本文選題：納米顆粒 + 去極化光譜�。� 參考：《中北大學(xué)》2015年碩士論文

【摘要】：納米顆粒由于其微小的尺寸，決定了它異于塊體材料的特殊性質(zhì)。納米材料已經(jīng)在材料、醫(yī)學(xué)、能源、工業(yè)、電子、環(huán)境等領(lǐng)域發(fā)揮了其巨大的作用，推動(dòng)了產(chǎn)業(yè)化發(fā)展進(jìn)程，方便和改善了人們的日常生活。目前，對(duì)納米材料的制備、特性以及表面等離子體共振、表面增強(qiáng)拉曼散射、量子尺寸效應(yīng)、宏觀量子隧道效應(yīng)、介電限域效應(yīng)等物理特性的理論研究已經(jīng)比較成熟。其中納米粉體材料的生產(chǎn)已經(jīng)初具規(guī)模，并且應(yīng)用在了納米制劑、納米微電子等領(lǐng)域。但是，納米顆粒的去極化效應(yīng)是近幾年才開(kāi)始研究的特性，對(duì)此方面的研究還不是很完善。 為了研究其去極化光譜，，了解它與等離子共振吸收光譜的聯(lián)系和區(qū)別，本文建立了球形納米顆粒的去極化場(chǎng)模型，詳細(xì)推導(dǎo)了球形納米顆粒的去極化場(chǎng)公式。由于去極化公式中與介電常數(shù)有很大關(guān)系，因此對(duì)與普通磁性介質(zhì)不同的金屬的介電常數(shù)以及核殼結(jié)構(gòu)的復(fù)合納米顆粒的介電常數(shù)進(jìn)行了討論。以球形金、銀、金-銀復(fù)合納米顆粒以及核殼結(jié)構(gòu)的金銀復(fù)合納米顆粒為研究對(duì)象，采用matlab軟件編程模擬了它們?cè)诰鶆蛏⑸鋱?chǎng)中的去極化行為，測(cè)量了其去極化光學(xué)吸收光譜。并且討論了金屬納米顆粒半徑、外部介質(zhì)、光照強(qiáng)度以及顆粒的核殼比等因素對(duì)其光譜的影響。 研究結(jié)果表明，純金、純銀以及金銀復(fù)合、金芯-銀殼復(fù)合納米顆粒去極化光譜都具有單峰的特征。在不同能量光照下，其介電常數(shù)是不同的，所以其去極化光譜也是變化的。但是金銀復(fù)合納米顆粒以及金芯-銀殼復(fù)合納米顆粒的峰值總是介于純金和純銀納米顆粒去極化峰值之間。去極化場(chǎng)的相對(duì)透射光強(qiáng)度會(huì)隨著粒子尺寸的增加而紅移，也會(huì)隨著外部介質(zhì)的改變，即介電常數(shù)的增加而紅移，并且粒子尺寸越大、外部介質(zhì)介電常數(shù)越大，相對(duì)透射光強(qiáng)度也越大。對(duì)于金屬?gòu)?fù)合納米顆粒，去極化峰還會(huì)隨著復(fù)合材料中金銀組分或者核殼比值的改變而發(fā)生近乎線性的紅移或藍(lán)移。究其原因，都是由于去極化場(chǎng)的存在改變了金屬表面等離子體共振的情況。 這說(shuō)明可以通過(guò)控制入射光的能量、納米顆粒半徑、外部介質(zhì)、金銀的組分或者核殼比來(lái)可控的改變金屬納米顆粒的去極化光譜，以實(shí)現(xiàn)其在醫(yī)學(xué)造影成像方面更有選擇性的應(yīng)用。
[Abstract]:Because of its small size, nanoparticles are different from the special properties of bulk materials. Nanomaterials have played an important role in the fields of materials, medicine, energy, industry, electronics, environment and so on. At present, the preparation, properties, surface plasmon resonance, surface-enhanced Raman scattering, quantum size effect, macroscopic quantum tunneling effect, dielectric limiting effect and other physical properties of nanocrystalline materials have been well studied. The production of nano-powder materials has begun to take shape, and has been applied in nano-preparation, nano-microelectronics and other fields. However, the depolarization effect of nanoparticles is only studied in recent years, and the research on this aspect is not perfect. In order to study the depolarization spectrum and understand the relation and difference between the depolarization spectrum and the plasmon resonance absorption spectrum, the depolarization field model of spherical nanoparticles is established, and the depolarization field formula of spherical nanoparticles is deduced in detail. Because the formula of depolarization is related to the dielectric constant, the dielectric constant of the metal and the composite nanoparticles with core-shell structure are discussed. The depolarization behavior of spherical gold, silver, gold-silver composite nanoparticles and core-shell structure gold-silver composite nanoparticles were simulated by matlab software, and their depolarization optical absorption spectra were measured. The effects of the radius of metal nanoparticles, the external medium, the illumination intensity and the core-shell ratio of the particles on their spectra were discussed. The results show that the depolarization spectra of pure gold, pure silver, gold-silver and gold core-silver shell composite nanoparticles have the characteristics of single peak. Under different energy illumination, the dielectric constant is different, so the depolarization spectrum is also changed. However, the peak values of gold and silver composite nanoparticles and gold core-silver shell composite nanoparticles are always between the depolarization peaks of pure gold and pure silver nanoparticles. The relative transmitted light intensity of the depolarization field will shift red with the increase of particle size and with the change of external medium, that is, the increase of dielectric constant, and the larger the particle size, the greater the dielectric constant of external medium. The greater the relative intensity of transmitted light is. For the metal composite nanoparticles, the depolarization peak also shows a nearly linear redshift or blue shift with the change of the composition of gold and silver or the core-shell ratio. The reason is that the depolarization field changes the metal surface plasmon resonance. This means that the depolarization spectrum of metal nanoparticles can be controlled by controlling the energy of incident light, the radius of nanoparticles, the external media, the composition of gold and silver, or the ratio of core to shell. In order to achieve a more selective application in medical imaging.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.1

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