title: Origins of ultralow thermal conductivity in bulk [6,6]-phenyl-C61-butyric acid methyl ester (PCBM).
abstract: Bulk PCBM has exceptionally low thermal conductivity, 0.07 W m(-1) K(-1) at room temperature. We show that its ultralow thermal conductivity is an intrinsic property. Based on results for thermal conductivity and heat capacity measurements down to <2 K, along with Raman spectroscopy and dilatometry, a new model for minimum thermal conductivity was developed. In the model the thermal energy is transferred between entities of phonons oscillating in a range of frequencies, and limited by the atomic density and the phonon mean speed. The model accurately represents the low thermal conductivity for both PCBM and C60/C70.
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2, Canada. mary.anne.white@dal.ca.
authors.forename: Jan-Hendrik
authors.initials: JH
authors.lastname: Pöhls
authors.affiliation: Institute for Research in Materials, Dalhousie University, Halifax, NS B3H 4R2, Canada and Department of Chemistry, Dalhousie University, Halifax, NS B3H 4R2, Canada.
authors.forename: Michel B
authors.initials: MB
authors.lastname: Johnson
authors.affiliation: Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS B3H 4R2, Canada. mary.anne.white@dal.ca and Institute for Research in Materials, Dalhousie University, Halifax, NS B3H 4R2, Canada.
authors.forename: Mary Anne
authors.initials: MA
authors.lastname: White