  We have measured the thermal resistances of thin films of the small molecule
organic semiconductors bis(triisopropylsilylethynyl) pentacene (TIPS-pn),
bis(triethylsilylethynyl) anthradithiophene (TES-ADT) and difluoro
bis(triethylsilylethynyl) anthradithiophene (diF-TES-ADT). For each material,
several films of different thicknesses have been measured to separate the
effects of intrinsic thermal conductivity from interface thermal resistance.
For non-crystalline films of all three materials, with thicknesses ranging from
< 100 nm to > 4 microns, the thermal conductivities are similar to that of
polymers and over an order of magnitude smaller than that of the crystals,
reflecting the large reduction in phonon mean-free path in the films. Thin (<
205 nm) crystalline films of TES-ADT, prepared by vapor-annealing spin-cast
films, have also been measured, but for these the thermal resistances are
dominated by interface scattering.
