To enhance the photothermal performance of TMC, we developed a plasma-assisted ALE process to modify its surface chemistry, converting the surface terminations from fluorine-dominated to oxygen-dominated (see Figure ). We investigated the optimal O 2 :Ar ratio in the plasma-ALE treatment. As shown in Figure , all plasma treatment cases increased the conductivity of TMC films, demonstrating that plasma ALE can effectively remove conductivity-reducing terminations (e.g., -F). These results underscore the importance of balanced gas composition in achieving optimal surface modification. The highest conductivity increase (80% compared to the original TMC film) was achieved by 50:50 Ar:O 2 ratio. This optimal ratio maximized the advantages of both O 2 and Ar plasma etching, with Ar and O 2 plasma synergistic effects, creating an oxygen-dominated surface with improved out-of-plane charge transport by enhancing the density of states and shifting the Fermi level, resulting in better interlayer electron mobility and, thus, overall conductivity in the films of stacked multi-layer MXene. The effect of treatment duration was also examined, as shown in Figure . The 5-minute treatment resulted in the highest conductivity, followed by the 1-minute treatment, while the 10-minute treatment yielded the lowest conductivity. The improved conductivity after short plasma treatment is attributed to modifications confined to the surface terminations, converting them to oxygen-dominated ones. With increased treatment duration, anatase TiO 2 began forming at the borders of TMC through oxidation, introducing orbital symmetry breaking of p-d hybridized orbitals and facilitating out-of-plane charge transfer pathways via the derived Ti-O bonds, thereby further enhancing the interfacial conductivity in TMC. However, excessively prolonged treatment led to over-etching and structural distortion of the TMC, which subsequently decreases in conductivity. It was also worth noting that the 5-minute treatment caused significant edge curling of the PC membrane substrate, which compromised the actuator's mechanical performance. In contrast, the 1minute treatment preserved membrane integrity while only slightly reducing conductivity. Treatments exceeding 10 minutes severely damaged the PC membrane. Therefore, the 1-minute treatment appears to be optimal, balancing conductivity enhancement with the preservation of substrate mechanical properties.