In this study, we explore the structural and electronic properties of heterojunctions composed of biphenylene nanoribbons (BPN) and biphenylene-boron nitride (BPN-BN) through first-principles simulations. Biphenylene is a recently synthesized twodimensional form of carbon, characterized by its square lattice of benzene rings. The introduction of boron nitride (BN) into BPN nanoribbons creates heterojunctions with unique properties due to the contrast between the metallic nature of BPN and the insulating properties of BN.

We employed density functional theory (DFT) calculations to investigate the stability of the BPN/BPN-BN heterojunctions, analyzing parameters such as binding energy, electronic structure, density of states, and excitonic properties. The results indicate that the interface between BPN and BPN-BN maintains good structural stability, enabling the formation of viable heterojunctions for electronic device applications.

The investigation of the electronic transport properties of the BPN-BN heterojunctions was conducted using first-principles calculations. The data indicated a significantly variable carrier mobility in the heterojunctions compared to pure BPN nanoribbons. Another important aspect is the presence of excitons, which can significantly modify the optical properties of the nanoribbons. Excitons, quasi-particles formed by the binding of an electron with a hole through Coulombic forces, play a crucial role in determining the optical properties of the nanoribbons. Manipulating excitons in BPN and BPN-BN heterojunctions could lead to significant advancements in light-emitting technologies, photodetectors, and solar cells. This study highlights the capability of excitons to influence electronic interactions in heterojunctions, providing valuable insights for the development of efficient optoelectronic devices.

In conclusion, this study demonstrates that BPN-BN heterojunctions possess superior structural, electronic, and optical properties, making them promising for a wide range of technological applications. The detailed characterization of the heterojunctions opens new possibilities for nanoscale material engineering, offering valuable insights for future research and the development of advanced devices.