X-ray absorption spectroscopy investigations on electronic structure and luminescence properties of Eu:SnO2-SnO nanocomposites

• Eu: SnO2-SnO nanocomposites were synthesized using co-precipitation method.
• XRD, XANES and photoluminescence measurements were performed.
• Eu3+ ions were dominantly present in Eu doped samples.
• Sn M-edge and Sn K-edge XANES confirmed the Sn4+ and Sn2+ valence of tin in nanocomposites.
• High emission characteristics are achieved by Eu insertion in the weakly emitting SnO2-SnO nanocomposites.

Tin oxide nanostructures are nontoxic in nature and biocompatible. However, they exhibit weak emission characteristics that limit their applications in cellular and biology fields. Therefore, it is important to enhance luminescence properties in this oxide and establish a relationship between the local electronic structure and emission characteristics. In this report, we demonstrate significant advancement in the photoluminescence (PL) properties in the Eu incorporated SnO2-SnO nanocomposites. Eu:SnO2-SnO nanocomposites were synthesized by chemical precipitation method. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and PL measurements were performed to investigate the structural, electronic structure and emission properties of the samples. Eu3+ ions, as confirmed by the Eu M5,4-edge XANES studies, lead to defect formation and local electronic structural perturbation in the nanocomposites. The O K-edge and Sn M5,4-edge XANES studies confirm a net decrease in the hybridization of O 2p and Sn 5s/5p states and formation of Sn defects, upon Eu doping. Significant enhancement in the Eu3+ related interband transitions (5D0-7FJ; J = 0,1,2,3,4) is achieved upon increasing the Eu concentrations, indicating synthesis of emission characteristic rich SnO2-SnO nanocomposites.

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