Dopant-driven modulation of electronic properties in hydrogen-terminated biphenylene nanoribbons: enhancing optoelectronic potential with doping and mechanical strain

Abstract The biphenylene network (BPN), a recently discovered two-dimensional carbon polymorph, naturally exhibits metallic properties, posing a challenge for its integration into semiconductor technologies. To overcome this limitation, precise band gap modulation is essential, which can be achieved through carefully crafted strategies. In this context, the hydrogen-terminated one-dimensional counterpart of BPN, doped with B, N, or B–N pairs with different concentrations are systematically studied here, to explore its band gap modulation and electronic property enhancement. The effect of mechanical strain on further tunning the band gap is also investigated, using the first-principles calculations. The findings reveal that dopants effectively modulate the band gap, spanning approximately 0.2–1.6 eV, while also altering the band gap nature. Mechanical strain introduces further tunability, enabling adjustments of around ±0.5 eV. Among the do pants, B-doped systems display the most significant band gap variations, surpassing those observed in N and B–N co-doped systems. Additionally, doping substantially impacts the electron and hole effective masses, yielding low charge carrier effective masses (approximately 0.02 m 0 –0.09 m 0 ), indicative of high charge carrier mobility and ambipolar behavior. Also, doping shifts absorption peaks to lower energies (B: 1.05–1.25 eV, N: < 0.8 eV), while B–N co-doping enhances intensity and broadens the spectrum, with strain having minimal effect on optical properties. This study highlights the remarkable tunability of doped BPN nanoribbons, presenting them as promising low-dimensional candidates, a possible alternative for graphene nanostructures for the application in transistors, light-emitting diodes, and solar cells.