Fig. 5

Calculated thermal boundary resistance of the various samples. In order to simulate the practical work condition of electronic devices, the performances of the resulting TIMs under high temperature are detected (a). With increased temperature, the thermal conductivities of all TIMs decrease due to the enhanced Umklapp scattering. Although the Kapitza boundary scattering decreases at the same time (the probability of a phonon across the interface is proportional to \( \sim {e}^{\frac{-E}{KT}} \)), the decrease cannot remedy the corresponding increase of the Umklapp scattering, leading to the whole decrease of thermal conductivity. Compared with that of the 3DGN-assisted sample, the stability of thermal conductivity of the RGO nanosheets added composites under high temperature is better because of the more sensitive Kapitza boundary scattering (as a results of the more boundaries of the RGO nanosheets). Moreover, no obvious degradation can be found for the thermal performance of the RGO-3DGNs-ER sample after 240 h continuous working (b), indicating the potential promising prospect of this TIM. The stability of the pure ER during a long work time is also recorded in b. The similar stabilities of the pure ER and the resulting composites (all the degradations of their thermal conductivities are less than 10%) indicate that no significant influence on the thermal stability can be found after adding the fillers