Alekseev A, Yedrissov A, Hedley G J, Ibraikulov O, Heiser T, Samuel I D W, Kharintsev S
National Research University "MIET", Moscow, 124498, Russia; Kazan Federal University, Kazan, 420008, Russia.
NLA, Nazarbayev University, 010000 Nur-Sultan, Kazakhstan.
Ultramicroscopy. 2020 Nov;218:113081. doi: 10.1016/j.ultramic.2020.113081. Epub 2020 Jul 22.
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 m/(Vs), which is almost 20% from average hole mobility.
通过导电原子力显微镜（C-AFM）研究了聚合物PTB7薄膜的局部电学性质。揭示了纯PTB7薄膜中纳米级电流分布不均匀的现象，并将其与有序PTB7微晶的存在联系起来。局部I-V曲线的形状由空间电荷限制电流的存在来解释。我们根据实验C-AFM测量结果修改了现有的用于估算纳米级空穴迁移率的半经验模型。描述了纳米级电荷迁移率的估算过程，并将其应用于PTB7薄膜。计算得到的平均C-AFM空穴迁移率与该材料报道的宏观值吻合良好。使用所述方法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在数值上变化超过两倍，均方根值为0.22×10 m/(Vs)，几乎是平均空穴迁移率的20%。
