Effective band gap tuning by Gd doping in bismuth ferrite-lithium vanadate for photovoltaic application

• Published in: Journal of the Indian Chemical Society 2025-01, Vol.102 (1), Article 101523
• Main Authors: Sahu, Meena Kumari, Samantaray, Somya, Naik, Ananga Udaya, Mallick, Priyambada, Biswal, Lalatendu, Mohanty, Debabrata, Satpathy, Santosh Kumar
• Format: Article
• Language: English
• Subjects: Band gap; Doping; Double perovskite; NTCR; Photovoltaic
• ISSN: 0019-4522
• DOI: 10.1016/j.jics.2024.101523

Lead-free double perovskite nanostructures can address stability and toxicity issues in lead halide inorganic perovskite photovoltaic materials. In this work, a novel rare-earth Gd-doped double perovskite material, 0.5(Bi1-xGdxFeO3)–0.5(LiVO3) [x = 0.1,0.2,0.3] was synthesized and investigated its optical and structural characteristics. The traditional solid-state reaction route was employed to fabricate the composite. Using X-ray diffraction for structural characterization, the samples exhibit a change of phase with doping from rhombohedral to tetragonal. The particle size of all samples is 35 nm. SEM study shows a closely packed grain-like structure of 0.5 μm. Energy dispersive X-ray study supported the presence of all material according to nominal stoichiometry. Doping improves the dielectric characteristics. The maximum value of the dielectric constant was nearly 650 and the maximum dielectric loss is nearly 3. Resistive property of the compound has decreased with temperature showing NTCR behavior, much like semiconductor. The activation energy changes with temperature confirming that the Gd-doped sample undergoes a thermally activated conducting process. Doping has been shown to reduce the optical bandgap of bismuth ferrite (BFO), which now has a value of about 1.8 eV. This has improved the photovoltaic responses of the samples. [Display omitted] •This study discusses solid-state preparation of 0.5(Bi1-xGdxFeO3)–0.5(LiVO3).•Lead-free Gd-doped double perovskite enhances stability in photovoltaics.•Doping induces phase transition and reduces BFO optical bandgap to ∼1.8 eV.•Dielectric constant peaks at ∼650, with NTCR behaviour observed in resistivity.•SEM reveals a closely packed grain structure with uniform particle size of 35 nm.