Patel Shrayesh N, Glaudell Anne M, Kiefer David, Chabinyc Michael L
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
ACS Macro Lett. 2016 Mar 15;5(3):268-272. doi: 10.1021/acsmacrolett.5b00887. Epub 2016 Feb 5.
We demonstrate how processing methods affect the thermoelectric properties of thin films of a high mobility semiconducting polymer, PBTTT. Two doping methods were compared: vapor deposition of (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane (FTS) or immersion in a solvent containing 4-ethylbenzenesulfonic acid (EBSA). Thermally annealed, thin films doped by FTS deposited from vapor yield a high Seebeck coefficient (α) at high electronic conductivity (σ) and, in turn, a large power factor (PF = ασ) of ∼100 μW m K. The FTS-doped films yield α values that are a factor of 2 higher than the EBSA-doped films at comparable high value of σ. A detailed analysis of X-ray scattering experiments indicates that perturbations in the local structure from either dopant are not significant enough to account for the difference in α. Therefore, we postulate that an increase in α arises from the entropic vibrational component of α or changes in scattering of carriers in disordered regions in the film.
我们展示了处理方法如何影响高迁移率半导体聚合物PBTTT薄膜的热电性能。比较了两种掺杂方法：气相沉积（十三氟-1,1,2,2-四氢辛基）三氯硅烷（FTS）或浸入含有4-乙基苯磺酸（EBSA）的溶剂中。热退火后，通过气相沉积FTS掺杂的薄膜在高电子电导率（σ）下产生高塞贝克系数（α），进而产生约100 μW m K的大的功率因数（PF = ασ）。在可比的高σ值下，FTS掺杂的薄膜产生的α值比EBSA掺杂的薄膜高2倍。对X射线散射实验的详细分析表明，来自任何一种掺杂剂的局部结构扰动都不足以解释α的差异。因此，我们推测α的增加源于α的熵振动分量或薄膜无序区域中载流子散射的变化。
