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结合密度泛函理论和非平衡格林函数方法计算了溶液酸碱性对低聚苯亚乙炔基分子结电输运性质的影响,此低聚苯亚乙炔基分子中两个不同位置的H原子被氨基和羧基取代.通过质子化和去质子化模拟酸性溶液和碱性溶液对分子结构的影响.计算结果表明:中性环境下分子器件具有良好的导电性和微弱的整流效应;碱性溶液中羧基去质子化后,分子器件电流值增长近一倍,但整流效应变化不明显;酸性溶液中氨基质子化后,分子器件正向偏压导电性能略微降低,但整流方向发生明显反转,且与中性环境下的情况相比,整流比提高了近三倍.提出了一种利用化学手段控制分子结导电能力和整流性能的方法.
The effects of acidity and basicity of the solution on the transport properties of the oligo (phenylenevinylene) molecules were calculated by using the density functional theory and the non-equilibrium Green’s function method. The H atoms at two different positions in the oligo-phenylenevinylene molecule were Amino and carboxyl groups.The effects of acidic solution and alkaline solution on the molecular structure were simulated by protonation and deprotonation.The results show that the molecular devices have good conductivity and weak rectification effect in neutral environment, After deprotonation of carboxyl group, the current value of the molecular device nearly doubled, but the rectification effect did not change obviously. After the protonation of amino group in acidic solution, the forward biased conductivity of the molecular device decreased slightly, but the rectification direction reversed obviously, and Compared with the neutral environment, the rectification ratio has nearly tripled, and a method to control the conductivity and rectification performance of molecular junction by chemical means is proposed.