A nanogap-array platform for testing the optically modulated conduction of gold-octithiophene-gold junctions for molecular optoelectronics
A nanogap-array platform for testing the optically modulated conduction of gold-octithiophene-gold junctions for molecular optoelectronics
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DOI：
10.1039/c2ra21484a
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发表时间：
2012-01-01
期刊：
影响因子：
3.9
通讯作者：
Demarchi, Danilo
中科院分区：
文献类型：
--
作者：
Rattalino, Ismael;Cauda, Valentina;Demarchi, Danilo
我们研究了金-寡聚噻吩-金分子结作为一个完全定制的平台的光依赖性导电。该平台的灵活性和新奇依赖于其与外部电子板的即插即用连接，以通过电迁移诱导断裂结（EIBJ）和分子电学表征来执行八个并行纳米间隙制造。此外，辛噻吩分子被自组织合成以有效地自组装并在沉积时选择性地桥接纳米间隙电极，这可以在8个纳米间隙阵列平台上直接和并行地进行。该平台的高度便携性非常适合原位显微镜和光谱分析。特别地，我们通过将电流-电压（I-V）表征与荧光和拉曼光谱耦合来测试辛噻吩分子结的电功能性。此外，表面增强拉曼光谱（Sers）被用于第一次精确地关联的分子的位置与结的电导。电导的调制也可以通过改变光激发波长来实现。这种电转换的结揭示了在450 nm的光激发波长附近的分子传导的峰值，与光响应调制的电流在低偏压高达120%，相对于初始值在300 nm。所提出的ad-hoc平台设计使分子结成为真实的工作块，其可以与外部电路接口以服务于电子元件或传感器的功能，并且克服了传统分子接触方法（例如机械控制断开结（MCBJ）或扫描探针显微镜）的可用性、成本和便携性的限制。因此，我们表明，寡聚噻吩的光电性能可以利用分子结的形式来制造用于分子电子学的光电器件。
We studied the light dependent conduction of gold-oligothiophene-gold molecular junctions as a fully-customized platform. The flexibility and novelty of the platform relies on its plug-and-play connection to an external electronic board to perform eight parallel nanogap fabrications by Electromigration Induced Break Junction (EIBJ) and molecular electrical characterization. In addition, the octithiophene molecules are synthesized ad-hoc to efficiently self-assembly and selectively bridge the nanogap electrodes upon deposition, which can be carried out directly and in parallel on the 8 nanogap array platforms. The high portability of the platform is well suited for in-situ microscopic and spectroscopic analyses. In particular, we tested the electrical functionality of the octithiophene molecular junctions by coupling electrical current-voltage (I-V) characterization with fluorescence and Raman spectroscopies. In addition, surface-enhanced Raman spectroscopy (SERS) was used for the first time to precisely correlate the position of the molecule with the conductance of the junction. Modulation of the electrical conductance can also be achieved by varying the light excitation wavelength. Such electrical transduction of the junction revealed a peak in molecule conduction around the light excitation wavelength of 450 nm, with a photoresponsive modulation of the current at low bias voltage up to 120% with respect to the initial value at 300 nm. The proposed ad-hoc platform design makes molecular junctions real working blocks, which can be interfaced with external circuitries to serve the function of electronic components or sensors and overcome the limitations of usability, cost and portability of traditional molecular contacting methods, such as Mechanically Controlled Break Junction (MCBJ) or scanning probe microscopy. We thus demonstrate that the optoelectronic properties of oligothiophenes can be exploited in the form of molecular junctions to fabricate optoelectronic devices for molecular electronics.