Understanding and Controlling Photothermal Responses in MXenes

Abstract

MXenes have the potential for efficient light-to-heat conversion in photothermal applications. To effectively utilize MXenes in such applications, it is important to understand the underlying nonequilibrium processes, including electron−phonon and phonon− phonon couplings. Here, we use transient electron and X-ray diffraction to investigate the heating and cooling of photoexcited MXenes at femtosecond to nanosecond time scales. Our results show extremely strong electron−phonon coupling in Ti 3 C 2 -based MXenes, resulting in lattice heating within a few hundred femtoseconds. We also systematically study heat dissipation in MXenes with varying film thicknesses, chemical surface terminations, flake sizes, and annealing conditions. We find that the thermal boundary conductance (TBC) governs the thermal relaxation in films thinner than the optical penetration depth. We achieve a 2-fold enhancement of the TBC, reaching 20 MW m −2 K −1 , by controlling the flake size or chemical surface termination, which is promising for engineering heat dissipation in photothermal and thermoelectric applications of the MXenes.

Carbonized Syndiotactic Polystyrene/Carbon Nanotube/MXene Hybrid Aerogels with Egg-Box Structure: A Platform for Electromagnetic Interference Shielding and Solar Thermal Energy Management

“…Composite PCMs based on CCM-x-y aerogels demonstrated a significantly efficient solar thermal energy conversion capacity due to the presence of carbon materials 78 and MXene. 46 The samples' surface temperature was measured using a homemade experimental setup, as depicted in Figure 7a. Two samples, including CCM-4-6 and PCM-4-6, were exposed to simulated solar light, and their surface temperature changes were monitored using an infrared imager.…”

“…Composite PCMs based on CCM- x - y aerogels demonstrated a significantly efficient solar thermal energy conversion capacity due to the presence of carbon materials and MXene . The samples’ surface temperature was measured using a homemade experimental setup, as depicted in Figure a.…”

“…Meanwhile, MXene possesses other appealing properties, including advanced thermal, optical, and hydrophilic surface functionalities. ,, Therefore, beyond EMI shielding, MXene-based composites were designed with multifunctionalities. For instance, high-efficiency EMI shielding and heat dissipation synergy materials were achieved by the lamellar MXene/aramid nanofiber (ANF) composite films with a nacre-like structure .…”

Role of MXenes in advancing soft robotics

“…These include actuation, sensing, and manipulation, wherein the formation of localized heat can induce shape changes, trigger responses, or enable controlled movements in the soft robotic systems. 53–56…”

“…These include actuation, sensing, and manipulation, wherein the formation of localized heat can induce shape changes, trigger responses, or enable controlled movements in the soft robotic systems. [53][54][55][56] Many studies have focused on designing stretchable energystorage devices for untethered soft robotics, wearable electronics, and implantable medical devices. Li et al 33 introduced a zinc (Zn)-based battery with high stretchability due to the presence of MXene (V 2 CT x ) cathodes and Zn-decorated MXene (Ti 3 C 2 T x ) anodes, showing crumple-like micro-textures allowing reversible folding/unfolding performances for attenuating the in-plane stress while stretching.…”