摘要：本文采用再沉淀法制备C60纳米粒子，并提出了利用光腐蚀调控C60纳米粒子粒径的方法。通过动态光散射粒径分析、扫描电子显微镜、透射电子显微镜、红外光谱、紫外-可见光谱等表征手段，研究了光腐蚀C60纳米粒子的粒径变化和部分机理。这些结果表明：在氧气存在的条件下，C60纳米粒子的粒径随着光照时间的增加而减小，其吸光度也随着光照时间的增加而减小；在无光照或无氧条件下，C60纳米粒子粒径不发生改变，因此光照和氧气是发生反应的必不可少的两个条件。基于上述结果和红外光谱的分析，我们认为C60纳米粒子粒径的改变是由于C60在光致激发下发生能量传递产生单重态氧（1O2），1O2具有较强的氧化性，能够氧化C60，通过多次氧化反应，可能破坏C60的结构，甚至将其氧化至CO2，从而使粒径变小。此外，本文还以三甲胺（TMA）、硫醇作为电子给体，研究了C60在光电转换方面的应用，结果表明在光照条件下，产生的C60励起子在C60与电解液表面发生电荷分离（产生电子和空穴），其中产生的电子进入ITO的导带，而产生的空穴接受TMA或硫醇给出的电子，产生光阳极电流。同时受上述结果的启发，以甲基蓝为模型，进一步研究了C60在光催化方面的应用。结果表明C60在光照条件下，能够不断氧化甲基蓝，使其逐步分解。这可能与C60作为1O2敏化剂，在光照下产生具有较强氧化能力的1O2有关；另外，根据C60光电转换的实验结果，光照下产生的C60励起子能够在C60与电解液表面发生电荷分离，产生的空穴也可能直接氧化甲基蓝。
关键词：C60纳米粒子；再沉淀法；光腐蚀；光电转换；光催化
Abstract: In this research, C60 nanoparticles were first synthesized by the reprecipitation method, and we proposed a smart approach to control the size of C60 nanoparticles by photoetching. Through dynamic light scattering instrument, scanning electron microscope, transmission electron microscope, fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, etc., we studied size change of the C60 nanoparticles under light irradiation and discussed part of the mechanism of it. These results indicated that in the presence of oxygen, size of the C60 nanoparticles decreased with increasing irradiation time, and absorbance of the C60 nanoparticle suspension decreased, too; in the absence of light or oxygen, their size did not change, so light illumination and oxygen were necessary for the reaction. Based on the results above and the infrared spectrum analysis, the size change of the C60 nanoparticles was probably due to the energy transfer from photoexcited C60 to triplet oxygen and subsequently generated singlet oxygen (1O2), which had relatively strong oxidation power and could oxidize C60 or even oxidized it to CO2. In addition, we discussed the application of the C60 nanoparticles to photoelectric conversion by using trimethylamine (TMA) or thiol as electron donor. The results indicated that the photoinduced C60 exciton achieved charge separation at C60/electrolyte interface (generated electrons and holes); then the electrons were injected into conduction band of ITO, and the holes received electrons from trimethylamine or thiol; finally, the photoanodic current was generated. Inspired by the mentioned results above, we further studied the photocatalyst application of the C60 nanoparticles by photodegradation of methyl blue. The decomposition of methyl blue might relate to energy transfer generated 1O2 and/or charge separation generated holes by C60 under light irradiation.
Key words： C60 nanoparticles, reprecipitation, photoetching, photoelectric conversion, photocatalysis
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