Near-Infrared Photothermal Metal-Organic Framework for Ultralow-Power-Density Laser Ablation and Direct Patterning

Direct laser writing (DLW) based on laser ablation offers a powerful approach for the precise fabrication of micro- and nanoarchitectures from functional materials. The advancement of this method heavily depends on the development of laser-responsive materials that allow for efficient ablation under mild conditions. Although metal-organic frameworks (MOFs) have shown promise for such applications, most systems require extremely high laser power densities, typically exceeding 10⁴ W/cm², to achieve effective ablation, which significantly increases energy consumption and poses challenges to the scalability of practical applications. Herein, we report a NIR photothermal MOF, {[La₂(HL)₂(L)₂(H₂O)₆]·xDMF}_n (1). Compound 1 exhibits broad optical absorption from the ultraviolet to the near-infrared (NIR) region. Under irradiation with an 808 nm laser, compound 1 demonstrates a pronounced NIR photothermal conversion efficiency (PCE) of 86.47%, attributed to the synergistic effects of the charge transfer states and abundant π-π interactions within the framework. Notably, laser ablation of 1 occurs at a power density as low as 9.87 W/cm², significantly lower than the previously reported thresholds for MOFs. At this threshold, compound 1 is converted to amorphous lanthanum oxide and graphene oxide (GO) in air. Furthermore, direct laser writing is successfully demonstrated, enabling precise patterning of both English and Chinese characters on pressed pellets.