Quasiparticle Effects and Strong Excitonic Features in Exfoliable 1D Semiconducting Materials

High Resolution Image Download MS PowerPoint Slide We report a first-principles study of the electronic and optical properties of recently identified one-dimensional semiconducting materials exfoliable from van der Waals-bonded bulk crystals. Specifically, we investigate four chalcogenide-based atomic chains, the covalently bonded S 3 and Te 3 chains, and polar-bonded As 2 S 3 and Bi 2 Te 3 chains, using a fully first-principles approach that combines density functional theory (DFT), density functional perturbation theory (DFPT), and many-body perturbation theory within the GW approximation and Bethe–Salpeter equation (BSE). Our vibrational analysis shows that the isolated, freestanding wires remain dynamically stable, with the zone-center optical phonon modes leading to infrared activity. The main finding of this study is the presence of very strong exciton binding energies (1–3 eV), which make these exfoliable 1D materials suitable platforms for room-temperature excitonic applications. Interestingly, the exciton character remains Wannier–Mott-like, as indicated by average electron–hole separations greater than the lattice constant. Notably, the optical gaps of these materials span a wide range ─ from infrared (0.8 eV, Bi 2 Te 3 ), through the visible spectrum (yellow: 2.17 eV, Te 3; blue: 2.71 eV, As 2 S 3 ), up to ultraviolet (4.07 eV, S 3 ) ─ highlighting their versatility for broadband optoelectronic applications. Our results offer a detailed, many-body perspective on the optoelectronic behavior of these low-dimensional materials and underscore their potential for applications in nanoscale optoelectronic devices.