Ice sublimation transfer of vertically aligned carbon nanotubes for residue-free and structure-preserving integration

Vertically aligned carbon nanotubes exhibit exceptional properties but typically require high temperature (> 700 °C) for growth, thereby complicating low-temperature device integration. Herein, an ice sublimation-based transfer process is proposed for integrating vertically aligned carbon nanotubes into diverse substrates without structural damage. Ambient vapor is condensed under controlled atmospheric conditions to form a thin and uniform ice layer on the acceptor substrate, serving as a temporary adhesive. After transfer, the ice sublimes, enabling the clean release of vertically aligned carbon nanotubes with no residual contaminants while preserving their pristine vertical architecture. Vertically aligned carbon nanotube micropatterns with feature sizes ranging from 10 µm to 1 cm are successfully transferred, achieving yields exceeding 95%. To broaden its practical applications in electronics, micropatterned vertically aligned carbon nanotubes have been successfully transferred onto various substrates like silicon wafers, polymers, and metals, while retaining their electrical, optical, and thermal properties. Furthermore, the transferred vertically aligned carbon nanotubes function as thermal interface materials that reduced smartphone hotspot temperature by 4 °C compared to commercial thermal interface materials, and as infrared absorbers that enhanced sensor sensitivity by up to 3.43-fold. This sublimation-based transfer method expands the potential for direct vertically aligned carbon nanotube integration in next-generation electronic systems.