Nanoscale Decoupling of Carrier–Phonon Transport in Carbon Nanotube–Halide Perovskite Heterostructures

Abstract

In conventional semiconductors, electrical and thermal conductivity are typically coupled, posing a challenge in optimizing both simultaneously. Overcoming this inherent trade-off enables strategies for advancing electronic applications. Herein, a strategy is demonstrated to decouple electrical and thermal conductivity trade-off by creating heterostructures of highly conductive single-walled carbon nanotubes (SWCNTs) coated with low conductivity hybrid perovskites. Coating SWCNTs with methylammonium lead iodide perovskite results in an enhancement in electrical conductivity (408–1266 S cm−1) due to p-type doping followed by a threefold decrease of the in-plane thermal conductivity (3.3–1 W m−1 K−1), compared to pristine SWCNTs. Molecular dynamics simulations uncover phonon boundary scattering at the SWCNT/perovskite interface as well as localization of methylammonium-related and softening of the Pb─I-related phonon modes in methylammonium lead iodide perovskite decreasing the thermal conductivity.