V₂O₉Te₂ Nanorods for Broadband Visible Light Photoresponse and NLO Applications: An Experimental and Computational Approach

In this study, vanadium oxytelluride (VOT) samples were successfully synthesized using a straightforward microwave (MW) method, offering significant advantages by varying the MW power while maintaining a constant irradiation time. The XRD analysis confirmed the V 2 O 9 Te 2 phase of the synthesized samples, which crystallized in an orthorhombic crystal structure having an Fdd 2 space group. Raman analysis exhibited the presence of different vibrational bonds between the constituent elements. The chemical composition and oxidation states of the elements were further elucidated through XPS studies. Microscopic analysis revealed nanorod-like morphologies in all samples, and EDX analysis affirmed the constituent elements. Optical studies indicated bandgap values ranging from 2.6 to 3.45 eV, affirming the semiconducting nature of the VOT samples. The peaks of the photoluminescence (PL) spectra for all the samples were observed between 550 and 750 nm. A red shift in the PL spectra was noted with increasing MW power for synthesis. The samples demonstrated photoresponsivity in illuminated conditions using white LED and UV sources. Key photodetection performance metrics of responsivity and detectivity highlight the potential applicability of VOT materials for photodetector devices. Nonlinear optical (NLO) studies using the Z-scan technique revealed saturable absorption (SA) and a valley–peak mode jibing to the self-focusing effect demonstrate positive n 2 values. The two-photon absorption (2PA) mechanism causes the appearance of NLO properties of the material. Furthermore, χ (3), the third-order NLO susceptibility values, demonstrate the suitability of VOT materials as a potential candidate for many future applications concerning the optoelectronic and NLO fields. The computational studies, combined with the experimental studies, predict some crucial information about diverse properties of the material that are still unexplored.