Design Rules for Polymer Blends with High Thermoelectric Performance

A combinatorial study of the effect in-mixing various guests on thermoelectric properties host workhorse polymer poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT) is presented. Specifically, composition and thickness for doped films PBTTT blended with different polymers are varied. Some blends at guest weight fractions around 10–15% exhibit up to a fivefold increase in power factor compared reference material, leading zT values 0.1. Spectroscopic analysis charge-transfer species, structural characterization using grazing-incidence wide-angle X-ray scattering, differential scanning calorimetry, Raman, atomic force microscopy, Monte Carlo simulations employed determine that key improved performance promote long-range electrical connectivity low disorder, together similar highest occupied molecular orbital levels both materials order ensure electronic combined.