3-巯基异丁酸衍生物对碲化镉量子点水相合成的影响

Effects of Derivatives of 3-Mercaptoisobutyric Acid on the Aqueous Synthesis of CdTe Quantum Dots

为探索适宜制备粒径分布窄、荧光量子产率高、发光区域在红光至近红外光区段的量子点的巯基酸的条件,我们研究了三类3-巯基异丁酸(MIBA)衍生物在以亚碲酸钠为碲源的水相法水热制备CdTe量子点中的影响.这三类衍生物包括设计合成的主链亲水性衍生物3-巯基异丁酰甘氨酸(MIBGly)、3-巯基异丁酰-3-氨基丙酸(MIBAPA)和3-巯基异丁酰天冬氨酸(MIBAsp),支链亲水性衍生物N-乙酰基半胱氨酸(ACys)和支链疏水性衍生物3-巯基-2-甲基丁酸(MMBA)和3-巯基-2,2-二甲基丙酸(MDMPA).以这三类MIBA衍生物为修饰剂时,CdTe量子点均能够保持MIBA体系较窄的荧光半峰宽.采用亲水性的MIBA衍生物(MIBGly、MIBAPA、MIBAsp和ACys)比采用疏水性的MIBA衍生物(MMBA和MDMPA)更有利于制备发射波长较长的量子点.采用支链亲水性的MIBA衍生物((ACys)比采用主链亲水性的MIBA衍生物(MIBGly、MIBAPA和MIBAsp)更容易获得高荧光量子产率的量子点.

Mercapto acids can affect the obtaining CdTe quantum dots （QDs） with narrow size distribution and high fluorescent quantum yield （QY） that emit in the red to near-infrared region. To study their effects on CdTe QDs, three types of derivatives of 3-mercaptoisobutyric acid （MIBA） were designed and synthesized： hydrophilic side-chain derivative N-acetylcysteine （ACys）, hydrophobic side-chain derivatives 3-mercapto-2-methylbutyric acid （MMBA） and 3-mercapto-2,2-dimethylpropanoic acid （MDMPA）, and hydrophilic main-chain derivatives 3-mercaptoisobutoyl-3-aminopropanoic acid （MIBAPA）, 3-mercaptoisobutoylglycine （MIBGly） and 3-mercaptoisobutoylaspartic acid （MIBAsp）. To evaluate the effects of these MIBA derivatives on the properties of CdTe QDs, they were used as capping agents during hydrothermal synthesis of the QDs with sodium tellurite as the tellurium source. The effects of the mercapto acids were revealed by comparing the growth rate, and full width at half-maximum （FWHM） of the fluorescent peak of CdTe QDs capped with different mercapto acids. All three types of MIBA derivatives gave CdTe QDs with relatively narrow FWHM, similar to MIBA. The hydrophilic MIBA derivatives （ACys, MIBGly, MIBAPA, and MIBAsp） produced CdTe QDs with longer emission wavelength than those from hydrophobic derivatives. Hydrophilic side-chain MIBA, derivative ACys gave CdTe QDs with stronger fluorescence.