碳纳米管@多酸/共轭聚合物纳米线阵列光电肖特基结及其毒品敏感机理研究

The real-time, supersensitive and contactless detection of drug vapors is of great significance to the fight against drug crimes. Our pre-research proved that polyoxometalate doped conjugated polymers film can discriminate opium and amphetamine from drugs. However, the film is not beneficial drug molecular diffusion. A high-performance Schottky junction sensor for the detection of trace drug vapors will be constructed by a conjugated polymer-assisted assembly of carbon nanotubes via a template-based method. The conjugated polymers play a role of semiconductors in the Schottky junction and can trap drug molecules by rich π-π interaction. The metallic single-walled carbon nanotube plays a role of metal in the Schottky junction with fast response and supersensitivity due to the improvement of carrier separation. The insertion of polyoxometalate that could both modulate the Schottky barrier height and widen the range of the spectrum response. Thus, a sensory array based on a single optoelectronic sensor could be built by regulating the excitation wavelength. The design may greatly increase the sensitivity and selectivity in a Schottky junction sensor. The carrier separation and the kinetics of the sensing performance will be analyzed by the Schottky model to clarify the sensing mechanism. This project will establish the research basis and provide new idea for novel portable sensor to detect drugs.

毒品气氛的实时、高灵敏、非接触式检测对打击毒品犯罪具有重要意义。前期预研发现多酸掺杂的共轭聚合物薄膜对鸦片和安非他命类毒品有特异性识别能力。但聚合物薄膜不利于分子扩散，灵敏度有限。项目拟构筑一种共轭聚合物辅助定向排列碳纳米管的肖特基结纳米线阵列传感基元，聚苯撑乙炔衍生物作为肖特基结中的半导体存在，可通过π-π相互作用吸附毒品分子；金属性单壁碳纳米管作为肖特基结中的金属存在，有效促进电子-空穴分离，从而提高灵敏度和缩短响应时间；多酸可有效调节肖特基势垒高度，并扩展传感基元的光谱响应范围，因此，通过变换激发波长，就可以由单个传感器实现传感器阵列的目的，进而实现实时、高灵敏、非接触式检测毒品气氛。同时，分析电子转移及其响应动力学，揭示肖特基结复合结构与传感器响应信号差异性放大的构效关系，阐明毒品气氛传感机理。该项目的实施为便携式毒品气氛检测仪开发奠定理论基础。

毒品气氛的实时、高灵敏、非接触式检测对打击毒品犯罪具有重要意义。聚亚苯基乙炔衍生物(PPV)具有优异的光学响应、化学稳定性、柔性和一维电子传输结构，但PPV的光致载流子分离效率低，阻碍了其实际应用。本项目从PPV形貌调控和能带结构调控入手，(1)以多孔氧化铝为模板，采用溶液润湿法构筑了一系列不同孔径的PPV纳米管阵列，并提出了PPV纳米管阵列可能的生长机理；(2)构筑了具有不同能带结构的PPV纳米管阵列碳纳米管@磷钨酸钠/PPV。其中，磷钨酸钠和单壁碳纳米管可有效提高PPV光生电子-空穴分离效率，对常见毒品呈现优异的敏感性能。这可能是由于PPV与毒品中的芳香环通过Π-Π相互作用所引起的。此外，为了达到识别不同种类毒品分子的目的，本研究创造性的通过改变激发波长，仅用一个传感芯片实现了传感阵列的目的。结合指纹图，实现了对TT(三唑仑片）、MPA（d-甲基苯丙胺盐酸盐）、CP（磷酸可待因）、MC（吗啡盐酸盐）、KM（K粉）和DC（二甲卡因）等六种毒品气氛的检测。作为拓展研究，本项目所构建的方法同样适用于爆炸物气氛检测，可实现对硝酸铵(AN)、二硝基甲苯 (DNT)、苦味酸 (PA)、对硝基甲苯 (PNT)、三过氧化三丙酮(TATP)、三硝基甲苯 (TNT)气氛的检测。