徑在3nm到7nm之間。樣品的發(fā)射光譜的主峰位置在418nm、433nm、468nm和500nm,分別對應(yīng)著四個(gè)缺陷能級躍遷。(2)構(gòu)建了立方相ZnS的2×2×2的超胞,其中,分別用Eu原子取代其中的一個(gè)Zn原子和兩個(gè)Zn原子,利用第一性原理計(jì)算了摻雜Eu的ZnS的電子結(jié)構(gòu),分析了不同摻雜濃度對能帶結(jié)構(gòu)和態(tài)密度的影響。采用熱溶液注入的方法合成了不同摻雜濃度的ZnS:Eu~(3+)納米晶,XRD圖譜顯示納米晶為立方閃鋅礦結(jié)構(gòu)。TEM表明顆粒近似球形,隨著摻雜濃度的增加,粒徑逐漸增大。HRTEM可見明顯晶格條紋。EDS圖譜中觀察到了 Eu元素的能量峰。測試了納米晶的熒光光譜,發(fā)射光譜在595nm、621nm和701nm處出現(xiàn)了 Eu~(3+)的特征峰,其中位于621nm處的發(fā)射峰強(qiáng)度最大。激發(fā)光譜中位于395nm處的激發(fā)峰強(qiáng)度最大,隨著摻雜濃度的增加,色坐標(biāo)向白色區(qū)域靠近。(3)在立方相 ZnS 超胞的基礎(chǔ)上,構(gòu)建了 ZnSe_xS_(1-x)(x=0.20,0.33,0.50,0.67,0.80,1.00)空間模型,用第一性原理計(jì)算了其電子結(jié)構(gòu),分析了不同x值對其能帶和態(tài)密度的影響。利用熱溶液注入法合成了 ZnSe_xS_(1-x)納米晶,隨著x值的增加,XRD衍射峰向小角度方向偏移,顆粒粒徑從3.74nm逐漸增大到了 4.33nm。測試了納米晶的熒光光譜,在440nm激發(fā)下,發(fā)射峰從518nm紅移到了 544nm;監(jiān)測528nm,得到的激發(fā)光譜的激發(fā)峰從423nm紅移到了 475nm。(4)利用水熱法合成了 ZnS微晶,并且改變了制備過程中前軀體的Zn/S比例和水醇比,得到了具有不同發(fā)光性能的ZnS微晶,XRD顯示納米晶為立方閃鋅礦結(jié)構(gòu),發(fā)射光譜出現(xiàn)了由硫空位和鋅空位缺陷引起的兩個(gè)發(fā)射峰,分別位于483nm和586nm,隨著Zn/S比例的變化,兩個(gè)發(fā)射峰的相對強(qiáng)度會(huì)隨之發(fā)生變化。當(dāng)水醇比為1:1時(shí),發(fā)射峰強(qiáng)度最大,半高寬最小。
[Abstract]:In this paper, ZnS: ZnSexS1x nanocrystalline was synthesized by hot solution implantation and hydrothermal method. The preparation method is simple, low cost, relatively green and environmentally friendly. The synthesized product has better fluorescence properties. The electronic structure of the material was calculated by first principles. The nanocrystalline was characterized by XRDX Tem SEM, fluorescence spectra and UV-vis absorption spectra. The main contents are as follows: (1) 1 脳 1 脳 2 supercell of cubic ZnS is constructed. On this basis, by adding and deleting atoms, the ZnS space model with different defects is established, and the formation energy and electronic structure of different defects are calculated by first principle. The effects of different defects on the band structure and density of states are analyzed. The ZnS nanocrystals with different Zn/S ratios were synthesized by hot solution injection method. The results showed that the nanocrystalline particles were almost spherical, and the lattice stripes were obvious in the well-dispersed ZnS images. The size of ZnS nanoparticles prepared with different Zn/S ratios ranged from 3nm to 7nm. The main peaks of the emission spectra of the samples are at 418 nm, 433 nm, 468 nm and 500 nm, respectively, corresponding to the transition of four defect levels. (2) the supercell of 2 脳 2 脳 2 in cubic phase ZnS is constructed, in which one Zn atom and two Zn atoms are replaced by EU atom, respectively. The electronic structure of ZnS doped with EU was calculated by first principle, and the influence of doping concentration on the band structure and density of states was analyzed. The XRD patterns of ZnS _ (3) nanocrystalline with different doping concentrations were synthesized by hot solution injection. The results show that the nanocrystalline is cubic sphalerite structure. The energy peak of EU element was observed in the lattice stripe. EDS diagram. The fluorescence spectra of nanocrystals were measured. The emission spectra showed the characteristic peaks of EU3 at 621nm and 701nm, and the emission peaks located at 621nm were the most intense. The intensity of excitation peak located at 395nm is the largest in the excitation spectrum. With the increase of doping concentration, the chromatic coordinate is closer to the white region. (3) based on the cubic phase ZnS supercell, the spatial model of ZnSexS1-x (x0.200.33O0.500.500.50,0.670.800.801.00) has been constructed, and its electronic structure has been calculated by the first principle. The effects of different x values on the energy band and density of states are analyzed. ZnS _ XS _ (1-x) nanocrystals were synthesized by hot solution injection method. With the increase of x value, the diffraction peak shifted to small angle, and the particle size gradually increased from 3.74nm to 4.33 nm. The fluorescence spectra of nanocrystals were measured. The emission peak shifted from 518nm red to 544 nm under 440nm excitation, and the excitation peak from 423nm red to 475 nm was obtained by monitoring 528 nm. (4) ZnS microcrystals were synthesized by hydrothermal method. By changing the Zn/S ratio of precursor and the ratio of water to alcohol, the nanocrystalline ZnS with different luminescent properties was obtained, which shows that the nanocrystalline is cubic sphalerite structure. There are two emission peaks caused by sulfur vacancy and zinc vacancy defect in the emission spectrum, which are located at 483nm and 586 nm, respectively. With the change of Zn/S ratio, the relative intensity of the two emission peaks will change. When the ratio of water to alcohol is 1:1, the emission peak intensity is the largest and the half maximum width is the smallest.
【學(xué)位授予單位】：河北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1
本文編號：2146894
[Abstract]:In this paper, ZnS: ZnSexS1x nanocrystalline was synthesized by hot solution implantation and hydrothermal method. The preparation method is simple, low cost, relatively green and environmentally friendly. The synthesized product has better fluorescence properties. The electronic structure of the material was calculated by first principles. The nanocrystalline was characterized by XRDX Tem SEM, fluorescence spectra and UV-vis absorption spectra. The main contents are as follows: (1) 1 脳 1 脳 2 supercell of cubic ZnS is constructed. On this basis, by adding and deleting atoms, the ZnS space model with different defects is established, and the formation energy and electronic structure of different defects are calculated by first principle. The effects of different defects on the band structure and density of states are analyzed. The ZnS nanocrystals with different Zn/S ratios were synthesized by hot solution injection method. The results showed that the nanocrystalline particles were almost spherical, and the lattice stripes were obvious in the well-dispersed ZnS images. The size of ZnS nanoparticles prepared with different Zn/S ratios ranged from 3nm to 7nm. The main peaks of the emission spectra of the samples are at 418 nm, 433 nm, 468 nm and 500 nm, respectively, corresponding to the transition of four defect levels. (2) the supercell of 2 脳 2 脳 2 in cubic phase ZnS is constructed, in which one Zn atom and two Zn atoms are replaced by EU atom, respectively. The electronic structure of ZnS doped with EU was calculated by first principle, and the influence of doping concentration on the band structure and density of states was analyzed. The XRD patterns of ZnS _ (3) nanocrystalline with different doping concentrations were synthesized by hot solution injection. The results show that the nanocrystalline is cubic sphalerite structure. The energy peak of EU element was observed in the lattice stripe. EDS diagram. The fluorescence spectra of nanocrystals were measured. The emission spectra showed the characteristic peaks of EU3 at 621nm and 701nm, and the emission peaks located at 621nm were the most intense. The intensity of excitation peak located at 395nm is the largest in the excitation spectrum. With the increase of doping concentration, the chromatic coordinate is closer to the white region. (3) based on the cubic phase ZnS supercell, the spatial model of ZnSexS1-x (x0.200.33O0.500.500.50,0.670.800.801.00) has been constructed, and its electronic structure has been calculated by the first principle. The effects of different x values on the energy band and density of states are analyzed. ZnS _ XS _ (1-x) nanocrystals were synthesized by hot solution injection method. With the increase of x value, the diffraction peak shifted to small angle, and the particle size gradually increased from 3.74nm to 4.33 nm. The fluorescence spectra of nanocrystals were measured. The emission peak shifted from 518nm red to 544 nm under 440nm excitation, and the excitation peak from 423nm red to 475 nm was obtained by monitoring 528 nm. (4) ZnS microcrystals were synthesized by hydrothermal method. By changing the Zn/S ratio of precursor and the ratio of water to alcohol, the nanocrystalline ZnS with different luminescent properties was obtained, which shows that the nanocrystalline is cubic sphalerite structure. There are two emission peaks caused by sulfur vacancy and zinc vacancy defect in the emission spectrum, which are located at 483nm and 586 nm, respectively. With the change of Zn/S ratio, the relative intensity of the two emission peaks will change. When the ratio of water to alcohol is 1:1, the emission peak intensity is the largest and the half maximum width is the smallest.
【學(xué)位授予單位】：河北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TB383.1
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