Instant Writing of Conductive Interface on MOF Single Crystal by Ultrafast Laser

Single crystals with excellent properties have been widely used in electronics industries due to their homogeneous and consistent structures. Metal-organic frameworks (MOFs), as a class of crystalline materials that can be synthetically tuned for functionality, are expected to be a favorable candidate for novel electronic devices. However, there is still a lack of methods to efficiently fabricate conductive patterns at the single-crystal scale. Here, laser instant writing of in situ continuous conductive interface on MOF single crystals is reported, enabling the patterning and continuous fabrication of conductive interface at the single-crystal scale. Carbon-wrapped Cu nanoparticles (Cu@C NPs) conductive interface is instantly written using a 1030 nm picosecond ultrafast laser on large HKUST-1 single crystals. It is found that different thermal accumulations can affect the conductivity of Cu@C and transformation of matter phase from Cu NPs to Cu₂O on single crystals is observed as the ablation of carbonaceous materials. As a validation, single-crystal sensor with interdigitated electrodes (IDEs) constructed by laser interface technique shows a wide response range of 5%–90% RH and a fast response time of 2 s toward humidity sensing. This method sheds new light on the construction of functional interface on single MOF crystal, providing a novel strategy for MOF-based electronics.