Ultraviolet emission from 2D tellurium nanosheets synthesised using diverse exfoliation techniques

We report the reproducible synthesis of ultraviolet (UV) photoluminescence (PL) emission from tellurium nanosheets (TeNS) through three distinct top-down exfoliation methods, probe sonication, cryo-assisted synthesis and shear-induced fracturing. Despite differing synthesis processes, all approaches yield few-layer thick (0.6–6.4 nm) TeNS with consistent structural integrity and prominent UV emission centred at 340 nm (3.65 eV). Systematic optical characterisation reveals transitions from p-bonding triplets to p-antibonding triplets, manifested as two characteristic absorption peaks around ~ 230–240 nm (5.16–5.39 eV) and ~ 270–280 nm (4.43–4.60 eV). XRD and Raman studies confirm the crystalline features of TeNS, while FTIR spectra indicate surface/ edge hydroxylation, which enhances their dispersion stability in an aqueous medium. The method-independent reproducibility of UV emission can be attributed to the surface states influenced by hydroxyl functionalisation rather than arising from the intrinsic bandgap of TeNS. These findings suggest solution-processed TeNS as UV emitters with potential for optoelectronic applications.