Luminescent silicon nanoparticles capped by conductive polyaniline through the self-assembly method
Luminescent silicon nanoparticles capped by conductive polyaniline through the self-assembly method
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DOI：
10.1021/la0358926
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发表时间：
2004-03-02
期刊：
影响因子：
3.9
通讯作者：
Ruckenstein, E
中科院分区：
文献类型：
--
作者：
Li, ZF;Swihart, MT;Ruckenstein, E
本文首次利用接枝聚合技术在独立发光纳米硅表面制备了致密导电聚合物涂层。经过表面修饰后，纳米硅保持了其光致发光性和结晶性。纳米颗粒首先表面羟基化，然后与（3-溴丙基）三氯硅烷反应形成致密的溴丙基硅烷单层。这进一步与苯胺反应，取代了溴原子。然后用表面结合的苯胺分子作为接枝聚合聚苯胺（PANI）的活性位点。采用x射线光电子能谱、傅里叶变换红外能谱、x射线衍射和透射电子显微镜对聚苯胺覆盖的Si纳米颗粒的组成、结构、形态和其他物理性质进行了检测。硅烷自组装单层有效地保护了硅颗粒在碱性溶液中的光致发光猝灭和降解，而碱性溶液会迅速猝灭未保护颗粒的光致发光。聚苯胺涂层进一步增强了这种保护，即使在其不导电的祖母绿基态下也是如此。经hcl掺杂的（祖母绿盐）聚苯胺包覆的Si纳米复合材料的电导率超过10(-2)S/cm，比裸Si纳米复合材料的电导率提高了6个数量级。然而，在加入聚苯胺层后，光致发光光谱或寿命的变化可以忽略不计，这表明负责发光的载流子仍然被限制在Si纳米颗粒内。
Graft polymerization has been used, for the first time, to prepare a dense conductive polymer coating on free-standing luminescent silicon nanoparticles. The silicon nanoparticles maintained their photoluminescence and crystallinity after surface modification. The nanoparticles were first surface hydroxylated and then reacted with (3-bromopropyl)trichlorosilane to form a dense bromopropylsilane monolayer. This was further reacted with aniline, which displaced the bromine atoms. The surface-bound aniline molecules were then used as active sites for the graft polymerization of polyaniline (PANI). The composition, structure, morphology, and other physical properties of the PANI-capped Si nanoparticles were examined by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. The silane self-assembled monolayer effectively protected the silicon particles against photoluminescence quenching and degradation in basic solutions that rapidly quench the photoluminescence of unprotected particles. The PANI coating further enhanced this protection, even in its nonconducting emeraldine base state. The electrical conductivity of the HCl-doped (emeraldine salt) PANI-capped Si nanocomposite exceeded 10(-2) S/cm, which is 6 orders of magnitude higher than that of the bare Si nanoparticles. However, there was negligible change in the photoluminescence spectrum or lifetime upon addition of the PANI layer, suggesting that the charge carriers responsible for the luminescence remained confined within the Si nanoparticles.