共轭高聚物中低浓度掺杂下的杂质分布研究

基于紧束缚近似，研究了一维共轭高聚物链在链呈电中性，以及链中带有正、负电荷等不同情况下低浓度掺杂对系统稳定性的影响，并采用绝热近似下的自洽计算方法得出了系统在掺杂前后发生的总能量改变。研究发现，掺杂位置对系统稳定性的影响非常明显。根据杂质分布的特点，一条共轭高聚物链一般可分为链端区、中心区和过渡区三个明显不同的区域。系统的稳定性不仅受掺杂位置，杂质势的强度及性质影响，而且还受到高聚物链的载荷状态的影响。在链端区及过渡区，杂质分布趋向于凝聚成畴，而在中心区域，杂质趋于均匀分布。该研究表明，通过对掺杂条件的控制，可以有效控制杂质在共轭高聚物中的分布状态。

Study on the impurity distribution in conjugated polymers at light doping

Based on a tight binding model, we investigate impurity effect upon the stability of neutral and negatively or positively charged 1D conjugated polymer chains. The offsets of system energy due to light doping are calculated within adiabatic approximation. We show that the doping position has significant impact upon system stability. The polymer chain can generally be divided into edge, center and transition regions in terms of impurity distribution. It is found that the static impurity distribution within a polymer chain being dominated by the strength and the sign of the impurity potential as well as whether the polymer chain is neutral or charged. Impurity distribution within the edge and the transition region is characterized by cluster and that within the center region by separation. The results of this study suggest that impurity doping in conjugated polymers can be effectively controlled by manipulating various conditions.