@article{Gao2026, 
author = {Yongsheng Gao and Jiali Chen and Yuanzheng Li and Chuxin Yan and Qingbin Wang and Wei Xin and Weizhen Liu and Haiyang Xu and Yichun Liu},
title = {Twist-angle tunable bandgap renormalization and exciton binding energy in WS2 bilayers},
year = {2026},
journal = {Nano Research},
keywords = {bilayer WS2, twist angle, interlayer coupling, bandgap renormalization, exciton binding energy, dynamic dipole screening},
url = {https://www.sciopen.com/article/10.26599/NR.2026.94909103},
doi = {10.26599/NR.2026.94909103},
abstract = {The twist angle at van der Waals interfaces has emerged as a powerful degree of freedom for tailoring excitonic energy landscapes in two-dimensional semiconductors, yet how interlayer coupling and photoinduced dynamic dipole screening cooperatively govern excitonic responses remains elusive. Here, we directly investigate the twist-angle-dependent Coulomb-dominated excitonic effects in bilayer WS2, including bandgap renormalization (BGR), exciton binding energy, recombination lifetime, and mobility. Femtosecond transient absorption spectroscopy reveals a twist-angle-tunable exciton binding energy from 265 to 336 meV; upon approaching the Mott transition threshold, BGR varies by over 100 meV and is most significant near-30°, where weakened interlayer coupling makes Coulomb interactions dominant. Moreover, the exciton lifetime and mobility are jointly dictated by the twist angle: strong interlayer coupling suppresses recombination while enhancing exciton mobility by threefold. This work integrates photoinduced screening with twist-angle engineering, establishing a unified picture of exciton many-body dynamics and offering guidance for high-performance excitonic devices.}
}