Temperature dependent DC current-voltage (I-V) down to 50 K and field-dependent AC impedance measurements were carried out to study the electric field and temperature dependence of charge carrier mobility in Poly(3-octylthiophene) based metal/polymer/metal device structures of different charge carrier concentrations. In highly doped device, a negative field-dependent mobility (NFDM) which vanishes below 150 K was observed whereas a positive field-dependent mobility (PFDM) was observed in moderately doped devices. The observed NFDM is attributed to the low energetic disorder and high positional disorder in the highly doped devices. With further lowering of carrier concentration, charge carrier mobility first decreases with the increase in applied field attaining a minimum value and then increases with the applied field. At higher temperatures $(\mathrm{T}>150K)$, all the three devices show thermally-activated process and activation energy increases with lowering the charge carrier concentrations indicating that doping level plays important role in thermally activated transport mechanism. However, in lower temperature $(\mathrm{T}<100K)$, activation energy is almost independent of doping level suggesting that injected carrier plays an important role in the lower temperature region. Data from AC impedance measurement also supports the field-dependent mobility model of conduction mechanism in the devices. Analysis of the AC impedance data of the three devices reveals that the equivalent circuit of highly and moderately doped devices is different from that of the low carrier concentration device. The presence of highly energetic disorder in low carrier concentration devices is also confirmed from AC impedance analysis.

进行了低至 50 K 的温度相关直流电流电压 (IV) 和场相关交流阻抗测量，以研究基于聚（3-辛基噻吩）的金属/聚合物/金属中电荷载流子迁移率的电场和温度依赖性不同载流子浓度的器件结构。在高掺杂器件中，观察到负场相关迁移率 (NFDM) 在 150 K 以下消失，而在中度掺杂器件中观察到正场相关迁移率 (PFDM)。观察到的 NFDM 归因于高掺杂器件中的低能量无序和高位置无序。随着载流子浓度的进一步降低，载流子迁移率首先随着外加电场的增加而降低，达到最小值，然后随着外加电场的增加而增加。在较高温度下$(\mathrm{吨}>150钾)$，所有三个器件都显示出热激活过程，激活能随着电荷载流子浓度的降低而增加，表明掺杂水平在热激活传输机制中起着重要作用。然而，在较低的温度$(\mathrm{吨}<100钾)$，活化能几乎与掺杂水平无关，这表明注入的载流子在较低温度区域起着重要作用。来自交流阻抗测量的数据还支持器件中传导机制的场相关迁移率模型。对三种器件的交流阻抗数据的分析表明，高、中掺杂器件的等效电路与低载流子浓度器件的等效电路不同。交流阻抗分析也证实了低载流子浓度器件中存在高能无序。