Thermal conductivity of one-dimensional organic nanowires: effect of mass difference phonon scattering

We report the thermal conductivity of π-stacked metallophthalocyanine nanowires using the thermal bridge method. In the temperature range of 20-300 K, the thermal conductivity of copper phthalocyanine nanowires (CuPc NWs) and iron phthalocyanine nanowires (FePc NWs) increases with temperature and reaches a peak value at around T = 40 K, then decreases at a higher temperature following T ^-1 behavior. For three FePc NWs, the peak values are 7.1 ± 1.21, 8.3 ± 1.33, and 7.6 ± 1.42 Wm^-1 K^-1, respectively. The peak thermal conductivity is 6.6 ± 0.67 and 6.6 ± 0.51 Wm^-1 K^-1 for the two CuPc nanowires. The thermal conductivity of FePc NWs is slightly larger than that of CuPc NWs, which is believed to result from the different mass of metal atoms in the phthalocyanine centers, indicating a phonon mass-difference scattering effect. Meanwhile, the thermal contact conductance of the FePc-Pt interface is measured, which will benefit from a better understanding of the thermal transport across dissimilar interfaces.