Electron transport in a gold nanoparticle assembly structure stabilized by a physisorbed porphyrin derivative
Electron transport in a gold nanoparticle assembly structure stabilized by a physisorbed porphyrin derivative
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DOI：
10.1103/physrevb.82.205420
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发表时间：
2010-11-12
影响因子：
3.7
通讯作者：
Nakamura, Takayoshi
中科院分区：
文献类型：
--
作者：
Noda, Yuki;Noro, Shin-ichiro;Nakamura, Takayoshi
合成了经物理吸附的中-5,10,15,20-四（2-噻吩基）卟啉（2T）稳定的金纳米粒子（2T- aunp），并研究了这些膜组件的电子输运。采用紫外-可见-近红外光谱、红外光谱、拉曼光谱和(1)h -核磁共振光谱对2T在金纳米颗粒上的吸附机理进行了研究，结果表明2T与金纳米颗粒之间没有形成共价键。在温度相关的电阻率测量中，在温度降低50 K左右，观察到从热辅助跳变到efros - shklovskii型变范围跳变（ES-VRH）的交叉。在较高温度下，2T-AuNP组装结构遵循Arrhenius图（E(A)=15 meV），在每个测量点具有欧姆I-V特性。另一方面，低温下的活化能呈T（-1）曲线非线性下降，电阻的对数服从T（-1/2）定律，对应于ES-VRH机制，该机制被预测为受强库仑相互作用影响的变范围跳变机制。ES-VRH行为已经在饱和分子/金纳米颗粒组装中被观察到，并在我们的2T-AuNP组装中得到了证实。电子活性共轭分子成功地结合在纳米颗粒之间，使金纳米颗粒的电子结构与2T基团相互隔离。
Gold nanoparticles stabilized by meso-5,10,15,20-tetrakis(2-thienyl)porphyrin (2T) via physisorption (2T-AuNP) were synthesized, and the electronic transport of assemblies of these films was studied. The adsorption mechanism of 2T on gold nanoparticles was examined using UV-vis-NIR, IR, Raman, and (1)H-NMR spectroscopy, which showed no evidence of any covalent bonding between 2T and the gold nanoparticles. In temperature-dependent resistivity measurements, a crossover from thermally assisted hopping to Efros-Shklovskii-type variable-range hopping (ES-VRH) was observed around 50 K on decreasing the temperature. At higher temperatures, the 2T-AuNP assembly structure followed an Arrhenius plot (E(A)=15 meV) with ohmic I-V characteristics at each measurement point. On the other hand, the activation energy at lower temperatures decreased nonlinearly in a T(-1) plot, and the logarithm of the resistance obeyed a T(-1/2) law, corresponding to an ES-VRH mechanism, which is predicted for disordered materials as a variable-range hopping mechanism influenced by strong Coulomb interactions. ES-VRH behavior has been observed previously in saturated molecule/gold nanoparticle assemblies and was confirmed in our 2T-AuNP assembly. Electronically active conjugated molecules were successfully incorporated between the nanoparticles, keeping the electronic structure of the gold nanoparticle and 2T moieties isolated from each other.