Orange-red emitting Gd2Zr2O7:Sm3+: Structure-property correlation, optical properties and defect spectroscopy

Gupta, Santosh K.; Reghukumar, C.; Sudarshan, K.; Ghosh, P. S.; Pathak, Nimai; Kadam, R.M.

doi:10.1016/j.jpcs.2018.01.031

Cited by 37 publications

(11 citation statements)

References 37 publications

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“…The short one is attributed to Eu 3+ ions occupying the distorted HfO 6 octahedra, whereas the long one is attributed to Eu 3+ ions occupying the highly symmetric GdO 8 site. Eu 3+ ions also exhibited biexponential decay in other pyrochlore hosts such as La 2 Hf 2 O 7 , Gd 2 Zr 2 O 7 , and Nd 2 Zr 2 O 7 wherein one of the lifetimes is attributed to A 3+ site occupancy and other to B 4+ site occupancy. ,− Normally, the short lifetime is attributed to asymmetric environment as f–f transition becomes relaxed, and the long lifetime is mostly attributed to symmetric environment as f–f transition is La Porte forbidden. ,− The biexponential behavior can also arise due to other reasons such as the presence of defects, energy transfer, and so forth. This phenomenon has been substantiated with theoretical calculations in the next section.…”

Section: Results and Discussionmentioning

confidence: 99%

Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

et al. 2019

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Crystal structure has a strong influence on the luminescence properties of lanthanide-doped materials. In this work, we have investigated the thermally induced structural transition in Gd 2 Hf 2 O 7 (GHO) using Eu 3+ ions as the spectroscopic probe. It was found that complete phase transition from the disordered fluorite phase (DFP) to the ordered pyrochlore phase (OPP) can be achieved in GHO with the increase of annealing temperature from 650 → 1100 → 1300 °C. OPP is the more stable structural form for the GHOE nanoparticles (NPs) annealed at a higher temperature based on the energy calculation by density functional theory (DFT). The asymmetry ratio of the GHOE-650 NPs was the highest, whereas the quantum yield, luminescence intensity, and lifetime values of the GHOE-1300 NPs were the highest. Emission intensity of Eu 3+ ions increases significantly with the phase transition from the DFP to OPP phase and is attributed to the higher radiative transition rate (281 s –1 ) of the 5 D 0 level of the Eu 3+ ion in the environment with relatively lower symmetry ( C 2 v ) because of the increase of crystal size. As the structure changes from DFP to OPP, radioluminescence showed tunable color change from red to orange. The Eu 3+ local structure obtained from DFT calculation confirmed the absence of inversion symmetry in the DFP structure, which is consistent with the experimental emission spectra and Stark components. We also elucidated the host to dopant optical energy transfer through density of states calculations. Overall, our current studies present important observations for the GHOE NPs: (i) thermally induced order–disorder phase transition, (ii) change of point group symmetry around Eu 3+ ions in the two phases, (iii) high thermal stability, and (iv) tunability of radioluminescent color. This work provides fundamental understanding of the relationship between the crystal structure and photophysical properties of lanthanide-doped materials and helps design a strategy for advanced optoelectronic materials.

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Section: Results and Discussionmentioning

confidence: 99%

Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

et al. 2019

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“…Recent attempts to achieve highly efficient red emission have focused on the doping of materials with rare earth ions. Sm 3+ can achieve highly efficient red‐orange light emission, and high absorbance around 404 nm, which means that it can be effectively excited by an InGaN diode laser, and there are several reports of the optical properties of Sm 3+ in various matrixes, including zirconia phosphors, nanotube arrays, and films . However, to the best of our knowledge, there have been no previous reports of the properties of Sm 3+ doped into yttrium‐stabilized zirconia (YSZ) single crystals.…”

Section: Introductionmentioning

confidence: 99%

Preparation and optical properties of samaria‐doped yttria‐stabilized zirconia single crystals

Tan

Wang

et al. 2019

J Am Ceram Soc

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Single crystals of yttria‐stabilized zirconia (YSZ) doped with various concentrations of Sm2O3 were synthesized by the optical floating zone method, and their structure and spectroscopic properties characterized using powder X‐ray diffraction (XRD), optical absorption, and luminescence measurements. XRD showed that the cubic phase of ZrO2 was stabilized by addition of Y2O3 and a series of absorption peaks characteristic of Sm3+ was detected by UV‐visible absorption spectroscopy. Three phenomenological J‐O oscillator strength parameters Ωt (t = 2, 4, 6) were calculated to evaluate the local structure and bonding in the vicinity of the Sm3+ for the 0.75 mol% Sm2O3: YSZ sample. These were in order of Ω2 < Ω4 < Ω6 with values of Ω2 = 5.46 × 10−20 cm2, Ω4 = 10.70 × 10−20 cm2, and Ω6 = 12.67 × 10−20 cm2, and indicate a relatively high symmetry and low covalent character for the Sm‐O bond at the Sm3+ sites in the YSZ matrix. Photoluminescence spectra recorded under an excitation of 404 nm showed four emission bands centered at 571 nm, 621 nm, 652 nm, and 716 nm corresponding to the transitions 4G5/2→6Hj (j = 5/2, 7/2, 9/2, 11/2). The transition probability, lifetime, and branching ratio obtained from the emission spectrum of the 0.75 mol% Sm2O3: YSZ crystal showed that YSZ is a potential host for Sm3+ to achieve a reddish‐orange laser output, and the Sm3+‐modified YSZ crystals have a possible use in reddish‐orange laser and lighting devices.

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“…The first positron lifetime is in close agreement with the positron lifetimes reported on other pyrochlores of the A 2 B 2 O 7 type synthesized at similar temperatures. 40,50,51 In most oxides, the first lifetime component is a combination of positron annihilation in the bulk with few positron traps close by. The dopant Sm 3+ ion is isovalent to La 3+ but smaller in size, while it differs both in size and valency with Ce 4+ .…”

Section: Resultsmentioning

confidence: 99%

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration

et al. 2022

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Orange-red emitting Gd2Zr2O7:Sm3+: Structure-property correlation, optical properties and defect spectroscopy

Cited by 37 publications

References 37 publications

Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

Preparation and optical properties of samaria‐doped yttria‐stabilized zirconia single crystals

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration

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Orange-red emitting Gd2Zr2O7:Sm3+: Structure-property correlation, optical properties and defect spectroscopy

Cited by 37 publications

References 37 publications

Thermally Induced Disorder–Order Phase Transition of Gd2Hf2O7:Eu3+ Nanoparticles and Its Implication on Photo- and Radioluminescence

Thermally Induced Disorder–Order Phase Transition of Gd2Hf2O7:Eu3+ Nanoparticles and Its Implication on Photo- and Radioluminescence

Preparation and optical properties of samaria‐doped yttria‐stabilized zirconia single crystals

Modulating the optical and electrical properties of oxygen vacancy-enriched La2Ce2O7:Sm3+ pyrochlore: role of dopant local structure and concentration

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Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

Thermally Induced Disorder–Order Phase Transition of Gd₂Hf₂O₇:Eu³⁺ Nanoparticles and Its Implication on Photo- and Radioluminescence

Modulating the optical and electrical properties of oxygen vacancy-enriched La₂Ce₂O₇:Sm³⁺ pyrochlore: role of dopant local structure and concentration