New Highly Luminescent Red Emitting Complexes: Synthesis, Characterization, Judd-Ofelt Intensity Parameters and Pharmacological Investigations.

A series of new red luminescent Eu(III) complexes were integrated by ß-hydroxyketone ligand 2-(4-chlorophenyl)-1-(2-hydroxy-4,6-dimethoxyphenyl)ethan-1-one (CHDME) as main ligand and 1,10-phenanthroline (phen) or 5,6-dimethyl-1,10-phenanthroline (dmphen) or bathophenanthroline (bathophen) as ancillary ligand. The complexes were synthesised by solution precipitation method. The CHDME is taken as ligand and its analogous Eu(III) complexes were characterized by elemental analysis, FT-IR and 1H-NMR. The photoluminescent properties were also examined in solid state. The Judd-Ofelt intensity parameters (Ω2 and Ω4) and luminescence quantum efficiency (η) of Eu(III) complexes were additionally figured out as per luminescence spectra and decay cure. UV analysis and optical band was also calculated. Computational analysis were carried out and optical band and Judd-Ofelt intensity parameters were determined. Furthermore, the pharmacological activities such as antimicrobial and antioxidant activity of ligand CHDME and its analogous Europium complexes were also examined. The methods used were tube dilution method for calculating antimicrobial activity and DPPH free radical method for antioxidant activity.

Eu3+ -activated red phosphor Ca3 YAl3 B4 O15 with low thermal quenching behaviour.

This paper reports a sequence of a Ca3 YAl3 B4 O15 :xEu3+ red phosphor prepared using a high-temperature solid-state reaction. At the excitation of 396 nm, the samples emitted intense red emission centred at ~623 nm, which could be attributed to the 5 D0 →7 F2 transition of the Eu3+ ion. The results showed that the optimum Eu3+ doping concentration of Ca3 YAl3 B4 O15 :Eu3+ phosphor was x = 80 mol%, and the concentration quenching mechanism of Ca3 YAl3 B4 O15 :Eu3+ red phosphor belonged to the exchange coupling between Eu3+ ions. The Commission Internationale de l'éclairage (CIE) coordinates and colour purity of Ca3 Y0.2 Al3 B4 O15 :0.8Eu3+ were calculated as (0.6375, 0.3476) and 95.5%, respectively. Moreover, the red emission of the obtained phosphor Ca3 YAl3 B4 O15 :0.8Eu3+ exhibited a low thermal quenching behaviour with an intensity retention rate of 92.85% at 150°C. The above results manifest that the Eu3+ -activated Ca3 YAl3 B4 O15 phosphor is predicted to be a promising red luminescent component for white light-emitting diodes.

Pure red upconverted and near-infrared luminescence properties of Er3+ -doped SnO2 nanocrystals for lighting applications.

Tin oxide (SnO2 ) nanocrystalline powders doped with erbium ion (Er3+ ) in different molar ratios (0, 3, 5, and 7 mol%) were prepared using a solid-state reaction technique. These samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible absorption, visible upconversion, and near-infrared luminescence techniques. XRD analysis revealed the tetragonal rutile structure of SnO2 and the average crystallite size was about 32 nm. From Tauc's plots, it was confirmed that the substitution of Er3+ ions into the SnO2 host lattice resulted in the narrowing its band gap. Optical absorption bands at 520 and 654 nm correspond to the 4f electron transitions of Er3+ further confirming visible light absorption. Infrared luminescence spectra showed a broad band centred at 1536 nm which is assigned to the 4 I13/2 → 4 I15/2 transition of Er3+ . Visible upconverted emission spectra under 980 nm excitation exhibit a strong red luminescence with a main peak at 672 nm which is attributed to the 4 F9/2 → 4 I15/2 transition of Er3+ . Power-dependent upconversion spectra confirmed that two photons participated in the upconversion mechanism. Enhancement in the intensities of both visible and infrared luminescence was observed when raising the concentration. The results pave the way for the potential applications of these nanocrystalline powders in energy harvesting applications such as infrared light upconverting layer in solar cells, light emitting diodes, infrared broadband sources and amplifiers, and biological labelling.

Study on the preparation and luminescence properties of SrGe4 O9 :Mn4+ red phosphors for plant illumination.

In this study, SrGe4 O9 :Mn4+ red phosphors for plant illumination were prepared using a high-temperature solid-phase method. The samples were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fluorescence spectroscopy, and other techniques. The phase structure, apparent morphology, and luminescence properties of the SrGe4 O9 :Mn4+ red phosphors were investigated. The results indicated that the dopant Mn4+ was incorporated into the matrix structure by substituting some Ge4+ ions without any changes in the crystal structure of the SrGe4 O9 matrix. The samples comprised micron-scale particles and exhibited high purity and uniform distribution of elements. The SrGe4 O9 :Mn4+ phosphors exhibited relatively strong red light emission at 660 nm under the excitation of a 430-nm blue light, and the luminescence intensity was the highest when the Mn4+ doping amount was 1%. Proper doping of Ti4+ or Sn4+ could effectively improve the luminescence intensity of the SrGe4 O9 :Mn4+ phosphors. The light-emitting diode (LED) device packaging showed that the SrGe4 O9 :Mn4+ red phosphors could be used for plant growth illumination.

Thermally stable red luminescence from Eu3+ -activated telluro zinc phosphate glass under near-ultraviolet light excitation for photonic applications.

Telluro zinc phosphate (TZP) glasses doped with different concentrations of Eu3+ ions were prepared and their physical, structural, and luminescence properties were studied in detail to reveal the utility of the as-prepared glass for white light-emitting diode (w-LED) applications. The broad hump in the diffraction pattern specified the amorphous behaviour of the TZP glass. The various vibrational shoulder linkages were characterized using the Fourier transform infrared (FT-IR) spectroscopy. The optical absorption spectrum was measured in the ultraviolet (UV)-visible (Vis) light region for the Eu3+ -doped TZP (TZPE) glass and the optical band gap was found to be 3.12 eV. Eu3+ -doped TZP glasses showed several emission peaks in the visible region including an intense red emission peak due to the 5 D0 →7 F2 transition under an excitation wavelength of λex  = 393 nm, which was matched with the emitting wavelength of the near-UV LED chip. Commission Internationale de I'Eclairage (CIE) chromaticity coordinates were situated in the red region and nearly matched with the coordinates of the commercial red phosphor (Y2 O3 S:Eu3+ ). The decay profile of the TZPE50 glass exhibited a single exponential fit with a decay time ( τ ) of 1.76 ms. Temperature-dependent photoluminescence (TDPL) studies demonstrate that the as-prepared glass consist of excellent thermal stability. The detailed analysis and results confirmed that the red-emitting TZPE glasses were potential candidates for white-LED and other photonic applications.

Luminescence properties of neodymium, samarium, and europium niobate and tantalate thin films.

Thin films of lanthanide orthoniobate LnNbO4 (LnNO) and orthotantalate LnTaO4 (LnTO), (Ln = Nd, Sm, Eu) were fabricated using the sol-gel method with subsequent spin-coating on the PbZrO3 /Al2 O3 substrate and annealing at 1000°C. X-ray diffraction patterns showed monoclinic M-LnNbO4 or M´-LnTaO4 , which coexists with the orthorhombic or tetragonal phase. X-ray photoelectron spectroscopy demonstrated the presence of Nd3+ , Sm3+ /Sm2+ and Eu3+ /Eu2+ ions. The luminescence properties of polymorphic films were investigated. Excitation spectra of PbZrO3 interlayer represented broad bands at 410 and 550 nm that were assigned to charge transfer bands (CTB). In all films, the CTB broad band at ~275 nm related to charge transfer transition of Ln3+ →O2- and NbO4 3- or TaO4 3- groups. In excitation spectra, 4 I9/2 →4 G5/2 (Nd3+ ), 6 H5/2 →6 P3/2 (Sm3+ ) and 7 F0 →5 L6 (Eu3+ ) transitions (at 585, 402 and 395 nm), respectively were found to be more intense than any other Ln3+ transition. The emission spectra showed narrow and intense bands at 1065, 600, and 614 nm that were ascribed to Nd3+ , Sm3+ , and Eu3+ 4f-f intraconfigurational transitions 4 F3/2 →4 I11/2 , 4 G5/2 →6 H7/2 , and 5 D0 →7 F2 , respectively. The excellent luminescence properties of films make them new potential groups for visible and/or near-infrared applications such as sensors and imaging equipment.

Optical analysis of Sr3 Gd(PO4 )3 :Pr3+ phosphors for lighting applications.

A series of praseodymium (Pr3+ ) ion activated Sr3 Gd(1-x) (PO4 )3 :xPr3+ (0 ≤ x ≤ 2.0 mol%) phosphors were prepared and their structural, compositional and luminescence properties were investigated. The X-ray diffraction profiles indicate that the studied phosphors crystallized into body centred cubic structure and the Pr3+ ions have no influence on Sr3 Gd(PO4 )3 phase. The high-resolution scanning electron microscopy images show the agglomeration of particles that are inter-connected and form irregular shape Sr3 Gd(PO4 )3 structures. The excitation transitions corresponding to Pr3+ :3 H4 → 3 P2,1,0 transitions at 445, 471 and 483 nm, respectively, matched well with the emission of blue-light-emitting diode (LED) chip. The emission spectra show strong reddish-orange luminescence through 1 D2 → 3 H4 transition when excited at 445 nm blue wavelength. The synthesized phosphors have the potential to be used as reddish-orange lighting devices.

Effect of Organic Cation on Optical Properties of [A]Mn(H2POO)3 Hybrid Perovskites.

Hybrid organic-inorganic compounds crystallizing in a three-dimensional (3D) perovskite-type architecture have attracted considerable attention due to their multifunctional properties. One of the most intriguing groups is perovskites with hypophosphite linkers. Herein, the optical properties of six hybrid hypophosphite perovskites containing manganese ions are presented. The band gaps of these compounds, as well as the luminescence properties of the octahedrally coordinated Mn2+ ions associated with the 4T1g(G) → 6A1g(S) transition are shown to be dependent on the organic cation type and Goldschmidt tolerance factor. Thus, a correlation between essential structural features of Mn-based hybrid hypophosphites and their optical properties was observed. Additionally, the broad infrared luminescence of the studied compounds was examined for potential application in an indoor lighting system for plant growth.

Preparation of a Lanthanide-Titanium Oxo Cluster-Polymer Composite by CuI -Catalyzed Click Chemistry.

Incorporating metal clusters within the skeleton of the organic polymers through a click reaction cannot only effectively prepare cluster-polymer composites, but also effectively avoid the cluster aggregation. Herein, an azide-containing lanthanide-titanium oxo cluster of Eu8 Ti10 -N3 (Eu8 Ti10 -N3 =[Eu8 Ti10 (µ3 -O)14 (H2 O)4 (OAc)2 (tbba)30 (paza)4 (THF)2 ]⋅4 THF⋅8 H2 O (1), Htbba=4-tert-butylbenzoic acid, Hpaza=4-azidobenzoate, HOAc=acetic acid, THF=tetrahydrofuran) through an in situ solvothermal reaction of 4-azidobenzoic acid and 4-tert-butylbenzoic acid. Reaction of 1 with PEG (PEG=methoxypoly(ethyleneglycol)alkyne, 2000 g mol-1 ) through CuI -catalyzed click chemistry generates a lanthanide-polymer composite of Eu8 Ti10 -N3 @PEG (2). Investigation with IR, 1 H NMR and ICP-OES of 2 indicates that the structural integrity of 1 is maintained in 2. Study of the luminescent properties of 1 and 2 reveals that the quantum yield of 1 itself basically remains unchanged in 2. Significantly, the formation of 2 cannot only effectively prevent the cluster 1 from aggregation, but also greatly enhance its solubility and adhesion to the substrate. Owing to the solubility and adhesion of luminescent materials being the key to their practical application, present work is thus of great significance for the development of metal cluster-polymer composite luminescent materials.

Excitation Transfer in Hybrid Nanostructures of Colloidal Ag2S/TGA Quantum Dots and Indocyanine Green J-Aggregates.

The regularities of the electron excitations exchange in hybrid associates of colloidal Ag2S quantum dots, passivated with thioglycolic acid (Ag2S/TGA QDs) with an average size of 2.2 and 3.7 nm with Indocyanine Green J-aggregates (ICG) were studied in this work by methods of absorption and luminescence spectroscopy. It was shown that IR luminescence sensitization of Ag2S/TGA QDs with an average size of 3.7 nm in the region of 1040 nm is possible due to non-radiative resonance energy transfer from Ag2S/TGA QDs with an average size of 2.2 nm and luminescence peak at 900 nm using ICG J-aggregate as an exciton bridge. The sensitization efficiency is 0.33. This technique provides a transition from the first therapeutic window (NIR-I, 700-950 nm) to the second (NIR-II, 1000-1700 nm). It can allow high to increase the imaging in vivo resolution.

Luminescence properties of a novel red phosphor 6LaPO4 -3La3 PO7 -2La7 P3 O18 :Eu3.

Eu3+ -doped 6LaPO4 -3La3 PO7 -2La7 P3 O18 red luminescent phosphors were synthesized by co-deposition and high-temperature solid-state methods and its polyphase state was confirmed by X-ray diffraction analysis. Transmission electron microscopy showed the grain morphology as a mixture of rods and spheres. Luminescence properties of the phosphor were investigated and its red emission parameters were evaluated as a function of Eu3+ concentration (3.00-6.00 mol%). Excitation spectra of 6LaPO4 -3La3 PO7 -2La7 P3 O18 :Eu3+ showed strong absorption bands at 280, 395, and 466 nm, while the luminescence spectra exhibited prominent red emission peak centred at 615 nm (5 D0 →7 F2 ) in the red region. CIE chromaticity coordinates of the 6LaPO4 -3La3 PO7 -2La7 P3 O18 :5%Eu3+ phosphor were (0.668, 0.313) in the red region, and defined its potential application as a red phosphor.

Novel pure Ca2 ZnMoO6 composition with white-light luminescence.

Phosphors with composition Ca2 ZnMoO6 were synthesized at temperatures of 800-1200°C using the solid-state method. Analysis of X-ray diffraction patterns of the Ca2 ZnMoO6 powders did not reveal a double perovskite structure. When the synthesis temperature was equal to or higher than 800°C, the synthesized Ca2 ZnMoO6 powders revealed a tetragonal structure (CaMoO4 ) rather than an orthorhombic structure (Ca2 ZnMoO6 ) and the cubic structure (Sr2 ZnMoO6 ) of a double perovskite. The ZnO phase was still observed at a synthesis temperature of 1200°C. The compositions of synthesized Ca2 ZnMoO6 powders differed from the prepared powder, and the Ca2 ZnMoO6 phosphors exhibited some important novel features. First, synthesized Ca2 ZnMoO6 compositions could emit light as a phosphor no activators, called Ca2 ZnMoO6 phosphors. Effect of synthesis temperature on luminescence properties of these Ca2 ZnMoO6 phosphors was readily observed, and some important novel features and properties were noted. Second, the phosphors presented only one broad characteristic emission peak in the visible light region. Third, measurement of the chromaticity diagram of the Ca2 ZnMoO6 phosphors revealed a white-light source. Through analysis, we determined why the synthesized Ca2 ZnMoO6 phosphors had just one broad characteristic emission peak.

Synthesis, Crystal Structures and Luminescence Properties of Three New Cadmium 3D Coordination Polymers.

: The new rigid planar ligand 2,5-bis(3-(pyridine-4-yl)phenyl)thiazolo[5,4-d]thiazole (BPPT) has been synthesized, which is an excellent building block for assembling coordination polymer. Under solvothermal reaction conditions, cadmium ion with BPPT in the presence of various carboxylic acids including (1,1'-biphenyl)-4,4'-dicarboxylic acid (BPDC), isophthalic acid (IP), and benzene-1,3,5-tricarboxylic acid (BTC) gave rise to three coordination complexes, viz, [Cd(BPPT)(BPDA)](BPPT)n (1), [Cd(BPPT) (IP)] (CH3OH) (2), and [Cd3(BPPT)3(BTC)2(H2O)2] (3). The structures of 1, 2, and 3 were characterized by single crystal X-ray diffraction. The IR spectra as well as thermogravimetric and luminescence properties were also investigated. Complex 1 is a two-dimensional (2D) network and further stretched to a 3D supramolecular structure through π-π stacking interaction. The complexes 2 and 3 show 3D framework. The complexes 1, 2, and 3 exhibited luminescence property at room temperature.

Synthesis of 4-Alkyl-4H-1,2,4-triazole Derivatives by Suzuki Cross-coupling Reactions and Their Luminescence Properties.

New derivatives of 4-alkyl-3,5-diaryl-4H-1,2,4-triazole were synthesized utilizing the Suzuki cross-coupling reaction. The presented methodology comprises of the preparation of bromine-containing 4-alkyl-4H-1,2,4-triazoles and their coupling with different commercially available boronic acids in the presence of ionic liquids or in conventional solvents. The obtained compounds were tested for their luminescence properties.

Tuneable luminescence properties of EDTA-assisted ZnS:Mn nanocrystals from a yellow-orange to a red emission band.

Luminescence technology has been improved with the help of semiconductor nanoparticles that possess novel optical and electrical properties compared with their bulk counterpart. The aim of this study was to design semiconductor nanocrystals in their pure (ZnS) or doped form (ZnS:Mn) with different concentrations of Mn2+ ions by a wet chemical route stabilized by ethylenediamine tetra-acetic acid (EDTA) and to evaluate their luminescence properties. The nanocrystals were characterized by physicochemical techniques such as X-ray diffraction (XRD), High-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SEAD), EDS, and ultraviolet (UV)-visible light and photoluminescence (PL) studies. These results showed the presence of cubic phase and spherically shaped nanocrystals. A blue shift with respect to their bulk counterpart was observed. PL emission spectra were observed with a fixed blue peak and the yellow-orange bands were red shifted towards the red region under the same excitation wavelength. The orange-red bands were attributed to the radiation transition of electrons in 3d5 unfilled shells of Mn2+ ions [4 T1 (4 G)-6 A1 (6 S)]; the ZnS matrix varied with Mn2+ concentration. Shift and increase in the intensity of the PL and absorption bands were observed with increase in Mn content. The study showed that Mn2+ -doped ZnS nanocrystal emission bands can be tuned from the yellow-orange to the red regions under a controlled synthesis process and could be used as promising luminescent emitters in the biology field upon functionalization with suitable materials. Further studies on construction with various other materials will be useful for practical applications.

Effect of cooling rate on the microstructure and luminescence properties of Sr2 MgSi2 O7 :Eu2+ ,Dy3+ materials.

Sr2 MgSi2 O7 :Eu2+ ,Dy3+ long afterglow materials were prepared by a high-temperature solid-state reaction method with different cooling rates. The cooling rate had a slight effect on X-ray diffraction patterns and photoluminescence performance, but significantly modified the grain boundaries and long afterglow properties of the Sr2 MgSi2 O7 :Eu2+ ,Dy3+ materials. When the cooling rate was 1°C/min, grains remained intact with clear grain boundaries. As the cooling rate increased from 1°C/min to 5°C/min, some grain boundaries became indistinguishable. The afterglow properties were optimized, presenting best performance at the cooling rate of 3°C/min. The trap state was investigated and illustrated through thermoluminescence curves. The depths of the traps of all the samples were unchanged, whereas densities changed to a large extent, leading to different afterglow properties. The retrapping process is discussed based on the afterglow curves.

Synthesis and photoluminescence characteristics of Sm3+ -doped Bi4 Si3 O12 red-emitting phosphor.

A series of novel red-emitting Sm3+ -doped bismuth silicate phosphors, Bi4 Si3 O12 :xSm3+ (0.01 ≤ x ≤ 0.06), were prepared via the sol-gel route. The phase of the synthesized samples calcinated at 800 °C is isostructural with Bi4 Si3 O12 according to X-ray diffraction results. Under excitation with 405 nm light, some typical peaks of Sm3+ ions centered at 566, 609, 655 and 715 nm are found in the emission spectra of the Sm3+ -doped Bi4 Si3 O12 phosphors. The strongest peak located at 609 nm is due to 4 G5/2 -6 H7/2 transition of Sm3+ . The luminescence intensity reaches its maximum value when the Sm3+ ion content is 4 mol%. The results suggest that Bi4 Si3 O12 :Sm3+ may be a potential red phosphor for white light-emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.

Copper(I) Complexes of N-(2-{[(2E)-2-(4-Nitrobenzylidenyl)Hydrazinyl]Carbonyl}Phenyl)Benzamide and Triphenylphosphine: Synthesis, Characterization and Luminescence Properties.

Copper(I) complexes of the formula [Cu(L)(PPh3)2]X (1-4) (X = Cl(1), ClO4(2), BF4(3) and PF6(4)) [where L = N-(2-{[(2E)-2-(4-nitrobenzylidenyl)hydrazinyl]carbonyl}phenyl)benzamide; PPh3 = triphenylphosphine] have been prepared by the condensation of N-[2-(hydrazinocarbonyl)phenyl]benzamide with 4-nitrobenzaldehyde followed by the reaction with CuCl, [Cu(MeCN)4]ClO4, [Cu(MeCN)4]BF4 and [Cu(MeCN)4]PF6 in presence of triphenylphosphine as a coligand. Complexes 1-4 were then characterized by elemental analyses, FTIR, UV-visible and 1H NMR spectroscopy. Mononuclear copper(I) complexes 1-4 were formed with L in its keto form by involvement of azomethine nitrogen and the carbonyl oxygen along with two PPh3 groups. A single crystal X-ray diffraction study of the representative complex [(Cu(L)(PPh3)2]CIO4 (2) reveals a distorted tetrahedral geometry around Cu(I). Crystal data of (2): space group = C2/c, a = 42.8596 (9) Å, b = 14.6207 (3) Å, c = 36.4643 (7) Å, V = 20,653.7 (7) Å3, Z = 16. Complexes 1-4 exhibit quasireversible redox behaviour corresponding to a Cu(I)/Cu(II) couple. All complexes show blue-green emission as a result of fluorescence from an intra-ligand charge transition (ILCT), ligand to ligand charge transfer transition (LLCT) or mixture of both. Significant increase in size of the counter anion shows marked effect on quantum efficiency and lifetime of the complexes in solution.

Electrospinning preparation and photoluminescence properties of Y3Al5O12:Tb3+ nanostructures.

Novel nanostructures of Y3Al5O12:Tb(3+) (denoted as YAG:Tb(3+) for short) nanobelts and nanofibers were fabricated by calcination of the respective electrospun PVP/[Y(NO3)3 + Tb(NO3)3 + Al(NO3)3] composite nanobelts and nanofibers. YAG:Tb(3+) nanostructures are cubic in structure with a space group of Ia 3d. The thickness and width of the YAG:7%Tb(3+) nanobelts are respectively ca. 125 nm and 5.9 ± 0.3 m, and the diameter of YAG:7%Tb(3+) nanofibers is 166.0 ± 20 nm (95% confidence level). The YAG:Tb(3+) nanostructures emit predominantly at 544 nm from the energy levels transition of (5) D4 → (7) F5 of Tb(3+) ions under the excitation of 274-nm ultraviolet light. It was found that the optimum doping molar concentration of Tb(3+) ions for YAG:Tb(3+) nanostructures was 7%. Compared with YAG:7%Tb(3+) nanofibers, YAG:7%Tb(3+) nanobelts exhibit a stronger photoluminescence (PL) intensity under the same doping concentration. Commission International de l'Eclairage (CIE) analysis demonstrates that the emitting colors of YAG:Tb(3+) nanostructures are located in the green region and color-tuned luminescence can be obtained by changing the doping concentration of Tb(3+) and morphologies of the nanostructures, which could be applied in the field of optical telecommunication and optoelectronic devices. The possible formation mechanisms of YAG:Tb(3+) nanobelts and nanofibers are also proposed.

Current Development of Lanthanide Complexes for Biomedical Applications.

Luminescent molecule-based bioimaging system is widely used for precise localization and distinction of cancer/tumor cells. Luminescent lanthanide (Ln(III)) complexes offer long-lived (sub-millisecond time scale) and sharp (FWHM <10 nm) emission, arising from the forbidden 4f-4f electronic transitions. Luminescent Ln(III) complex-based bioimaging has emerged as a promising option for both in vitro and in vivo visualizations. In this mini-review, the historical development and recent significant progress of luminescent Ln(III) probes for bioapplications are introduced. The recent studies are mainly focused on three points: (i) the structural modifications of Ln(III) complexes in both macrocyclic and small ligands, (ii) the acquirement of high resolution luminescence images of cancer/tumor cells and (iii) the constructions of ratiometric biosensors. Furthermore, our recent study is explained as a new Cancer GPS (cancer grade probing for determining tumor grade through photophysical property analyses of intracellular Eu(III) complex.