ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Comparative study of photoluminescence properties of samarium vanadate and Dy-doped samarium vanadate

Bhavani Chakravarti, Anand Prakash Mishra, and Rajan Kumar Singh

Department of Chemistry, Dr. Harisingh Gour University, Sagar, India

E-mail: bhavaniprajapati87@gmail.com

Received: 30 September 2022  Accepted: 3 January 2023

Abstract:

In this research work, the luminescence characteristics of SmVO₄ and Dy³⁺-doped SmVO₄ have been compared. The hydrothermal approach was used to synthesize these new phosphors. Characterization of the synthesized products has been done by employing powder X-ray diffraction (P-XRD), Fourier transform infrared (FTIR), transmission electron microscopy and scanning electron microscopy (TEM and SEM/EDX), photoluminescence techniques, Raman spectroscopy as well as UV–visible diffuse reflectance spectroscopy (UV-DRS). The formation of the tetragonal crystalline phase is demonstrated by the powder X-ray diffraction graph. Morphological findings reveal that the samples contain regular bipyramidal structures. According to functional group analysis, Sm–O absorption is associated with the band at 529 cm⁻¹. The symmetrical stretching caused by the V–O vibration of the VO₄³⁻ group corresponds to a strong band near 775 cm⁻¹. Detailed information about the phase composition is studied by Raman spectroscopy. It can be observed from Raman spectra that the V–O bond’s symmetric stretching mode can be seen at 873 cm⁻¹, whereas asymmetric stretching modes can be seen at 795 cm⁻¹ and 811 cm⁻¹. Furthermore, from the photoluminescence emission spectra, it can be suggested that the emission intensity of samples varied significantly as the amount of Dy³⁺ ion dopants was varied, although the locations of emission bands remained nearly identical. This was due to the well-known phenomenon, i.e. energy transfer (ET) between dysprosium ion and samarium ion. The most intense emission peaks were noticed at 550 nm (caused by ⁴F_9/2 → ⁶H_13/2 transition of Dy³⁺ and ⁴G_5/2 → ⁶H_5/2 transition of Sm³⁺) and at 663 nm (due to ⁴F_9/2 → ⁶H_11/2) on excitation at 405 nm. The optimal concentration of Dy³⁺ ion doping for improving the photoluminescence properties of samarium vanadate phosphor was determined to be 5 at%. The energy band gaps of SmVO₄ and SmVO₄:x at% Dy³⁺ (x = 1, 3, 5, 7, 10, and 15) were calculated using the Tauc relation and found to be between 3.73 and 3.81 eV. Their estimated CIE chromaticity colour coordinates (x, y) for SmVO₄:5 at% Dy³⁺ are (0.43, 0.54). It could be used in a variety of optical devices.

Keywords: Samarium vanadate; Orthovanadate; Zircon-type structure; Photoluminescence; Monazite-type structure

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-02669-8

Chemical Papers 77 (5) 2827–2838 (2023)