Trigonal Lattice Research Articles

A study using physical sphere-in-contact models to investigate the structure of close-packed nanoparticles supported on flat hexagonal, square and trigonal lattices

The tailored design of nanoparticles becomes more important with the advancement of heterogeneous catalysis and materials science. The formation of nanoparticles in catalysts with a specific geometry of the active site becomes necessary to improve activity and selectivity in catalysis. Here we have used physical sphere-in-contact models of various nanoparticles with hexagonal, square and trigonal geometries on flat close-packed surfaces to understand how the distribution of (100) and (111) sites changes as a function of nanoparticle (NP) size in a simplified model of nanoparticle supported metals. The results from this approach clearly show that in 2-layer NPs that have a hexagonal base have 2–3 times more (100) sites than the square and trigonal base NPs as a function of the number of atoms in the NP. In 3D isotropic NPs, this phenomenon is even more pronounced than the 2-layer NPs. We derive equations that estimate the number of (100), (111), the number of atoms and the aspect ratio as a function of n. These equations are important in tailoring the properties of NPs supported on close-packed metal surfaces, which may find applications in materials science, nanotechnology and catalysis.

3D electron diffraction studies of synthetic rhabdophane (DyPO4·nH2O).

In this study, we report the results of continuous rotation electron diffraction studies of single DyPO4·nH2O (rhabdophane) nanocrystals. The diffraction patterns can be fit to a trigonal lattice (P3121) with lattice parameters a= 7.019 (5) and c= 6.417 (5) Å. However, there is also a set of diffuse background scattering features present that are associated with a disordered superstructure that is double these lattice parameters and fits with an arrangement of water molecules present in the structure pore. Pair distribution function (PDF) maps based on the diffuse background allowed the extent of the water correlation to be estimated, with 2-3 nm correlation along the c axis and ∼5 nm along the a/b axis.

Tailoring magnon modes by extending square, kagome, and trigonal spin ice lattices vertically via interlayer coupling of trilayer nanomagnets

In this work high-frequency magnetization dynamics and statics of artificial spin-ice lattices with different geometric nanostructure array configurations are studied where the individual nanostructures are composed of ferromagnetic/non-magnetic/ferromagnetic trilayers with different non-magnetic thicknesses. These thickness variations enable additional control over the magnetic interactions within the spin-ice lattice that directly impacts the resulting magnetization dynamics and the associated magnonic modes. Specifically the geometric arrangements studied are square, kagome and trigonal spin ice configurations, where the individual lithographically patterned nanomagnets (NMs) are trilayers, made up of two magnetic layers of Ni81Fe19 of 30 nm and 70 nm thickness respectively, separated by a non-magnetic copper layer of either 2 nm or 40 nm. We show that coupling via the magnetostatic interactions between the ferromagnetic layers of the NMs within square, kagome and trigonal spin-ice lattices offers fine-control over magnetization states and magnetic resonant modes. In particular, the kagome and trigonal lattices allow tuning of an additional mode and the spacing between multiple resonance modes, increasing functionality beyond square lattices. These results demonstrate the ability to move beyond quasi-2D single magnetic layer nanomagnetics via control of the vertical interlayer interactions in spin ice arrays. This additional control enables multi-mode magnonic programmability of the resonance spectra, which has potential for magnetic metamaterials for microwave or information processing applications.

Revealing Dynamic Evolution of the Anode‐Electrolyte Interphase in All‐Solid‐State Batteries with Excellent Cyclability

AbstractAll‐solid‐state‐batteries (ASSBs) based on a halide solid electrolyte (SE) and a lithium‐metal based anode typically have poor cyclability without a buffer layer (such as Li3PS4 or Li6PS5Cl) to prevent the degradation reactions. Here excellent cycling stability of ASSB consisting of an uncoated single‐crystal LiNi0.8Co0.1Mn0.1O2 cathode and a Li3YCl6 (LYC) SE separator in direct contact with a Li‐In anode are demonstrated. Through a combination of electrochemical measurements, synchrotron micro‐X‐ray absorption and diffraction analyses, and density functional theory calculations, reveal for the first time that along with the standard Li+ transport during charge/discharge, indium in the Li‐In anode also participates in the redox reactions. The in‐situ generated In3+ preferentially occupies the vacant Li sites in the trigonal LYC lattice, leading to the formation, growth, and eventual stabilization of an anode‐electrolyte interphase (AEI) layer consisting of an In‐doped Li3‐xInxYCl6 (x = ≈0.2) phase. It is discussed how the presence of such an AEI layer prevents LYC decomposition and suppresses dendrite formation and propagation, enabling stable cycling of ASSB with ≈90% capacity retention over 1000 cycles. This work sheds light on the dynamic evolution of the halide SE and alloy anode interphase, and opens new avenues in the future design of long‐lasting high‐energy all‐solid‐state‐batteries.

Low-Cost, Multifunctional, and Sustainable Sodium Sulfido Ferrate(II).

We introduce Na2[Fe3S4], comprising anionic layers, synthesized by a simple and straightforward solid-state method based on the fusion of binary sulfides of abundant sodium and iron. The structure crystallizes in a trigonal lattice with honeycomb cavities, as well as 25% of statistical iron vacancies in the crystal structure. The compound depicts high dielectric constants from 998 to 1850 at a frequency of 1 kHz depending on the sintering temperature, comparable with benchmark dielectric materials. According to the complex electrochemical impedance results, the compound depicts an electrical conductivity at ambient temperature. Optical investigations reveal a band gap of 1.64 eV, which is in agreement with an electronic band gap of 1.63 eV computed by density functional theory calculations. Magnetometry results reveal an antiferromagnetic behavior with a transition at 120 K. These findings introduce Na2[Fe3S4] as a sustainable multifunctional material with potential for a variety of electronic and magnetic applications.

Investigation of Zirconium Disulphide Quantum Dots for Supercapacitor Applications

AbstractThe Transition metal dichalcogenides (TMDs) attract more interest because of their layered structure and high surface‐volume ratio. Most works are based on 3D and 2D, there is scarce research on its reduced dimensionality. In this study, Zirconium disulfide (ZrS2) (where M = Zr, X = S) Quantum Dots (QDs) are synthesized by Top‐down Chemical Bath Deposition (CBD) method, and the physical properties of the sample are characterized by the X‐ray powder diffraction method (XRD) for phase identification, Scanning electron microscope (SEM) with Energy Dispersive X‐ray Spectroscopy (EDS) for morphology and composition. Synthesized ZrS2 QDs are found to belong to the Trigonal lattice system with a crystalline size 0.58 nm. The Electrochemical performance of the synthesized ZrS2 QDs is studied with the fabricated electrode from Cyclic Voltammetry (CV), Galvanostatic charge and discharge (GCD)/Chronopotentiometry (CP), and Electrochemical Impedance Spectroscopy (EIS) studies. The specific capacitance (Csp), energy density (Ed), and power density (Pd) are calculated with the help of a three‐electrode system. From the CV and GCD/CP, the fabricated electrode material is found to exhibit Faradaic behavior. The synthesized ZrS2 QDs are found to emerge as suitable candidates for electrochemical energy storage applications.

Pressure-induced structural transition of pyrochlore Tm2Sn2O7

The geometrically frustrated pyrochlore Tm2Sn2O7 is an insulator with a slight trigonal lattice distortion at ambient conditions. High pressure was applied to this system to investigate the responses of structural evolution. In-situ angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy analyses have been performed on Tm2Sn2O7 up to 52.6(1) GPa and 62.1(1) GPa, respectively. It was found that Tm2Sn2O7 transformed from the cubic (Fd3̅m) structure to the orthorhombic (Pnma) structure around 36.7(1) GPa. The phase transition was mainly induced by the increased cation disorder upon compression, which efficiently modified its surrounding coordination environment. After releasing pressure, both experimental results revealed that the structural phase transition was reversible.

Evolution of magnetism, valence, and crystal lattice in EuCd2As2 under pressure

${\mathrm{EuCd}}_{2}{\mathrm{As}}_{2}$ has been proposed to be one of the ideal platforms as an intrinsic topological magnetic system, potentially hosting a single pair of Weyl points when it is tuned into the ferromagnetic state with spins aligned out of plane by either external pressure or chemical doping. To investigate the possible realization of an ideal topological state, we have systematically investigated pressure control of the magnetic state, valence, and crystal structure using synchrotron-based time-domain M\"ossbauer spectroscopy, x-ray absorption spectroscopy, and powder x-ray diffraction. Our experimental results show that the magnetic configuration remains mostly in plane under pressure up to 42.8 GPa and pressure effectively enhances the magnetic ordering temperature. Meanwhile, Eu ions remain divalent when subjected to pressure up to 35.9 GPa, and the trigonal crystal lattice is maintained up to 34.6 GPa. Our work provides valuable experimental data to benchmark future theoretical studies in magnetic topological materials.

Ab-initio DFT calculations and experimental investigations into optoelectronic and structural properties of Ca9Al(PO4)7:Sm3+ orange phosphor

Nanocrystalline phosphors of composition Ca9Al(PO4)7:xSm3+ (x = 0.01–0.16) were successfully synthesized using a urea-assisted highly efficient solution combustion technique. The structural, morphological, and photoluminescence features of the series of white powdered samples were studied using powder X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and photoluminescence characterization techniques. The structural framework and crystal phase purity of Ca9Al0.90Sm0.10(PO4)7 phosphor were investigated by Rietveld refinement analysis. The results showed that the replacement of Al3+ ions with Sm3+ ions in Ca9Al0.90Sm0.10(PO4)7 nanophosphor didn't alter the host lattice crystal structure and a trigonal lattice having R3c(161) space group was established. Meanwhile, the average particle size evaluated from the Scherrer equation was further confirmed by transmission electron microscopic studies revealing a size domain ranging from 35-60 nm. Structural optimization of the pure host via first-principle routing disclosed the density of states and electronic band structure having a band gap of 4.738 eV, which was found to be quite comparable to the experimentally observed value (4.37 eV) from the diffuse reflectance spectra. Many key optical properties, such as optical conductivity, extinction coefficient, loss function, and refractive index were determined by using a calculated dielectric function. Furthermore, photoluminescence studies inferred that 10 mol% of Sm3+ ion in Ca9Al(PO4)7 host matrix gave the best luminescence emission intensity. Detailed photoluminescent analysis of Ca9Al(PO4)7:xSm3+ phosphors demonstrated that on excitation at 401 nm, an intense reddish-orange emission was received at 600 nm (4G5/2 → 6H7/2 transition). The critical distance for energy migration came out to be 22 Å which strongly favors the mechanism behind luminescence quenching as dipole-quadrupole interactions resulting from the over-doping of activator ions. The chromaticity coordinates (0.5216, 0.3630) were obtained using MATLAB computations. These results favor the applicability of Sm3+ doped Ca9Al(PO4)7 phosphors as the reddish-orange emitter in near-ultraviolet excited white light-emitting diodes.

Combustion Synthesis and Study of Double Charge Transfer in Highly Efficient Cool White-emitting Dy3+ Activated Vanadate-based Nanophosphor for Advanced Solid-state Lighting.

A series of Ca9Gd(VO4)7: Dy3+ (x = 0.01-0.20) nanophosphor crystals emitting a cool white light were synthesized by solution combustion methodology. The X-ray diffraction patterns were analyzed and processed using Rietveld refinement. The fabricated nanophosphor was found to crystallize in a trigonal crystal lattice with space group R3c(161). The morphological behavior of the prepared nanophosphor was investigated using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The photoluminescence properties of the nanophosphor correspond to cool white emission upon near-ultraviolet (NUV) excitation at 327nm due to 4F9/2 → 6H15/2 (bluish) and 4F9/2 → 6H13/2 (yellowish) radiative relaxations at 487nm and 576nm respectively. Also, there is a strong occurrence of double charge transfer from O2- ions to Dy3+ and V5+ ions with the latter being stronger due to the high positive charge of V5+ ions. Color coordinates (x = 0.2878, y = 0.3259) are consistent with white emission. Auzel's model was implemented to examine the non-radiative relaxation (113.5ms-1), radiative lifetime (1.4856ms), and quantum efficiency (83.13%) values. The crystalline and optical behavior of the synthesized cool white emitting nanophosphor facilitates its use in near-UV-based WLEDs and other advanced solid-state lighting.

Highly Symmetric, Self-Assembling 3D DNA Crystals with Cubic and Trigonal Lattices.

The rational design of nanoscopic DNA tiles has yielded highly ordered crystalline matter in 2D and 3D. The most well-studied 3D tile is the DNA tensegrity triangle, which is known to self-assemble into macroscopic crystals. However, contemporary rational design parameters for 3D DNA crystals nearly universally invoke integer numbers of DNA helical turns and Watson-Crick (WC) base pairs. In this study, 24-bp edges are substituted into a previously 21-bp (two helical turns of DNA) tensegrity triangle motif to explore whether such unconventional motif can self-assemble into 3D crystals. The use of noncanonical base pairs in the sticky ends results in a cubic arrangement of tensegrity triangles with exceedingly high symmetry, assembling a lattice from winding helical axes and diamond-like tessellation patterns. Reverting this motif to sticky ends with Watson-Crick pairs results in a trigonal hexagonal arrangement, replicating this diamond arrangement in a hexagonal context. These results showcase that the authors can generate unexpected, highly complex, pathways for materials design by testing modifications to 3D tiles without prior knowledge of the ensuing symmetry. This study expands the rational design toolbox for DNA nanotechnology; and it further illustrates the existence of yet-unexplored arrangements of crystalline soft matter.

Technological Peculiarities of Epsilon Ferrite Epitaxial Stabilization by PLD

The present paper describes the technological peculiarities relevant to the nucleation and further epitaxial growth of the metastable epsilon phase of iron oxide by means of pulsed laser deposition (PLD). The orthorhombic epsilon ferrite ε-Fe2O3 is an exotic member of a large family of iron oxide polymorphs, which attracts extensive attention nowadays due to its ultra-high magneto-crystalline anisotropy and room temperature multiferroic properties. Continuing the series of previous publications dedicated to the fabrication of ε-Fe2O3 films on GaN, this present work addresses a number of important requirements for the growing conditions of these films. Among the most sensitive technological parameters, the growth temperature must be high enough to aid the nucleation of the orthorhombic phase and, at the same time, low enough to prevent the thermal degradation of an overheated ε-Fe2O3/GaN interface. Overcoming the contradicting growth temperature requirements, an alternative substrate-independent technique to stabilize the orthorhombic phase by mild aluminum substitution is proposed. The advantages of this technique are demonstrated by the example of ε-Fe2O3 films PLD growth carried out on sapphire—the substrate that possesses a trigonal lattice structure and would normally drive the nucleation of the isostructural and energetically more favorable trigonal α-Fe2O3 phase. The real-time profiling of high-energy electron diffraction patterns has been extensively utilized throughout this work to keep track of the orthorhombic-to-trigonal balance being the most important feed-back parameter at the growth optimization stage.

Structure and Magnetism of an Ideal One-Dimensional Chain Antiferromagnet [C2NH8]3[Fe(SO4)3] with a Large Spin of S = 5/2

Isolated large-spin Heisenberg antiferromagnetic uniform chain is quite rare. Here, we have successfully synthesized an ideal one-dimensional (1D) S = 5/2 linear-chain antiferromagnet [C2NH8]3[Fe(SO4)3], which crystallizes in a trigonal lattice with the space group R3c. A broad maximum at Tmax = 18 K is observed in the magnetic susceptibility curve. Notably, no long-range magnetic ordering is observed down to 2 K even if the material has a large Curie-Weiss temperature of θCW = -25.5 K. High-field magnetization at 2 K shows a linear increase until saturation at 30 T, and a high-field electron spin resonance (ESR) reveals the absence of a zero-field spin gap. The intrachain interaction J and interchain interaction J' are determined. Quite a small ratio of J'/J < 2.5 × 10-3 suggests that [C2NH8]3[Fe(SO4)3] behaves as an ideal 1D uniform linear-chain antiferromagnet, in which the magnetic ordering is prevented by the extremely small interchain interaction and quantum fluctuation even for a classical spin of S = 5/2.

NAi/Li Antisite Defects in the Li1.2Ni0.2Mn0.6O2 Li-Rich Layered Oxide: A DFT Study

Li-rich layered oxide (LRLO) materials are promising positive-electrode materials for Li-ion batteries. Antisite defects, especially nickel and lithium ions, occur spontaneously in many LRLOs, but their impact on the functional properties in batteries is controversial. Here, we illustrate the analysis of the formation of Li/Ni antisite defects in the layered lattice of the Co-free LRLO Li1.2Mn0.6Ni0.2O2 compound through a combination of density functional theory calculations performed on fully disordered supercells and a thermodynamic model. Our goal was to evaluate the concentration of antisite defects in the trigonal lattice as a function of temperature and shed light on the native disorder in LRLO and how synthesis protocols can promote the antisite defect formation.

Phonon-induced rotation of the electronic nematic director in superconducting Bi2Se3

The doped topological insulator ${A}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$, with $A={\mathrm{Cu},\mathrm{Sr},\mathrm{Nb}}$, becomes a nematic superconductor below ${T}_{c}\ensuremath{\approx}3$--4 K. The associated electronic nematic director is described by an angle $\ensuremath{\alpha}$ and is experimentally manifested in the elliptical shape of the in-plane critical magnetic field ${H}_{c2}$. Because of the threefold rotational symmetry of the lattice, $\ensuremath{\alpha}$ is expected to align with one of three high-symmetry directions corresponding to the in-plane nearest-neighbor bonds, consistent with a ${Z}_{3}$-Potts nematic transition. Here, we show that the nematic coupling to the acoustic phonons, which makes the nematic correlation length tend to diverge along certain directions only, can fundamentally alter this phenomenology in trigonal lattices. Compared to hexagonal lattices, the former possesses a sixth independent elastic constant ${c}_{14}$ due to the fact that the in-plane shear strain doublet $({\ensuremath{\epsilon}}_{xx}\ensuremath{-}{\ensuremath{\epsilon}}_{yy},\ensuremath{-}2{\ensuremath{\epsilon}}_{xy})$ and the out-of-plane shear strain doublet $(2{\ensuremath{\epsilon}}_{yz},\ensuremath{-}2{\ensuremath{\epsilon}}_{zx})$ transform as the same irreducible representation. We find that, when ${c}_{14}$ overcomes a threshold value, which is expected to be the case in doped ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$, the nematic director $\ensuremath{\alpha}$ unlocks from the high-symmetry directions due to the competition between the quadratic phonon-mediated interaction and the cubic nematic anharmonicity. This implies the breaking of the residual in-plane twofold rotational symmetry (${C}_{2x}$), resulting in a triclinic phase. We discuss the implications of these findings for the structure of nematic domains, for the shape of the in-plane ${H}_{c2}$ in ${A}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$, and for the presence of nodes inside the superconducting state.

Pressure-induced emission enhancement and bandgap narrowing: Experimental investigations and first-principles theoretical simulations on the model halide perovskite Cs3Sb2Br9

We report high-pressure photoluminescence, Raman scattering, and x-ray diffraction measurements on a lead-free halide perovskite ${\mathrm{Cs}}_{3}{\mathrm{Sb}}_{2}{\mathrm{Br}}_{9}$. At about 3 GPa, an electronic transition manifests itself through a broad minimum in linewidth, a maximum in the intensity of ${E}_{g}$, ${A}_{1g}$ Raman modes, and the unusual change in the $c/a$ ratio of the trigonal lattice. The large compressibility and observed Raman anomalies indicate to a soft material with strong electron-phonon coupling. The observed below-bandgap broadband emission in the photoluminescence measurement indicates the recombination of self-trapped excitons. The initial blueshift of the photoluminescence peak reinforces itself to the redshift at around 3 GPa due to the change in the electronic landscape. A first-order trigonal to a monoclinic structural transition is also seen at 8 GPa. The first-principles density functional theory (DFT) calculations reveal that the electronic transition is associated with direct-to-indirect bandgap transition due to changes in the hybridization of $\text{Sb-5}s$ and $\text{Br-4}p$ orbitals near the Fermi level in the valence band. The experimentally observed Raman modes are assigned to their symmetry using the density functional perturbation theory. In addition, the DFT calculations predict a 27.5% reduction of the bandgap in the pressure range 0--8 GPa.

Orbital design of flat bands in non-line-graph lattices via line-graph wave functions

Line-graph (LG) lattices are known for having flat bands (FBs) from the destructive interference of Bloch wavefunctions encoded in pure lattice symmetry. Here, we develop a generic atomic/molecular orbital design principle for FBs in non-LG lattices. Based on linear-combination-of-atomic-orbital (LCAO) theory, we demonstrate that the underlying wavefunction symmetry of FBs in a LG lattice can be transformed into the atomic/molecular orbital symmetry in a non-LG lattice. We illustrate such orbital-designed topological FBs in three 2D non-LG, square, trigonal, and hexagonal lattices, where the designed orbitals faithfully reproduce the corresponding lattice symmetries of checkerboard, Kagome, and diatomic-Kagome lattices, respectively. Interestingly, systematic design of FBs with a high Chern number is also achieved based on the same principle. Fundamentally our theory enriches the FB physics; practically it significantly expands the scope of FB materials, since most materials have multiple atomic/molecular orbitals at each lattice site, rather than a single s orbital mandated in graph theory and generic lattice models.

Mutual Orientation of Electric Intracrystalline and Magnetic Fields in Iron Borate Single Crystals

X-ray structural analysis, Mössbauer spectroscopy, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ab initio</i> calculations are used to study the structural properties and refine the orientation of intracrystalline fields in FeBO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> crystals in the region of the magnetic phase transition. It is found that in the temperature range of 293–403 K, the trigonal lattice parameters increase monotonically. Analysis of the electron density distribution maps does not show visible local disordering over the entire investigated temperature range. It is found that iron borate has an axially symmetric electric field gradient (EFG) whose main axis is directed along [001]. This orientation is maintained above and below the Néel point. In the magnetically ordered state of the crystal, the main axis of the EFG is orthogonal to the direction of the hyperfine magnetic field at iron nuclei. The results obtained will be used to develop a theoretical model of the formation of hyperfine structure in iron borate, which is important for applications of such crystals in next-generation synchrotron technologies.

Highly Efficient and Thermally Stable Eu2+-Doped Ca9Nd(PO₄)7 Phosphor for Near-Ultraviolet White-Emission LED Applications.

Various Eu2+-based Ca9Nd(PO₄)7 (CNP:xEu2+, with different x values) materials are prepared via facile solid-state reaction. Their crystal structures are investigated in detail by means of the Rietveld refinement. The structure of CNP:Eu2+ with a trigonal lattice is analogous to that of β-Ca₃(PO₄)₂. Therefore, Eu2+ ions tend to incorporate calcium sites in the host. All the obtained samples can be excited using near ultraviolet (nUV) light to present blue-green emission. An optimal dopant concentration is verified at x = 0.8 with a large critical interaction radius (11.21 Å). The mechanism of the concentration quenching effect is assigned to the multipole-multipole interaction. CNP:xEu2+ possesses a short decay lifetime of ∼60 μs and can endure severe working conditions thanks to its great thermal stability. The relative photoluminescence (PL) intensity of CNP:0.8Eu2+ can retain 84.75% of the pristine intensity measured at room temperature, and the relative intensity remains as high as 69.97% at 423 K. The CNP:Eu2+ phosphors also show great performance in the WLED demonstration. The correlated color temperature (CCT) of the prototype device is 3404 K, with an extremely high Ra (97.6). Therefore, CNP:xEu2+ could be regarded as a promising alternative to blue green phosphors in nUV chip-based WLED applications.

Crystal chemistry and photoluminescent investigation of novel white light emanating Dy3+ doped Ca9Bi(VO4)7 nanophosphor for ultraviolet based white LEDs

A novel series of white light emitting Ca 9 Bi (1− x ) Dy x (VO 4 ) 7 nanophosphor has been prepared via urea-assisted solution combustion method for the very first time. Structural aspects of the synthesized nanophosphors are investigated by means of X-ray diffraction patterns. The Rietveld refinement performed on host Ca 9 Bi(VO 4 ) 7 and optimal luminescent composition Ca 9 Bi 0.80 Dy 0.20 (VO 4 ) 7 authenticate crystallization in trigonal lattice and space group as R 3 c (161). The emission spectra exhibit peaks due to 4 F 9/2 → 6 H 11/2, 13/2, 15/2 characteristic transitions of Dy 3+ ions on excitation at 389 nm wavelength in ultraviolet region. The band gap for Ca 9 Bi(VO 4 ) 7 has been estimated to be 3.27 eV. The dipole-dipole type interactions are responsible for concentration quenching phenomena in trivalent dysprosium doped Ca 9 Bi(VO 4 ) 7 post 20 mol% composition of dopant ions. The intrinsic lifetime value (0.418 ms) and non-radiative rate (132.27 s −1 ) are determined by employing Auzel's model. The chromaticity coordinates ( x = 0.288, y = 0.338), correlated color temperature (7760 K) and quantum efficiency value (95%) indicate towards a cool and efficient white light emanating Ca 9 Bi 0.80 Dy 0.20 (VO 4 ) 7 nanophosphor. The crystal and optical properties of the prepared nanophosphor vividly define its potential usage as ultraviolet triggered white light emitting source for lighting applications.