Using density functional theory in combination with Green's functional formalism we study the quantum transport through molecular junctions containing pyrimidine units characterized by a permanent dipole moment. The presence of the pyrimidine rings results in the enhanced current through the junctions for both polarities of the applied voltage. In addition, these systems show clear current rectification due to the polar nature of the molecules. The effect of dihedral angle between phenyl and pyrimidine rings on the current rectification is also studied. The obtained results are explained in terms of charge localization in the system as revealed in the transmission eigenvalues analysis. The obtained results can be useful in understanding the role of polar self-assembled monolayers in interface engineering.

使用密度泛函理论与格林的泛函形式论相结合，我们研究了通过具有永久偶极矩特征的嘧啶单元的分子结的量子输运。对于施加的电压的两个极性，嘧啶环的存在导致通过结的电流增加。另外，由于分子的极性，这些系统显示出清晰的电流整流。还研究了苯基和嘧啶环之间的二面角对电流整流的影响。如传输特征值分析所揭示的那样，根据系统中的电荷定位来解释获得的结果。获得的结果可能有助于理解极性自组装单分子层在界面工程中的作用。