Investigation on the spin filtering properties of the organic molecules through single molecule conductivity measurement

成功搭建并测试了MCBJ（mechanically controlled break-junction）单分子电导和有机自由基自旋过滤特性测试平台。与初始阶段相比，在仪器设置上进行了实质性的改进，以实现有机分子的单分子电导，其比金属原子的电导小几个数量级。对仪器的结构和操作程序进行了改进，以减少振动和电噪声，并引入压电元件进行精确的结距控制。为了更好的再现性，还修改了结制造方法。溶液池和底座也安装到仪器上，以允许用于电化学门控的溶液状态测量。用对苯二硫醇作为参考检查仪器的性能，并且MCBJ仪器能够再现所报告的电导。我们将于来年进一步优化仪器的操作速度，以进行统计分析及研究有机自由基物种的实际单分子电导及自旋过滤性质。

MCBJ (mechanically controlled break-junction) as a platform for measuring single molecule conductance and testing spin filtering properties of organic radical species was successfully built and tested. Substantial improvement in the instrumental setup compared to the preliminary stage was made to realize the single molecule conductance of organic molecule which has several order of magnitude smaller than the conductance of metal atoms. Whole the structure of the instrument and the operating program was revised to reduce vibration and electrical noise and a piezo element was introduced to make precise junction distance control. Junction fabrication method was also revised for better reproducibility. Solution cell and the mount was also installed to the instrument to allow solution state measurement for electrochemical gating. Performance of the instrument was examined with p-benzenedithiol as reference and the MCBJ instrument was able to reproduce the reported conductance. Further optimization on the operating speed of the instrument for statistical analysis and investigation on the actual single molecule conductance and spin filtering properties of organic radical species will be held in subsequent year.