A thermally activated and highly miscible dopant for n-type organic thermoelectrics.

Yang, Chi-Yuan; Ding, Yi-Fan; Huang, Dazhen; Wang, Jue; Yao, Ze-Fan; Huang, Chun-Xi; Lu, Yang; Un, Hio-Ieng et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

N-doping plays an irreplaceable role in controlling the electron concentration of organic semiconductors thus to improve performance of organic semiconductor devices. However, compared with many mature p-doping methods, n-doping of organic semiconductor is still of challenges. In particular, dopant stability/processability, counterion-semiconductor immiscibility and doping induced microstructure non-uniformity have restricted the application of n-doping in high-performance devices. Here, we report a computer-assisted screening approach to rationally design of a triaminomethane-type dopant, which exhibit extremely high stability and strong hydride donating property due to its thermally activated doping mechanism. This triaminomethane derivative shows excellent counterion-semiconductor miscibility (counter cations stay with the polymer side chains), high doping efficiency and uniformity. By using triaminomethane, we realize a record n-type conductivity of up to 21 S cm<sup>-1</sup> and power factors as high as 51 μW m<sup>-1</sup> K<sup>-2</sup> even in films with thicknesses over 10 μm, and we demonstrate the first reported all-polymer thermoelectric generator.