Expanding the Conjugate Structure of Polymeric Carbon Nitride for Enhanced Light Absorption and Photothermal Conversion

The development of efficient and inexpensive materials for light energy conversion is very important for achieving sustainable energy supply and carbon neutrality. Polymeric carbon nitride has become a promising material for light energy conversion due to its advantages of simple preparation and high physical and chemical stability. However, the pristine polymeric carbon nitride only absorbs light with a wavelength of less than 450 nm, and the energy conversion for low‐energy photons is very limited. Here, by introducing the pyromellitic dianhydride component to construct an in‐plane heterostructure, the conjugated structure of polymeric carbon nitride is successfully expanded. This in‐plane carbon nitride‐carbon nanoribbon (C3N4‐C) heterostructure has an ultrawide absorption range from 200 to 2000 nm. Compared with the original material, the photothermal conversion performance of C3N4‐C is significantly improved under the irradiation of Xe lamp or infrared laser. Furthermore, C3N4‐C exhibits good potential for synergistic photothermal and chemotherapy. This work provides a simple strategy to construct expanded conjugate structure for improved light absorption and energy conversion materials based on polymeric carbon nitride. Polymeric carbon nitride and carbon nanoribbon in‐plane heterostructure is fabricated by incorporating pyromellitic dianhydride into carbon nitride, exhibiting broad light absorption, and enhanced photothermal conversion.