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In this work, a simple method to prepare orange-red phosphor is introduced. A series of y at.% Eu3+-doped Gd(Nb x P 1-x)O 4 (x = 0%, 1%, 2%, 3%, 4%, 5%, 6%, 10% and y = 5%, 7%, 9%, 11%, 13%, 14%, 15%) phosphors were prepared through solid reaction technique. The structure and optical properties of the phosphors were characterized using measurements of X-ray powder diffraction, photoluminescence excitation, photoluminescence and decay curves. The X-ray diffraction results revealed that the obtained phosphors possessed the same pure monoclinic phase as GdPO 4 until the doping concentration of Nb5+ reached a maximum value of 5 at.%. With the high sensitivity of the 5D 0 →7F 2 transition to the symmetry of the crystal field, the relative intensity of the two emission peaks at 596 and 615 nm could be continuously adjusted by changing the Nb5+ concentration. Moreover, Judd–Ofelt calculations performed on samples doped with different Eu3+ ions concentrations showed their promise as color-tunable orange-red phosphors. • A series of Eu3+:Gd(Nb x P 1-x)O 4 phosphors with gap type were synthesized. • The energy transfers among Gd3+, NbO 4 3− and Eu3+ were analyzed in detail. • Emission intensity of 596 and 615 nm can be regulated by contents of Nb5+ ions. [ABSTRACT FROM AUTHOR]

A series of fluorescent nanocomplexes of carboxymethyl cellulose (CMC)/Terbium (Tb)- Europium (Eu) were successfully synthesized without introducing a second ligand. By adjusting the concentration of the coordinated ions, these nanocomplexes exhibit favorably visibly tunable luminescence properties with colors being able to change from green to red. The XPS analysis demonstrates the formation Tb(III)-O2− and Eu(III)-O2− between OH and COO− in CMC and Tb3+ or Eu3+ ions, which is advantage for light absorption by UV–Vis spectroscopy and fluorescence spectroscopy. The ligand CMC plays a role in coordinating with terbium and europium ions, but also serves as an energy donor to these metal ions by antenna effect. Moreover, the energy transfer also occurred from terbium ions to europium ions in CMC matrix, which is responsible for the tunable luminescence properties of these complexes. • Color-tunable carboxymethyl cellulose/Tb-Eu nanocomplexes were synthesized. • Antenna effect, the transfer of energy from CMC ligand to Tb3+ or Eu3+. • Energy transfer process from Tb(III) to Eu(III) happened. [ABSTRACT FROM AUTHOR]

A series of novel oxyfluoride borosilicate glass ceramics (GCs) possessing KY 3 F 10 crystalline phase co-doped fixed 0.3 mol% Bi3+ and various Eu3+ from 0 to 1.0 mol% were obtained from the system of SiO 2 –B 2 O 3 –K 2 O-YF 3 -KF-Bi 2 O 3 –Eu 2 O 3 matrix glass. The emission of the GCs was effectively impacted by both the excitation wavelength and Eu3+ concentration. A tunable luminescence from blue to pink can be adjusted by change of Eu3+ concentration from 0 to 1 mol% under excitation of 280 nm for 0.3 mol% Bi3+/у mol% Eu3+ co-doped GCs, while from orange to pink by change of excitation wavelength from 260 to 300 nm for 0.3 mol% Bi3+/1 mol% Eu3+ co-doped GCs. The energy transfer (ET) process from Bi3+ to Eu3+ and the emissions of both Bi3+ and Eu3+ are mainly response for the tunable emission of the GCs. Referring to the fluorescence relative intensity ratio (FIR) between 412 nm (Bi3+:1S 0 →3P 1) and 615 nm (Eu3+:5D 0 →7F 2) determining from temperature-dependent spectra in a wide temperature range of 298–548 K, two crucial parameters of absolute sensitivity (Sa) and relative sensitivity (Sr) of the sample are estimated up to 1.82 % K−1 at 548 K and 3.84 % K−1 at 298 K, respectively. Such high optical temperature sensitivity, widely strong tunable emission and the excellent chemical physical properties endow the GCs a potential candidate for non-contact optical thermometry and multi-color display. • Novel KY 3 F 10 phase structures were investigated by X-ray diffraction. • Eu3+ concentration and excitation wavelength can achieve a wide tunable emission. • This glass ceramics possess high absolute sensitivity and relative sensitivity. • This sample can be potentially used for multicolor display and optical thermometry. [ABSTRACT FROM AUTHOR]

Dy3+/Sm3+ co-doped multicomponent borosilicate glasses were prepared via melt quenching method. The effect of co-doping in the luminescent features of the prepared glasses was analysed using photoluminescent (PL) emission and decay profiles. Variation in PL emission intensity and the lifetime values attributes to the existence of an energy transfer mechanism and is validated the energy transfer route predicted from the spectral overlap diagram. Better luminescent features and CIE chromaticity co-ordinates recommends the present glassy system for lighting applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The researches on cyan phosphors those can be effectively excited by near-ultraviolet (NUV) light are being hot topics lately because that they have potential applications in phosphor converted white light emitting diodes (pc-WLEDs) based on the NUV chips. In this work, Bi3+/Dy3+ doped Ca 2 LaTaO 6 phosphors were prepared through a solid state reaction procedure, and their luminescence characteristics were investigated through the measurements of the luminescence spectra and the decay curves. The excitation spectra indicate that the Bi3+ or Dy3+ single doped and Bi3+/Dy3+ codoped Ca 2 LaTaO 6 phosphors are suitable for NUV excitation due to the excitation spectra within 250–500 nm. The emission spectra show that the lights of Bi3+/Dy3+ codoped Ca 2 LaTaO 6 phosphors locate in cyan region. The ptotoluminescence characteristics indicate that they have possible uses in pc-WLEDs based on NUV chips. • The broad blue emission of Ca 2 LaTaO 6 :Bi3+ phosphors. • The cyan emission of Ca 2 LaTaO 6 :Bi3+/Dy3+ phosphors due to Bi3+.→ Dy3+ energy transfer • The potential applications of Bi3+/Dy3+ doped Ca 2 LaTaO 6 in NUV based pc-WLEDS. [ABSTRACT FROM AUTHOR]

In this work, Tb3+ or Eu3+ single doped and co-doped La 2 W 3 O 12 were synthesized via a solid-state reaction at 900 °C. The crystal structure and photoluminescence properties were systematically investigated in detail. It was found that the La 2 W 3 O 12 based on the advantages of WO 4 groups exhibits a broad absorption cross-section in the ultraviolet area, which can effectively enhance the emission intensity of Tb3+ and Eu3+. The energy transfer from Tb3+ to Eu3+ is determined by the dipole-dipole mechanism, and the energy transfer efficiency from Tb3+ to Eu3+ is as high as 36%. Based on efficient energy transfer effect, multicolor tunable emission from green to yellow and eventually toward red is realized. In addition, the temperature-dependent luminescence of La 2 W 3 O 12 : Tb3+, Eu3+ are carefully investigated, which suggested that as-prepared La 2 W 3 O 12 : Tb3+, Eu3+ phosphors are excellent candidates for solid-state laser, panel display, WLEDs and LED plant lights. [Display omitted] • A prepared novel tungstate Tb3+/Eu3+ co-doped LWO phosphors have good thermal stability and luminescence performance. • The energy transfer mechanism from Tb3+ to Eu3+ was determined to be a dipole-dipole mechanism. • Multicolor tunable emission from green through yellow and eventually to red is realized under UV light excitation. [ABSTRACT FROM AUTHOR]

Tin sulfide (SnS) is an earth-abundance material of non-toxic nature compared to commercially available quantum dots (QDs). Herein, a novel strategy is reported to improve the spectral tunability and stability of SnS/polyvinylpyrrolidone (PVP) core/shell QDs via microwave irradiation synthesis. Although PVP is used as a capping agent and passivating ligand for SnS QDs, as reported elsewhere, we take advantage of its polarity that allows good interaction with microwave irradiation, which impacts the nucleation and growth of SnS QDs. Furthermore, the amount of PVP in the precursor solutions controls the surface states and color purity of the QDs, and the obtained SnS/PVP QDs exhibit color-tunable emission light from blue to orange. The photoluminescence quantum yield reached the highest reported for SnS QDs, whereas 50% of their fluorescence intensity was maintained after 1-year storage at daylight. This approach provides a synthetic route to produce tunable and efficient colloidal QDs. A novel strategy using different polyvinylpyrrolidone (PVP) concentration to control the PVP shell thickness of SnS quantum dot cores, to improve the spectral tunability and stability of SnS/PVP core/shell QDs via microwave irradiation synthesis. With a range of diameters of those SnS/PVP core/shell QDs from 4.29 to 10.53 ​nm [Display omitted]. • Tuning of SnS QDs size by increasing PVP amount in microwave synthesis. • Color-tunable emission from blue to orange light under UV light by SnS/PVP QDs. • FRET is achieved through coupling the PVP chains with SnS cores, reached a high quantum yield. • The optimized PVP thickness gives high color purity and stability of SnS/PVP QDs. [ABSTRACT FROM AUTHOR]

Researches on tunable luminescence and temperature sensitivity of phosphors have become an increasingly popular trend. This paper reports a series of Ca 2 YZr 2 Al 3 O 12 (CYZA):Bi3+, Sm3+ phosphors prepared by solid-state reaction. The phase purity, energy transfer, luminescent properties and temperature sensing performance of the phosphors have been carefully studied. CYZA:Bi3+, Sm3+ phosphors excited by ultraviolet light show tunable color emission, and the color shifts from dark blue to pink due to Bi3+→Sm3+ energy transfer. The related luminescent mechanism of phosphors is also explained. In addition, according to the different thermal sensitivity of Bi3+ and Sm3+, the temperature sensitivity of the phosphors is studied by fluorescence intensity ratio model. The maximum values of absolute sensitivity and relative sensitivity reach up to 0.099% K−1 at 423 K and 0.356% K−1 at 473 K, respectively. These findings indicate that CYZA:Bi3+, Sm3+ phosphors are potential candidates for tunable luminescence and temperature sensing. • The color-tunable property can be obtained in CYZA:Bi3+, Sm3+ phosphors. • Energy transfer from Bi3+ to Sm3+ ions. • Different thermal attenuation behaviors of Bi3+ and Sm3+ ions. • Temperature sensing performance is investigated by FIR model. [ABSTRACT FROM AUTHOR]

A versatile three-dimensional four-fold interpenetrated metal-organic framework [Zn5(btz)6(bdc)2(H2O)2]·7DMA (1) has been synthesized under solvothermal condition, which has two types of channels running along a and b axes with dimension of approximately 7.5×9Å2 and 8.5×11Å2. With the appropriate and permanent porosity, compound 1 exhibits high adsorption of CO2 and good capability to encapsulate Alq3 (tris(8-hydro-xyquinoline)aluminum) chromophores to realize tunable fluorescence at solid state. To the best of our knowledge, this material is a rare example of MOFs that exhibit good capability to tune luminescence properties of Alq3. [ABSTRACT FROM AUTHOR]

All-inorganic perovskite (CsPbX 3 , X = Cl, Br, and I) quantum dots (PQDs) are new stars of semiconductor optoelectronic materials with superior optical properties. However, due to the ionic nature of crystal structure, the stability of PQDs is relatively poor, which seriously hinders their practical application. Herein, the strontium hydroxyapatite (SrHAp) with mesoporous structure and defect-luminescence properties has been introduced as inorganic matrix material to modify the surface of CsPbBr 3 QDs. A series of novel CsPbBr 3 @SrHAp nanocomposites have been prepared by a simple room-temperature synthesis approach for the first time. The CsPbBr 3 @SrHAp nanocomposites not only enhance the green light emission of the CsPbBr 3 QDs, but also realize the color-tunable luminescence from blue through cyan and eventually toward green emission by simply adjusting the relative composition of CsPbBr 3 @SrHAp. Meanwhile, the thermal stability of CsPbBr 3 QDs in the nanocomposites is dramatically improved by incorporating the SrHAp matrix. Furthermore, the as-obtained LED device by combining the CsPbBr 3 @SrHAp nanocomposite and 365 nm LED chip can exhibit dazzling green light emission, which indicates potential prospects and applicability of the nanocomposites for lighting and display devices. Image 1 • A series of novel CsPbBr 3 @SrHAp nanocomposites were prepared by a simple approach. • The CsPbBr 3 @SrHAp nanocomposites enhance the green light emission of the CsPbBr 3 QDs. • The nanocomposites realize color-tunable luminescence from blue to green emission. • The thermal stability of QDs is greatly improved by incorporating the SrHAp matrix. • The CsPbBr 3 @SrHAp nanocomposites may be potentially applied in lighting and displays. [ABSTRACT FROM AUTHOR]

• Novel Pr3+ doped tungsten base-glasses were fabricated. • Heavy glasses with high density up to 6.15 g/cm3. • The characteristic emission around 602 nm (1D 0 →3H 4) of Pr3+ ion • The tunable luminescence property of glass controlled by the excitation sources. Pr3+ doped WO 3 -Gd 2 O 3 -B 2 O 3 glasses were prepared by the melt quenching technique to study in the luminescence under different excitation. X-ray diffraction (XRD) pattern represents the dominant vitreous disordered structure. The glass with 2.0 mol% of Pr 2 O 3 possess a massive density at 6.15 g/cm3. The luminescence spectra of Pr3+ doped glasses were recorded under the various excitation wavelengths of visible light and under the electron excitation. The streak camera was used to measure decay time. The developed glasses show tunable luminescence property, orange under 435 and 447 nm excitation, yellow under 471 and 484 nm excitation and white under the electron excitation. The photo- and catodoluminescence decay times of glasses are comparable. The optimal concentration of Pr 2 O 3 in the glass is 0.1 mol% that performed the highest emission intensity. This glass can be considered as a new low-cost alternative for the tunable light source and the electron detection material. [ABSTRACT FROM AUTHOR]

• Effective regulation of Ce:YAG ceramics by Sc3+ substituting in Al3+ site. • High thermal stability (~6% loss, 150 °C) and high quantum efficiency of 84.2%. • Spectral property of ceramics presented a 21 nm blueshift and decreased Stokes shift. • Tunable optoelectronic performance for ceramic-based WLED/LD. Realizing the high brightness solid-state lighting with the emission spectra similar to that of sun light is significantly challenged by the inherent deficiency of the luminescence spectrum and thermal robustness in the single sturctured Ce3+:Y 3 Al 5 O 12 (Ce:YAG) transparent ceramic (TC). In this study, based on the idea of energy band engineering, the energy splitting intensity of 5d level and the energy gap between the ground band and the 5d1 energy level of Ce3+ ion in Ce:YAG TC were effectively modified via Sc doping. A series of Ce:Y 3 Al 5− x Sc x O 12 (Ce:YASG) TCs were fabricated with impressive properties, showing a decreased stokes shift and a distinct blue-shift (541 → 520 nm) with broadened full width in emission spectra. Particularly, the prepared TCs exhibited a desired thermal stability (only ~6% luminescent intensity loss at 150 °C) and high internal quantum efficiency (IQE) of 84.2%. The optimal composition between Ce3+ and Sc3+ ions was investigated by constructing the Ce:YASG and (Y 1− y Ce y) 3 Al 4 ScO 12 (YCASG) TC-based white LEDs/LDs in a remote excitation mode. Both the luminous efficiency of radiation (LER) as high as 218 lm/W and tunable color from pale-green (pale-white) to yellowish white (pale-green) region were obtained. Therefore, the Ce:YASG TC is a highly promising color conversion material for high power lighting and displaying applications in the future. [ABSTRACT FROM AUTHOR]

• New solid solutions Ca 8 M Tb 1 –x Eu x (PO 4) 7 (M = Mg2+, Zn2+, Ca2+; 0 ≤ x ≤ 1) were synthesized and studied in detail. • The highest integral intensity was registered for Zn doped host and increases the luminescence intensity by 15%. • The effective energy transfer from Tb3+ → Eu3+ was detected and characterized. • Synthesized samples are perspective single-phase phosphors. A series of Ca 8 M Tb 1 –x Eu x (PO 4) 7 (M = Mg2+, Zn2+, Ca2+; 0 ≤ x ≤ 1) with β-Ca 3 (PO 4) 2 -type structure have been synthesized via a standard solid-state method. X-ray diffraction, second harmonic generation, photoluminescence emission and excitation spectra, and decay time curves were used to characterize solid solutions. The color coordinates of as -prepared samples can be shifted from green to red regions by the increasing of Eu3+ concentration. Red-to-orange (R/O) and green-to-blue (G/B) factors indicate a higher local symmetry of emitting Eu3+ and Tb3+ ions environment in Ca 8 M Tb 1– x Eu x (PO 4) 7 (M = Mg, Zn) in comparison to Ca 9 Tb 1 –x Eu x (PO 4) 7. The study shows that Zn-incorporation in the β-Ca 3 (PO 4) 2 matrix increases the luminescence intensity by 15%. The presented results indicate that the synthesized solid solutions can be considered as new single-phase phosphors. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) were prepared by a simple hydrothermal method using citric acid, potassium persulfate, and trishydroxymethylaminomethane as precursors. By adjusting reaction temperature, surface defects of the prepared CDs are modulated. The CDs emit green, yellow, and red fluorescence under the irradiation of a 365 nm ultraviolet lamp. In addition, the CDs are nearly spherical particles and have high stability in aqueous solution, and good biocompatibility, and thus have been applied successfully as a sensor to selectively detect Hg2+ and as a fluorescent bioimaging reagent. • A facile approach for synthesis of carbon dots (CDs) with tunable luminescence is developed. • The surface defects of the CDs can be tailored by adjusting the hydrothermal temperature. • Fluorescence properties of the CDs depend on degree of surface defects of the CDs. • The CDs are used as fluorescence probe to selectively/sensitively detect Hg2+ and cell imaging. [ABSTRACT FROM AUTHOR]

Research process of phosphors with color-tunable luminescence properties has been a research hotspot in the field of high-quality white light emitting diodes. Herein, this paper report that a series of Tb3+ doped and Tb3+, Eu3+ co-doped Ca 2 YZr 2 Al 3 O 12 phosphors were successfully prepared by the traditional solid-state reaction in air atmosphere. The crystal structure, optical performance and thermal quenching behavior were investigated in detail. CYZA: Tb3+, Eu3+ phosphors exhibited tunable color emission from green to yellow to red on the basis the energy transfer of Tb3+→Eu3+ under n-UV excitation. More impressively, as-prepared samples possess high thermal stability comparable or even superior to Lu 3 Al 5 O 12 : Ce3+ via designing the ratio of Tb3+/Eu3+ based on energy transfer. Influence mechanism of Eu3+ on the thermal stability of CYZA: Tb3+ was illustrated. The as-fabricated w-LED device shows a warm white light with high CRI (86.4) at CCT of 3431K. These results suggest its great potential as an excellent luminescent material for the design of warm white solid-state lighting. • CYZA: Tb3+, Eu3+ phosphors were prepared for the first time by solid-state reaction route. • The emitting-color of CYZA: Tb3+, Eu3+ was tunable by adjusting ratio of Tb3+/Eu3+. • The introduction of Tb3+ significantly improves thermal stability, Eu3+ does the opposite. • The mechanism of Tb3+.→Eu3+ energy transfer was investigated. [ABSTRACT FROM AUTHOR]

A series of blue-green emitting NaBaBO 3 :Ce3+, Tb3+ phosphors were synthesized via conventional high temperature solid-state reaction method. The crystal structure, luminescence properties, energy transfer processes and the properties of the packing LED device were investigated. The phosphors present tunable luminescence in the blue-green region due to the energy transfer from Ce3+ to Tb3+. The internal quantum efficiency (IQE) and external quantum efficiency (EQE) of the composition optimized NaBaBO 3 :0.01Ce3+, 0.03 Tb3+ phosphor reached 57% and 36%, respectively. Using a 365 nm NUV LED chip combining with NaBaBO 3 : 0.01Ce3+, 0.03 Tb3+ phosphor and CaAlSiN 3 :Eu2+ red phosphor, a high quality white light was obtained with CIE chromaticity coordinates of (0.316, 0.307), CCT of 6473 K, and CRI of 81.4. These results demonstrated that NaBaBO 3 :Ce3+,Tb3+ phosphors is a promising blue-green phosphor for NUV white LEDs. • The energy transfer of Ce3+→Tb3+ in NaBaBO 3 phosphors has been confirmed. • Quantum efficiency has been calculated. • The emission colors can be varied from blue to blue-greenish through controlling Tb3+ concentrations. • Potential candidates to be used as blue-green phosphor for NUV excited white LEDs. [ABSTRACT FROM AUTHOR]

A series of lanthanide activator ions (Ln3+) doped bismuth silicate Bi 4 Si 3 O 12 phosphors have been fabricated via the Pechini sol−gel route. The as-synthesized eulytite structured Bi 4 Si 3 O 12 sample which exhibits intense green-blue emission is beneficial for host materials of lanthanide activator ions. When the Ln3+ ions (Sm3+, Dy3+, or Eu3+) are doped into the Bi 4 Si 3 O 12 host, an insufficient energy transfer occurs from the host matrix to Ln3+ ions, which can be confirmed by the photoluminescence spectra and decay lifetimes of the Ln3+ doped samples. The as-synthesized Bi 4 Si 3 O 12 :Ln3+ phosphors show both the intrinsic broad band luminescence of Bi 4 Si 3 O 12 host and the characteristic sharp peak emissions of Ln3+ ions, which can generate the tunable multicolor emissions in a single-phase phosphor by adjusting the Ln3+ doping concentrations. More importantly, three kinds of Ln3+-doped single-phase white light emitting phosphors with excellent chromaticity coordinate (x, y) and CCT in the warm white region [Sm3+: (0.336, 0.330), 5315 K; Dy3+: (0.330, 0.370), 5614 K; Eu3+: (0.340, 0.307), 5034 K] can be obtained when the doping concentrations of Sm3+, Dy3+, and Eu3+ are fixed at 0.5, 5, and 1 mol%, which are quite close to the daily use of pure white light. By integrating the Bi 4 Si 3 O 12 :Ln3+ phosphors into a 280 nm UV LED chip, all the fabricated WLED devices can exhibit bright white light emission, which provides direct evidence that the as-synthesized BSO:Ln3+ (Ln = Sm, Dy, and Eu) single-phase white-emitting phosphors have great potential for WLEDs and optoelectronic devices. Image 1 • A series of Ln3+ doped Bi 4 Si 3 O 12 phosphors have been fabricated via a sol-gel route. • An insufficient energy transfer occurs from the Bi 4 Si 3 O 12 host matrix to Ln3+ ions. • The single-phase Bi 4 Si 3 O 12 :Ln3+ phosphors can generate tunable multicolor emissions. • Three white light phosphors can be obtained with good CIE coordinate and CCT. • The WLED devices fabricated by the phosphors can exhibit bright white light emission. [ABSTRACT FROM AUTHOR]

Sm3+, Tb3+ and Sm3+/Tb3+ doped Ba 3 MgSi 2 O 8 phosphors were prepared by molten salts synthesis technique using NaCl/KCl mixture as the flux. The phase and optical characteristics of the prepared phosphors were researched. The XRD results revealed that the prepared phosphors have the pure Ba 3 MgSi 2 O 8 phase. For Sm3+ or Tb3+ singly doped Ba 3 MgSi 2 O 8 phosphors, they show characteristic emission bands of Sm3+ (exciting at 405 nm) or Tb3+ (exciting at 233 nm) ions. Exciting at 233 nm, Sm3+/Tb3+ codoped Ba 3 MgSi 2 O 8 phosphors show emission band corresponding to Sm3+ and Tb3+ ions. Tb3+ → Sm3+ energy transfers occur in Sm3+/Tb3+ codoped Ba 3 MgSi 2 O 8 phosphors, which leads to the tunable luminescence of them. The CIE coordinates change from (0.431, 0.515) for Ba 3 MgSi 2 O 8 :0.12 Tb3+/0.01Sm3+ to (0.555, 0.425) for Ba 3 MgSi 2 O 8 :0.12 Tb3+/0.05Sm3+. The color of light changes from green-yellow for Ba 3 MgSi 2 O 8 :0.12 Tb3+/0.01Sm3+ to red-yellow for Ba 3 MgSi 2 O 8 :0.12 Tb3+/0.05Sm3+. • Molten salts preparation of Sm3+, Tb3+ and Sm3+/Tb3+ doped Ba 3 MgSi 2 O 8 phosphors. • Energy transfer from Tb3+ to Sm3+ in Sm3+/Tb3+ codoped Ba 3 MgSi 2 O 8 phosphors. • Tunable luminescence of Sm3+/Tb3+ codoped Ba 3 MgSi 2 O 8 phosphors. [ABSTRACT FROM AUTHOR]

Uniform and well-dispersed YBO 3 microcrystals with a variety of morphologies (cuboids, cubes, flat quadrilateral particles, etc.) have been synthesized via an easy-to-operate two-step method. During the synthesis process, the well-defined Y(B(OH) 4)CO 3 precursors with diverse shapes were fabricated by a facile wet-chemical method at ambient pressure, without any template, substrate, or catalyst. Finally, the YBO 3 microcrystals which inherit the morphology and dispersity were obtained after a calcination process. The morphology and particle size of the Y(B(OH) 4)CO 3 and YBO 3 microcrystals can be tuned in a controlled manner by simply changing the auxiliary solvent or reaction temperature and time. Upon UV or NIR excitation, the as-synthesized lanthanide ions (Eu3+, Tb3+, Eu3+/Tb3+, Yb3+/Er3+) doped YBO 3 samples exhibit the intense characteristic down-conversion or up-conversion multicolor emissions. The dependence of luminescence intensity on different morphologies and crystallinity has also been studied. This facile synthesis strategy may be of significance for the design and preparation of other lanthanide orthoborates functional materials with well-defined morphologies. Image 1 • A variety of YBO 3 microcrystals with multiform morphologies have been synthesized. • The phase structure, morphology, and luminescence properties were investigated. • The morphology can be tuned in a controlled manner by changing reaction conditions. • The Ln3+ doped samples exhibit intense characteristic DC or UC multicolor emissions. • Dependence of luminescence intensity on morphologies and crystallinity was studied. [ABSTRACT FROM AUTHOR]

A series of emission-tunable Ba 3- x Sc(BO 3) 3 : x Eu2+ (0 ≤ x ≤ 0.15) and Ba 2.97- y Gd y Sc 1- y Mg y (BO 3) 3 : 0.03Eu2+ (0 ≤ y ≤ 0.15) phosphors were synthesized by a solid-state method. Structure analysis of X-ray powder diffraction (XRD) and Rietveld refinement show that Eu2+ ions occupy randomly at Ba sites of hexagonal lattice with space group P6 3 cm. Photoluminescence emission spectra and the decay curves of phosphors demonstrated the existence of multiple Eu2+ emitting centers. Eu2+ ions occupy at four Ba sites of Ba 3- x Sc(BO 3) 3 : x Eu2+ (0.03 ≤ x ≤ 0.15) emit orange light (λem = 670 nm and 560 nm) through 370 nm UV excitation. The broader absorption band, ranging from 220 nm to 550 nm, matches well with the near-ultraviolet LED chips. Furthermore, color tuning from orange to red is successfully achieve by the double doping of Gd3+-Ba2+ and Mg2+-Sc3+ in Ba 2.97 Sc(BO 3) 3 : 0.03Eu2+. Our results indicate that red emission Ba 3 Sc(BO 3) 3 : Eu2+ phosphors is an ideal candidate for the application in white light-emitting diodes. Image 1 • Eu2+ ions occupied at four Ba sites for Ba 3 Sc(BO 3) 3 :Eu2+ emit orange light. • Broader absorption band (220–550 nm) matches well with the n-UV LED chips. • Decay curves prove the existence of energy transfer among multiple Eu2+ centers. • Color tuning is successfully realized by the Gd3+/Mg2+ double substitution. [ABSTRACT FROM AUTHOR]

A series of novel poly (ionic liquid) based lanthanide hybrid materials POSS-PVIM@[Ln (DBM) 3 ] (Ln = Eu, Tb, Gd, DBM = Dibenzoyl methane, PVIM = Polyvinyl imidazole, POSS = polyhedral oligomeric silsesquioxane.) have been synthesized by the copolymerization of POSS with lanthanide functionalized ionic liquid [Ln (DBM) 3 ]@VIM-PA. The obtained hybrids were characterized by FT-IR, X-ray diffraction, XPS, TGA and luminescence spectroscopy. POSS-PVIM@ [Eu (DBM) 3 ] and POSS-PVIM@[Tb (DBM) 3 ] exhibit the characteristic emission of center ions, which indicate that POSS-PVIM could effectively sensitize Eu3+ and Tb3+. More Especially, the luminescent color can be tuned into white excited at 300 nm UV when the ratio of three different lanthanide cations (Eu3+, Tb3+, Gd3+) is 1:3:3. Furthermore, the luminescence films are also prepared, which shows the uniformity and transparency. Light and thermal stability of these as-obtained samples are also improved due to the long chain structure of polymer and rigid skeleton of POSS. In addition, the fluorescent sensing property of the POSS-PVIM@[Eu (DBM) 3 ] was investigated in detail, which shows selective luminescence quenching effect for Cr 2 O 7 2-−. These results provide meaningful data for the multi-component assembly and responsive luminescent of photo functional hybrids based on Poly (ionic liquid) and lanthanide, which can be expected to have potential application in the luminescent sensor devices. • A novel poly (ionic liquid) based lanthanide hybrid materials POSS-PVIM@ [Ln(DBM) 3 ] are synthesized. • The white-emission was obtained by adjusting the ratio of Ln3+. • Low detection limit of POSS-PVIM@ [Eu(DBM) 3 ] for Cr 2 O 7 2- was 0.68 μM. • Good stability in aqueous environment, fast response time to water samples. [ABSTRACT FROM AUTHOR]

Herein, Ce3+ and Ce3+/Dy3+ co-doped Ca 3 Al 2 O 6 phosphors have been designed and synthesized via a facile citrate-based sol-gel technique, and their structural, photoluminescence properties and energy transfer phenomenon were investigated comprehensively. The XRD analysis indicated that pure Ca 3 Al 2 O 6 phase can be synthesized at low temperature (1000 °C) for merely 2 h. The photoluminescence spectra showed the dominant emission of Ce3+ singly doped phosphors is located in the blue region even at low Ce3+ doping level, which indeed favors the energy transfer from Ce3+ to other luminescent centers. When Dy3+ is co-doped into Ca 3 Al 2 O 6 :Ce3+ phosphors, the remarkable sensitizing effect of Ce3+ on Dy3+ is validated by comparatively analyzing the excitation, emission spectra and average lifetimes of the series of samples. Through the concentration quenching theory, the critical distance between Ce3+ and Dy3+ is calculated to be 13.50 Å. Furthermore, the energy transfer mechanism between them is most likely ascribed to electric dipole-dipole interaction. In virtue of the variation of the emission intensities of Ce3+ and Dy3+, the emitting colors of Ca 3 Al 2 O 6 :Ce3+, Dy3+ phosphors can realize tunable luminescence from deep blue to bluish-white region through controlling the Dy3+ content. Based on these analysis, Ca 3 Al 2 O 6 :Ce3+, Dy3+ phosphors could potentially be applied as a single-phase color-tunable phosphors pumped by near-ultraviolet (n-UV) radiation. • Developed a facile sol-gel method to prepare successfully Ca 3 Al 2 O 6 compound. • The blue emission of as-prepared Ca 3 Al 2 O 6 :Ce3+ phosphors dominates, which favors the energy transfer process. • The possible mechanism for the dominance of blue emission was discussed. • The energy transfer phenomenon in Ca 3 Al 2 O 6 :Ce3+, Dy3+ phosphors was investigated in detailed. • Ca 3 Al 2 O 6 :Ce3+, Dy3+ can serve as a single-phase color-tunable phosphors excited by near-ultraviolet radiation. [ABSTRACT FROM AUTHOR]

A novel red-emitting Na 2 Tb 0.5 (MoO 4)(PO 4):0.5Eu3+ phosphor was successfully synthesized via high temperature solid-state reaction method to explore new red emissions with high thermal stability and high colour purity. The results indicate that the alternating tetrahedrons of [PO 4 ]3- and [MoO 4 ]2- formed in the three-dimensional structure play a decisive role in isolating Tb3+ and Eu3+ ions. This structural isolation increases the concentration quenching of Tb3+ and Eu3+ in single-doped phosphors by more than 50%. In co-doped phosphors, the energy transfer from Tb3+ to Eu3+ was verified by the overlap of luminescent spectra and variations in decay curves. The emission colour of Na 2 Y 1- x - y (MoO 4)(PO 4): y Tb3+, x Eu3+ can be tuned from green to red through the energy transfer process by adjusting the ratio of Tb3+/Eu3+. The emission intensity at 150 °C is 84.7% compared to room temperature, as well as the remarkable correlated colour temperature (2425 K) and high colour purity (95.3%) with CIE chromaticity coordinates (0.654, 0.345) make Na 2 Tb 0.5 (MoO 4)(PO 4):0.5Eu3+ as an incredible red-emitting phosphor for both display devices and warm white lighting applications. Image 1 • This phosphor emits high-purity red light (95.3%), it can therefore be used in display devices. • The remarkable CCT (2425 K) also reveals the application value for warm white lighting. • The emission at 425 K is 84.7% of that at room temperature, demonstrating the excellent thermal stability and providing a reliable red light source. • The energy transfer process has been investigated to evaluate the relationship between decay curves and Eu3+ doping amount. [ABSTRACT FROM AUTHOR]

Fluorescent platforms based on organic molecules have attracted great attention in the field of chemical and biological detection because of their high detection efficiency and sensitivity. Strategies in fluorescent platform design with controlled luminescence properties based on Förster resonance energy transfer, excimer/exciplex formation, and metal‐enhanced fluorescence mechanisms are reviewed herein. Attention is focused on the photophysical processes of fluorescent molecules in their interactions with other components as well as with the target. Color‐ and intensity‐tunable luminescence from energy or electron transfer and the electronic structures of fluorescent molecules are discussed. On the basis of the photophysical properties of fluorescent molecules, their responsive fluorescence signals, which reflect specific inter‐ and intra‐molecular interactions, are particularly effective for chemical and biological detection. Förster resonance energy transfer, excimer/exciplex formation, and metal‐enhanced fluorescence mechanisms are essential in the design and fabrication of fluorescent sensing platforms. Donor–acceptor energy transfer, donor–acceptor charge transfer, and surface plasmon coupling occur in these systems enabling responsive fluorescence properties for chemical and biological detection. [ABSTRACT FROM AUTHOR]

Lighting and display technologies are evolving at tremendous rates nowadays; new device architectures based on new, microscopic building blocks are being developed. Besides high light-emission efficiencies, qualities including low cost, low environmental impact, flexibility, or lightweightness are sought for developing new types of devices. Electrospun polymer fibers represent an interesting type of such microscopic structures that can be employed in developing new functionalities. White-light-emitting fiber mats were prepared by the electrospinning of different dye-doped polymer solutions. Two approaches were used in order to obtain white-light emissions: the overlapping of single-dye-doped electrospun fiber mats, and the electrospinning of mixtures of different ratios of single-dye-doped polymer solutions. Scanning electron microscopy (SEM) was used to investigate the morphologies of the electrospun fibers with diameters ranging between 300 nm and 1 µm. Optical absorption and photoluminescence (PL) were evaluated for single-dye-doped submicronic fiber mats, for overlapping mats, and for fiber mats obtained from different compositions of mixtures. Depending on the ratios of the mixtures of different dyes, the luminance was balanced between blue and red emissions. Commission Internationale de L’Eclairage (CIE) measurements depict this fine-tuning of the colors’ intensities, and the right composition for white-light emission of the submicronic fiber mats was found. [ABSTRACT FROM AUTHOR]

Ultra-long-persistent room temperature phosphorescence (RTP) materials have attracted much attention and present various applications in illumination, displays, and the bioimaging field; however, the persistent RTP is generally from the inorganic phosphor materials to date. Herein, we show that the metal coordination polymers (CPs) could be new types of emerging long-lived RTP materials for potential sensor applications. First, two kinds of Cd-based CPs, Cd(m-BDC)(H2O) (1) and Cd(m-BDC)(BIM) (2) (m-BDC = 1,3-benzenedicarboxylic acid; BIM = benzimidazole), were obtained through a hydrothermal process, and the samples were found to exhibit two-dimensional layered structures, which are stabilized by interlayer C-H···π interaction and π···π interaction, respectively. The CPs show unexpected second-time-scale ultra-long-persistent RTP after the removal of UV excitation, and this persistent emission can be detected easily on a time scale of 0-10 s. The CPs also feature a tunable luminescence decay lifetime by adjusting their coordination situation and packing fashion of ligands. Theoretical calculation further indicates that the introduction of the second ligand could highly influence the electronic structure and intermolecular electron transfer toward tailoring the RTP of the CP materials. Moreover, CP 2 exhibits well-defined pH- and temperature-dependent phosphorescence responses. Therefore, this work provides a facile way to develop new type of CPs with steady-state and dynamic tuning of the RTP properties from both experimental and theoretical perspectives, which have potential applications in the areas of displays, pH/temperature sensors, and phosphorescence logic gates. On account of suitable incorporation of inorganic and organic building blocks, it can be expected that the ultra-long-persistent RTP CPs can be extended to other similar systems due to the highly tunable structures and facile synthesis routes.

Ternary I-III-VI nanocrystals, such as silver indium selenide (AISe), are candidates to replace cadmium- and lead-based chalcogenide nanocrystals as efficient emitters in the visible and near IR, but, due to challenges in controlling the reactivities of the group I and III cations during synthesis, full compositional and size-dependent behavior of I-III-VI nanocrystals is not yet explored. We report an amide-promoted synthesis of AISe nanocrystals that enables independent control over nanocrystal size and composition. By systematically varying reaction time, amide concentration, and Ag- and In-precursor concentrations, we develop a predictive model for the synthesis and show that AISe sizes can be tuned from 2.4 to 6.8 nm across a broad range of indium-rich compositions from AgIn11Se17 to AgInSe2. We perform structural and optical characterization for representative AISe compositions (Ag0.85In1.05Se2, Ag3In5Se9, AgIn3Se5, and AgIn11Se17) and relate the peaks in quantum yield to stoichiometries exhibiting defect ordering in the bulk. We optimize luminescence properties to achieve a record quantum yield of 73%. Finally, time-resolved photoluminescence measurements enable us to better understand the physics of donor-acceptor emission and the role of structure and composition in luminescence.

A novel approach to modulating the chemical state of dopants by engineering the topological features of a glass matrix is presented. The method allows selective stabilization of dopants on a wide range of length scales, from dispersed ions to aggregated clusters to nanoparticles, leading to various intriguing optical phenomena, such as great emission enhancement and ultra-broadband optical amplification., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)