Fused Metallo-Carbaporphyrin-Embedded Graphene Nanoribbon Segments

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Graphene nanoribbons (GNRs) and nanoscale polycyclic aromatic hydrocarbons (PAHs) are model systems for graphene and present synthetic challenges.
• Tuning electronic properties of GNRs can be achieved by incorporating porphyrins into their backbone.
• Surface synthesis has been the primary method for creating atomically defined porphyrin-GNR fusions.

Purpose of the Study:

• To develop a solution-phase synthesis for atomically precise porphyrinoid-GNR hybrids.
• To create GNR segments featuring palladium (Pd)II-carbaporphyrin cores with enhanced stability and photothermal properties.
• To investigate the electronic and photophysical characteristics of these novel GNR segments.

Main Methods:

• Utilized hexa-peri-hexabenzocoronene (HBC)-fused carbaporphyrin moieties for GNR segment synthesis.
• Employed solution-phase synthesis techniques to create PdII-carbaporphyrin cores with direct Pd-mediated triply fusion.
• Characterized the synthesized GNR segment using single-crystal X-ray diffraction and analyzed its photophysical properties.

Main Results:

• Successfully synthesized and characterized GNR segments with two PdII-carbaporphyrin cores, exceeding 3 nm in length.
• Observed intense absorption in the NIR-II spectral region and efficient photothermal conversion efficiencies (PCEs) under 980/1064 nm irradiation.
• Demonstrated enhanced photo- and thermal stability due to the rigid Pd-incorporated backbone, overcoming photodegradation issues of organic NIR-II dyes.

Conclusions:

• Developed a novel solution-phase synthetic route for atomically precise porphyrinoid-GNR hybrids featuring metal centers.
• The synthesized GNR segments exhibit promising NIR-II absorption and high PCEs, suitable for photothermal applications.
• The rigid, metal-containing backbone provides significant stability, addressing limitations of current organic NIR-II dyes.