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Structural, Vibrational, Optical and Improved Photoluminescence Properties of ­Dy3+ Doped C ­ a2KZn2V3O12 Phosphors T. Jeyakumaran1 · N. Venkatesh Bharathi1 · R. Shanmugavel2 · P. Sriramachandran2 · S. Ramaswamy1  Received: 29 June 2020 / Accepted: 21 September 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract A series of dysprosium (­ Dy3+) ion doped C ­ a2KZn2V3O12 phosphors were explored which exhibits a broad band and sharp peaks in the visible region under the ultraviolet light excitation. Fourier transform infrared (FTIR) spectra and the optical diffuse reflectance spectra were ascribing the formation of the distorted V ­ O4 tetrahedral group due to the influence of D ­ y3+ 3+ ions. Moreover, a tunable luminescence color was achieved by doping of ­Dy ion in the ­Ca2KZn2V3O12 phosphor. Through doping concentration optimization, the C ­ a2KZn1.9Dy0.1V3O12 phosphor was observed for high color rendering index (CRI) and excellent correlated color temperature (CCT) with cool white emission. Hence, in the designing of the V ­ O4 → Dy3+ energy transfer that is capable of converting ultraviolet light into efficient white light, this phosphor is suitable for solid-state lighting applications. Keywords  Vanadate garnet · Luminescence · Solid state reaction · f–f transition · W-LEDs

1 Introduction So far, extensive research has been focused on garnet vanadate phosphors due to the higher material stability, excellent optical absorption in the ultraviolet (UV) region, and high composition flexibility. Moreover, the luminescence properties of the material can be controlled by the incorporation of suitable dopants in their host lattice [1]. In the past decade, it has been reported that the pure and rare-earth activated garnet vanadate materials can be used in the various fields of applications such as optical temperature sensing, safety signal in high-temperature environment, non-contact optical thermometer, display devices, photonic display, microwave dielectric, field-emission displays, spectral converter and photocatalytic activity [2–15]. Further, the color-tunable luminescence properties have been achieved by many rareearth activated garnet vanadate phosphors and some of the phosphors have been practically demonstrated as UV-chip converted solid-state lighting devices [16–24]. * S. Ramaswamy [email protected] 1



PG and Research Department of Physics, N.M.S.S.V.N. College, Madurai, Tamilnadu 625 019, India



Physics Research Centre, V.H.N.S.N. College, Virudhunagar, Tamilnadu 626 001, India

2

Recently, a self-activated C ­ a2KZn2V3O12 phosphor has been reported as an excellent luminescent material for UV-chip converted solid-state white light emitting devices [25, 26]. This phosphor shows a broad absorption in the UV (200–400 nm) region and broad emission spectra in the visible (400–750 nm) region. Besides, the optical bandgap energy and vibrational properties of C ­ a2KZn2V3O12 phosphor have also been investigated [26]. Similarly, a series of white light-emitting E ­ u3+ io