胶态光子晶体在磁场、电场等外场调控下能够可逆地改变光子禁带的结构，进而改变反射峰位置、强弱乃至材料呈现的结构色，因此被广泛结合应用在显示、探测、防伪、催化、拉曼增强等研究热点中。本论文从胶态光子晶体的制备、调控和应用三点出发，进行了系统研究。研究中主要以单分散Fe₃O₄做为胶态光子晶体的基本结构单元,详细研究了如何制备、修饰磁性纳米颗粒Fe₃O₄。在构筑胶态光子晶体时候，研究了改变不同条件对于胶态光子晶体光学性能的影响，同时设计了基于胶态光子晶体的光学器件，研究了在相应领域的应用。基于Bragg定律，总结了胶态光子晶体光学变化规律，并依此调制光学器件。最后利用光子晶体的光学增强效果，实现了胶态光子晶体的功能拓展。本论文主要的研究内容和结果如下： 1)探索了合成具有亚铁磁性Fe₃O₄颗粒的溶剂热方案，颗粒粒径范围可以控制在60- 160 nm之间，再利用超声波协助的方法使颗粒表面修饰上PAA，颗粒的表面电势增强，同时PAA又兼具空间位阻作用。利用磁场调控含有磁性颗粒的溶胶，当磁场施加到181 G就可形成胶态光子晶体，反射出明亮的结构色，反射峰可从720nm蓝移到511 nm,呈现出的结构色包括红、黄、绿。该磁性溶胶存放时间可达2年以上，并且在磁场下仍然保有光子晶体光学特性。同时研究了入射光强度对于反射率影响，发现在入射角不变情况下，入射光越强，反射率越高。在该磁性溶胶基础上研制出一种磁场分布可视化探测器，通过结构色的变化，反映被测区域磁场分布情况。 2)通过改进溶剂热法，合成出由柠檬酸钠修饰的Fe₃O₄，相比前一部分内容中制备胶态光子晶体方法，所制备颗粒无需再次改性，就能够在磁场操控下形成光子晶体，制备工艺简便高效，且合成的颗粒为超顺磁性，避免了颗粒间偶极子作用团聚。研究中发现颗粒生长受到柠檬酸钠与乙酸钠加入量的影响，通过调节两者质量比，可以合成出来粒径均一，大小可控的磁性纳米颗粒。此外，发现调节乙二醇与一缩二乙二醇体积比也可以调整颗粒尺寸大小，使得粒径范围可以在50-230 nm范围内调控。再对溶胶施加外部磁场，能形成胶态光子晶体，呈现出绚丽的结构色。论文系统研究了颗粒浓度、颗粒大小、溶胶pH值等对于反射峰范围与强度的影响，发现当溶胶的颗粒浓度是10㎎/mL, pH值大于4，反射光谱范围从806 nm到449nm。同时通过不同角度测得光谱图证实了溶胶在磁场下行成了一维链状胶态光子晶体结构。 3)在前一部分内容中所制备Fe₃O₄基础上，对颗粒进行包裹修饰，获得了核壳结构的Fe₃O₄@SiO₂球形颗粒，其中SiO₂厚度可控。以Fe₃O₄@SiO₂为结构单元的光子晶体反射峰可达近红外区域，在磁场强度超过一定阙值后，反射峰位置保持不变，这是因为颗粒表面大量硅羟基使得一层溶剂化层形成在颗粒周围，显示出不同光学特性。此外， Fe₃O₄@SiO₂颗粒在水以外的极性溶剂中也有良好的分散性。为了获得能够在电场驱动下胶态光子晶体，研究了分散于碳酸丙烯酯中Fe₃O₄@SiO₂，在不施加外场，当Fe₃O₄@SiO₂体积分数超过7.8%，就能显示出结构色。通过注射体积分数10.4 %电场响应溶胶进入由ITO构建的三明治器件中，在4V以内电压驱动下形成非晶光子晶体，具有非虹彩效果和宽的可视范围。对样品表面形貌SEM进行研究，通过进行2D傅里叶变换得到了预测光谱图，与实际测得光谱图基本一致，并且发现颗粒排布具有短程有序的非晶光子晶体特征。 4)制备了具有荧光示踪效果的CQD/SiO₂/Au与Fe₃O₄@SiO₂/Au两种催化剂。首先研究了反应温度、时间对于CQD生长和荧光特性的影响。接着研究了纳米金在Fe₃O₄@SiO₂表面的形貌与紫外可见吸收光谱。然后在催化应用研究中，测得CQD/SiO₂/Au对于对硝基苯酚的催化速率达到0.00295 s⁻¹，Fe₃O₄@SiO₂/Au的催化速率达到0.02451 s⁻¹。同时，Fe₃O₄@SiO₂/Au具有拉曼增强效果，由于外加磁场作用，使得纳米颗粒有序排列后溶胶内部纳米金之间间隙和热点数量大大增加。在原有的1.27×10⁶基础上，当磁场施加到200G增强因子达到4.72×10⁶，实现了三倍的增益效果。 关键词：光子晶体；胶体；Fe₃O₄；磁场；电场；布拉格定律

 The photonic band gap of colloidal photonic crystals is reversibly changed with the magnetic field or electric field, resulting in changing the reflection peak location, reflection intensity and structural colors. It has been widely accepted in the fields of display, detection, anti-counterfeiting, catalysis and surface enhanced raman scattering. The thesis mainly studies the preparation, modulation applications of colloidal photonic crystals. The monodisperse Fe₃O₄ particles as the structural unit of colloidal photonic crystal is studied that how to prepare and modified the particles. Then, the influence of various conditions on optical properties was studied when the colloidal photonic crystals is manipulated. The corresponding optical devices is also prepared, and its applications is also studied. Based on Bragg law, the optical variation of colloidal photonic crystals is discovered and used in modulating optical devices. Finally, the photonic crystal is used to enhance optical effect for enlarging the application kinds. The main research contents and results of the thesis are as follows: 1)The ferromagnetic particles were synthesized by polyol method. The size range of particle can be controlled between 60-160 nm. Because the surface modification of the particles adopted ultrasonic wave method to adsorb PAA, the particle have higher surface potential and the steric hindrance at the same time. Then the magnetic field is used to modulate magnetic colloidal structure for forming colloidal photonic crystal, resulting in reflecting bright structure color and broad reflecting spectrum. The magnetic colloidal can be stored for over 2 years, and the optical properties of photonic crystals are still presented. At the same time, the influence of incident light intensity on the reflectivity is studied. The stronger the incident light is, the higher the reflectivity is. Finally, we developed a magnetic field distribution visualization detector, which reflects the strength and strength of the magnetic field. 2)A Fe₃O₄ superparamagnetic particles modified with sodium citrate is synthesized with a novel solvothermal method. Compared with the previous part, this preparation of colloidal photonic crystal method can be used to form photonic crystals under magnetic field control without modifying, and the preparation process is simple and efficient. The obtained particles have superparamagnetism avoiding the dipole interaction among particles. It is found that particle growth is controlled by the mass ratio of sodium citrate and sodium acetate. By adjusting the mass ratio of sodium citrate and sodium acetate, the controllable particle size and morphology can be obtained. In addition, the size of particle can be adjusted by adjusting the volume ratio of glycol and diethylene glycol. The particle size range can be controlled within 60-200 nm by combining two adjustment methods. The particles dispersed in water are applied to the external magnetic field, which can form photonic crystals and produce brilliant structural colors. The influences of particle concentration, particle size and pH value on the range and strength of the reflection are studied systematically. It is found that when the concentration of the particles is 10 ㎎/mL and the pH value is greater than 4, the reflectance spectrum ranged from 806 nm to 449 nm. It is proved that the colloid is a one-dimensional chain colloidal photonic crystal structure with measuring angle-resolved specular reflection. 3)Based on the previous preparation of Fe₃O₄, the particles were coated and modified by silicon dioxide, and the core-shell structure of Fe₃O₄@SiO₂ particles are obtained. Meanwhile, the SiO₂ thickness is controllable. When Fe₃O₄@SiO₂ is as the structure unit of the photonic crystal, the reflection peak can reach the near infrared region in magnetic field. Due to the solvation layer of particles, the magnetic strength exceeds a certain value when the reflection peak remains the same peak, which show the unique optical properties. In addition, Fe₃O₄@SiO₂ particles also have good dispersivity in polar solvents. Fe₃O₄@SiO₂ dispersed in propylene carbonate is injected between two ITOs for forming the sandwich device. The amorphous photonic crystals under voltage driver has a non-iridescent with a wide range of visual. The surface morphology of the sample was studied by SEM, and the spectrogram was obtained by 2D Fourier transform which is in accordance with the measured spectrum. It is found that the particle arrays show the short-range ordered structures of amorphous photonic crystals. 4)The fluorescent CQD/SiO₂/Au and Fe₃O₄@SiO₂/Au were prepared as catalysts. The influences of reaction temperature and time on growth and fluorescence characteristics of CQD are studied. The surface morphology and uv-visible absorption spectra of nano-gold in Fe₃O₄@SiO₂/Au are also studied. In the catalytic application study, CQD/SiO₂/Au catalytic rate was measured to be 0.00295 s⁻¹, and Fe₃O₄@SiO₂/Au was 0.02451 s⁻¹. At the same time, Fe₃O₄@SiO₂/Au has the effect of Raman enhancement, and the enhancement factor is 4.72 X 10⁶ under a magnetic field (200 G). Key Words: Photonic crystal; Colloid; Fe₃O₄; Magnetic field; Electric field; Bragg law