UV-guided enhanced green luminescence in Y2O3/ZnO:Tb3+ composite via induced defect state and applied for latent fingerprinting application

The Y₂O₃/ZnO:Tb³⁺ composite was synthesized through the solid-state reaction method. XRD analysis confirms the phase formation corresponding to JCPDS #36–1451 (ZnO) and #43–1036 (α-Y₂O₃), revealing nano order crystallinity, negative strain, and 76:24 % occupancy of Y₂O₃/ZnO. The submicron-sized particles subsequently increased upon Tb³⁺ doping as shown in FE-SEM images. Elemental mapping and XPS analyses confirm the composition, oxidation state, and presence of oxygen vacancies. The DRS spectra show that the band gaps of Y₂O₃ & ZnO are 5.28 eV and 3.27 eV, respectively. An intense green emission at 520 nm due to ZnO defect states and at 543 nm due to ⁵D₄→⁷F₅ transition was observed under λ_Ex = 378 and 305 nm, respectively. Interestingly, ZnO emits a broad band from 385 to 700 nm region through 378 or 340 nm excitations. The Tb³⁺ ion-induced tunability due to modification in defects, is well supported by decay analysis. The intense green and whitish green emission of Tb³⁺ ion and composite has been successfully applied in latent fingerprint detection.