【作者】 刘岩；

【导师】 金钦汉； 周建光；

【作者基本信息】 吉林大学 ， 分析化学， 2008， 博士

【摘要】 半导体纳米晶体(又称量子点,Quantum dot,简称QD)由于其独特的光学和电学性质,在光电转换、生命科学等领域备受广大科研工作者的关注,就其光致发光性质来说,比一些有机染料更适合生物标记。目前生物学上应用的半导体纳米晶体大多来自有机相合成,该方法工艺较成熟,纳米晶体质量好。但是制备条件苛刻、步骤繁琐、成本高、毒性大,稳定性差。相比之下,水相合成方法简单、毒性小、成本低、重复性好,并且从根本上克服了在水溶液中溶解度和稳定性的问题,具有非常大的潜在应用价值。如何提高水相合成半导体纳米晶体的质量,降低制备成本和毒性,与有机物或无机物复合,实现其荧光信号的放大,并最终应用于生命科学的研究是本论文研究的初衷和目标。本论文采用多种合成方法提高CdTe纳米晶体的质量,形成了一系列绿色、快速、节能、重复性好的合成体系。成功利用微波、超声波、微波—超声波技术、微波—水热技术制备高质量的CdTe纳米晶体,纳米晶体的荧光光谱覆盖范围广,覆盖了从可见光到近红外(500~830nm),量子产率(≤80%)可以与有机相合成的纳米晶体相媲美,并且将晶体生长时间缩短了两个数量级(≤55秒)。首次发现了化学试剂诱导半导体纳米晶体生长的现象,开发出常温常压下水相合成CdTe纳米晶体的新方法,突破了低温下(≤100℃)无法生长高质量纳米晶体的瓶颈,并且该方法的重现性非常好,可以实现大批量制备,值得指出的是在纳米晶体的生长过程中,其荧光发射光谱几乎完全对称(拟合度超过99%),并且没有出现明显的“散焦”现象,显著地区别于其他方法合成出的纳米晶体。我们还将制备的纳米晶体与无机硅复合,得到了纳米尺度的荧光复合晶体和微球,实现了荧光信号的富集,还可以自行设计具有不同荧光颜色的硅玻璃。最后我们将CdTe纳米晶体用于莱姆病螺旋体微生物的活体标记,潜在指纹的显现等。更多还原

【Abstract】 Due to the unique size-dependent optical and electronic properties, high quality semiconductor nanocrystals （NCs） have widely applied in the fields of optoelectronic conversion, immune sensor and, especially, biological imaging. According to the practical requirements, these NCs need to be improved in some properties or construction. In this paper, we had synthesized high quality CdTe NCs in water by some special methods, such as microwave-asistant, ultrasonic wave-assistant, ultrasonic-microwave-assistant, or microwave- hydrothermal. And a new green synthesis way of CdTe NCs was developed. In this way, the growth of NCs was accelerated by one reagent instead of energy. We also received the composites of CdTe NCs and SiO₂ by different methods. Finally, the CdTe NCs and CdTe/SiO₂ were applied to the microorganism imaging and latent fingerprint detection.Firstly, high quality CdTe NCs was synthesized by microwave-, ultrasonic wave-, ultrasonic-microwave-, microwave-hydrothermal- assistant procedures. In these methods, not only the quantum yield was improved greatly （max. ⁸0%）, but also the spectra of fluorescence emission covered the region from visible to near infrared （500⁸30nm）. It only took less than 55 seconds to synthesize NCs, which saved a great deal of time （72 hours in other methods） and energy. Moreover, it was shown that there was some effect on growth of CdTe NCs that was not reported before when using different mode of microwave instruments. For instance, fluorescence emission of CdTe NCs would split when a multimode microwave instruments is used.Secondly, a new chemical reagent other than energy was found to accelerate the growth of semiconductor nanocrystals （cadmium telluride）, which was applied to the synthesis of high quality CdTe nanocrystals at room temperature and under ambient conditions for several hours. Under the mild conditions the mercapto-stabilizers were not destroyed, and the CdTe nanocrystals particle sizes with narrow and uniform distribution over the largest possible range was guaranteed. CdTe nanocrystals synthesized in this way had very good spectral properties. For example, the highest photoluminescence quantum yield up to 60% was obtained.Thirdly, the composites of CdTe NCs and SiO₂ were prepared by immersed self-assembled, in-situ methods and reverse microemulsion, respectively. These methods had their own merits. The immersed self-assembled means was so simple that CdTe NCs and MCM-41 were mixed together without any pretreatments. In reverse microemulsion, the size of silica nanoparticles of CdTe/SiO₂ was uniform and tunable. Moreover, we could disperse CdTe NCs into glass through sol-gel processing and a devised luminescent-glass was obtained.Finally, we had succeeded to detect the living Borrelia burgdorferi of Lyme disease by its photoluminescence image of microorganism. Since the CdTe NCs could form a photoluminescent nanocomposite with amino acid of fingerprints, a feasible and rapid detection procedure of latent fingerprints adapted well to collection of fingerprints in the location of a crime. We also studied on four medicines including Caffein, Berberine Hydrochloride, Cefalexin and Chloramphenicol, the spectra of fluorescence emission of the composites of these medicines with the CdTe NCs were affected differently.更多还原