Local electrical properties of thin films of the polymer PTB7 are studied by conductive atomic force microscopy (C-AFM). Non-uniform nanoscale current distribution in the neat PTB7 film is revealed and connected with the existence of ordered PTB7 crystallites. The shape of local I-V curves is explained by the presence of space charge limited current. We modify an existing semi-empirical model for estimation of the nanoscale hole mobility from our experimental C-AFM measurements. The procedure of nanoscale charge mobility estimation was described and applied to the PTB7 films. The calculated average C-AFM hole mobility is in good agreement with macroscopic values reported for this material. Mapping of nanoscale hole mobility was achieved using the described procedure. Local mobility values, influenced by nanoscale structure, vary more than two times in value and have a root-mean-square value 0.22 × 10-8 m2/(Vs), which is almost 20% from average hole mobility.

中文翻译：

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半导体聚合物薄膜中的纳米级迁移率映射

通过导电原子力显微镜 (C-AFM) 研究聚合物 PTB7 薄膜的局部电学特性。揭示了纯 PTB7 薄膜中的非均匀纳米级电流分布，这与有序 PTB7 微晶的存在有关。局部 IV 曲线的形状可以通过空间电荷限制电流的存在来解释。我们修改了现有的半经验模型，用于从我们的实验 C-AFM 测量中估计纳米级空穴迁移率。描述了纳米级电荷迁移率估计的过程并将其应用于 PTB7 薄膜。计算的平均 C-AFM 空穴迁移率与该材料报道的宏观值非常一致。使用所描述的程序实现了纳米级空穴迁移率的映射。受纳米级结构影响的局部迁移率值，