Reduction of the Lattice Thermal Conductivity of Polymer Semiconductors by Molecular Doping
Osnat Zapata‐Arteaga, Aleksandr Perevedentsev, Sara Marina, Jaime Martín, J. S. Reparaz, Mariano Campoy‐Quiles
Abstract
]thiophene) (PBTTT) doped with molecular acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). The thermal conductivity of neat PBTTT films is dominated by the degree of crystallinity, with thermal percolation observed for annealing temperatures >170 °C. Upon doping the samples with a relatively low amount of F4TCNQ (anion content <1 mol %), the thermal conductivity exhibits a two-fold reduction without compromising the crystalline quality, which resembles the effect of alloy scattering observed in several inorganic systems. The analysis of the relation between thermal and electrical conductivities shows that thermal transport is dominated by a doping-induced reduced lattice contribution.