Synergistic effects of size and nitrogen doping in modulating the optical and electronic properties of biphenylene quantum dots: a theoretical study

Size modulation and nitrogen doping are considered potential strategies for tuning the optical and electronic properties of biphenylene quantum dots (BPQDs), yet the underlying synergistic mechanisms between these two factors remain unclear. In this work, density functional theory (DFT) and time-dependent DFT (TDDFT) were employed to systematically investigate the combined effects of nine sizes, three nitrogen doping types (edge, surface and pyridinic) and three doping concentrations (2N, 4N, 6N