Emission Intensity Of Tb3 Research Articles

Energy Transfer in Mixed Lanthanides Complexes: Toward High‐Performance Pressure Sensors Based on the Luminescence Intensity Ratio

AbstractIn this study, a reversible pressure‐sensing material with high sensitivity is presented. Mixed β‐diketonate complexes of Tb3+ and Eu3+ [(Ln)(acac)3phen] are synthesized with phenanthroline as an ancillary ligand. The organic ligands provide the antenna effect to make the Ln3+ complex excitable at 405 nm. Eu3+ emission results from efficient energy transfer (ET) from Tb3+. Under 405 nm excitation, the emission intensity of Tb3+ decreases whereas the emission intensity of Eu3+ increases with pressure, making this complex a potential pressure sensor based on luminescent‐intensity‐ratio (LIR) up to 700 MPa. This study then discusses the application of this Tb3+/Eu3+ complex for pressure sensing depending on measurement conditions. The addition of the optically neutral ion Y3+ to the system can reduce the impact of pressure‐induced structural defects on the emission, thus improving the reversibility of the LIR variation as a function of pressure. Therefore, a self‐calibrating, reliable, and reversible pressure‐sensing material is proposed here, with remarkable pressure sensitivity compared to a peak shift‐based pressure sensor.

Crystallization behavior and up-conversion optical characteristics based on NaZnPO4: Yb3+/Tb3+/Ho3+ nanocrystals embedded in glass matrix

Yb3+/Tb3+/Ho3+ tri-doped transparent glass ceramic (GC) embracing orthorhombic NaZnPO4 nano-particles was triumphantly prepared on the basis of melting quenching and pursuant controllable crystallization approach. The NaZnPO4 nano-crystals were identified by XRD and TEM. The up-conversion (UC) emission intensities of Tb3+ and Ho3+ in the GC grew by more than the forerunner glass counterpart. The crystallization mode of the prepared glass was one-dimensional crystallization mechanism its confirmed by differential thermal analysis. The glass with transmittance of about 90% and the GC with transmittance of about 62–76% maintain comparatively high transparency in the visible light range. The tunable colors of UC luminescence can be carried out by transforming the doping concentration of Tb3+, and energy transfer of Ho3+→Tb3+ exists. The UC luminescence mechanism of GC was proved to be a multiphoton process. Furthermore, the GC sample has great thermal and chroma stability with Chromaticity shift between 4 × 10−3 and 8 × 10−3 in the temperature extent of 298–498 K. The results make clear that the Yb3+/Tb3+/Ho3+ tri-doped NaZnPO4 GC might be promising candidates for advanced UC luminescent materials.

Double nanocrystalline engineering for effective enhanced photoluminescence of Tb3+ in glass ceramic

Despite possessing good feature for optical thermometry, the rare (RE) ions-based temperature sensing (TS) has innate shortcoming of thermally coupled levels (TCLs) energy gap overlap, which reduces the sensitivity. In this work, a dual-luminous centers TS based on Tb3+ doped Cs4PbBr6 quantum dots (QDs) glass ceramic is fabricated. By locating in low phonon energy crystal field environment of Cs2ZnSi5O12 nanocrystalline (NS) and Cs4PbBr6 QDs, the emission intensity of Tb3+ can be enhanced by 14 times. The large exciton binding energy (420 meV) indicates that the prepared QDs glass ceramic has a good thermal stability and the PL intensity of Cs4PbBr6 QDs and Tb3+ can be well-maintained above 70% and 89% after 8 thermal cycles between 323K and 373K. Furthermore, the obtained maximum absolute sensitivity (Sa) and relative sensitivity (Sr) is as high as 0.2541 K-1 and 2.68% K−1, respectively. It is expected that the finding of this work can offer a help in exploring novel QDs/RE ions-based TS and further optimize their practical applications.

A novel aluminum-oxynitride phosphor Mg0·695Si0·695Al1·39O3·65N0.35: Ce3+, Tb3+, Mn2+ based on cation substitution with double sites related multicolor-tunable luminescence

A new aluminum-oxynitride Ce3+-Tb3+ and Ce3+-Mn2+ co-doped Mg0·695Si0·695Al1·39O3·65N0.35 (MSAON) have been prepared by the high-temperature solid-state method at 1500 °C. The structure, photoluminescence properties, energy transfer (ET) mechanism, thermal quenching behaviors have been investigated. The MSAON host has been formed based on the co-substitution method of cation pair. Under UV excitation, the tunable-color emissions from violet to green and red can be realized by properly doping Ce3+/Tb3+/Mn2+ ions. In addition, the type of ET mechanism from Ce3+ to Tb3+ and Mn2+ both are confirmed to be electric dipole-quadrupole interaction. However, as temperature increases, the emission intensity of Tb3+ in MSAON: Ce3+, Tb3+ phosphor occurs a significantly rising trend until 493 K, which is caused by increasing energy transfer from Ce3+ to Tb3+ due to the effect of enhanced electron–phonon coupling with rising temperature. This property may be helpful for the investigation of ratiometric optical thermometry. Meanwhile, the MSAON: Ce3+, Mn2+ phosphor shows an excellent thermal stability, maintaining 84.25% of initial intensity at 423 K. The results suggest that they could be feasible multicolor-tunable emission phosphors for potential applications for near -UV WLEDs.

Luminescence property, energy transfer and thermal stability of Sr6Ca4(PO4)6F2:Ce3+, Tb3+, Sm3+ for white light emitting diodes

Series of Sr6Ca4(PO4)6F2:Ce3+, Tb3+, Sm3+ are prepared by a high temperature solid state method. Ce3+, Tb3+ or Sm3+ single-doped Sr6Ca4(PO4)6F2 can produce blue, green and red emission under ultraviolet excitation, respectively. However, the emission intensities of Tb3+ and Sm3+ are relatively weak due to their forbidden transition. In order to achieve white light, the spectral property and decay curves of Sr6Ca4(PO4)6F2:Ce3+/Tb3+/Sm3+ are measured, not only the energy transfer of Ce3+-Tb3+, Ce3+-Sm3+ and Tb3+-Sm3+ was demonstrated, importantly, but also the single-phase white emitting phosphor Sr6Ca4(PO4)6F2:0.14Ce3+, 0.07Tb3+,0.13Sm3+ was obtained by the energy transfer.

Enhanced luminescence in Tb3+-doped glass-ceramic scintillators containing LiYF4 nanocrystals

Tb3+ ions single-doped transparent oxyfluoride glass-ceramics (GC) containing LiYF4 nanocrystals were prepared via a conventional high-temperature melt quenching way and subsequent further thermal-treatment. The microstructure and related luminescent properties of the composite materials were studied in detail. It was confirmed by XRD and TEM techniques that the precipitated particles in the glass phase of the GC590-4h sample were LiYF4 nanocrystals having a size of approximately 26 nm. Compared to the PG sample, the luminescence intensity of the GCs at 378 nm light excitation was significantly enhanced and the corresponding lifetime was prolonged. This is because the Tb3+ ions are preferentially enriched in the precipitated low-phonon-energy LiYF4 nanocrystals, which can effectively induce the reduction of non-radiative transitions. It is worth noting that the emission intensity of Tb3+ single-doped GCs containing LiYF4 nanocrystals at 545 nm (5D4→7F5) is also greatly improved (under X-ray excitation). The obtained results indicate that Tb3+ single-doped LiYF4 GC may have the potential to be a novel scintillator applied to X-ray detection for the slow event.

Radio, cathodo and photoluminescence investigations of high density WO3-Gd2O3-B2O3 glass doped with Tb3+

The Tb3+ doped tungsten-gadolinium-borate glasses (WGB:Tb) were prepared by the melt-quenching technique with different Tb2O3 concentration (0.0, 0.1, 0.5, 1.0 and 2.0 mol%). Properties of glasses were characterized by such techniques as Archimedes´ method, XRD, absorption spectroscopy, various types of luminescence spectroscopy and decay curves. Glass performs the enhanced compaction with increment of Tb2O3 content. XRD pattern represents the amorphous nature of glass system. Tb3+ in glass absorbs photons in visible light and near infrared region. The strong green emission around 544 nm via 5D4 → 7F5 transition of Tb3+ were generated under three types of excitation such as ultraviolet–visible light (photoluminescence), X-ray (radioluminescence) and electron (cathodoluminescence). The Gd3+ - Tb3+ energy transfer plays an important role for strong green emission of glass. The intensity of this luminescence increases with increment of Tb2O3 concentration. All luminescence decay curves represent in the forms of non-single/multi-component exponential functions. The values of all decay time are in the order of millisecond. Moreover, the emission intensity of Tb3+ reduced with temperature increment (thermal quenching) proved by the temperature-dependent luminescence. In this work, the WGB:Tb glass doped with 2.0 mol% of Tb2O3 is a versatile glass. It is suitable and can be developed for using as a photonic materials in the green light source, laser, display/screen, X-ray detector and scanning/transmission electron microscope.

A LUMINESCENCE PROPERTIES OF Tb, Sm CO-DOPED IN ALKALI ALUMINOBORATE GLASSES

Spectroscopic properties of Tb3+ and Sm3+ ions co-doped in alkali aluminoborate glasses (70-x-y)B2O3.28Li2O.2Al2O3.xSm2O3.yTb2O3 (ABL:Tb,Sm) fabricated by melting method have been studied. The emission intensity of Tb3+ or Sm3+ in ABL:Tb or ABL:Sm glasses is influenced by the Tb3+ or Sm3+ doping content, and the optimum concentrations of Tb3+ and Sm3+ are 0.75 mol% and 1.0 mol%, respectively. The concentration quenching effect of Tb3+ or Sm3+ in ABL:Tb,Sm glasses occurs, and the concentration quenching mechanism is f-f interaction for either Tb3+/Sm3+. The ABL:Tb,Sm glasses can produce color emission from green to red by properly tuning the relative ratio between Tb3+ and Sm3+, the emission intensity of Tb3+/Sm3+ in ABL:Tb,Sm glasses can be enhanced by the energy transfer from Tb3+/Tb3+ and Sm3+/Sm3+. The results indicate that ABL:Tb,Sm may be a promising double emission for white light emitting diodes.

Insight into luminescent properties, energy transfer and thermal stability of NaBa4(AlB4O9)2Cl3:Ce3+, Tb3+ phosphors

AbstractA series of Ce3+ and Tb3+ singly‐ and co‐doped NaBa4(AlB4O9)2Cl3 (NBAC) phosphors have been synthesized via high‐temperature solid state route. The crystal structure, morphology, photoluminescent properties, thermal properties and energy transfer process between Ce3+ and Tb3+ were systematically investigated. The structure refinements indicated that the phosphors based on NBAC crystallized in P42nm polar space group in monoclinic phase. The emission color could be tuned from blue (0.1595, 0.0955) to green (0.2689, 0.4334) via changing the ratio of Ce3+/Tb3+. The energy transfer mechanism of Ce3+/Tb3+ was verified to be dipole–quadrupole interaction via the examination of decay times of Ce3+ based on Dexter's theory. The good thermal stability showed the intensities of Ce3+ at 150°C were about 66.9% and 64.88% in NBAC:0.09Ce3+ and NBAC:0.09Ce3+, 0.07Tb3+ of that at room temperature, and the emission intensities of Tb3+ remained 102.41% in NBAC:0.11Tb3+ and 95.22% in NBAC:0.09Ce3+, 0.07Tb3+ due to the nephelauxetic shielding effect and the highly asymmetric rigid framework structure of NBAC. The maximum external quantum efficiency (EQE) of Ce3+ in NBAC:0.09Ce3+, yTb3+ phosphors could reach 43.38% at y = 0.13. Overall, all the results obtained suggested that NBAC:Ce3+, Tb3+ could be a promising option for n‐UV pumped phosphors.

Efficient energy transfer and luminescence properties of green–blue emission in Ce/Tb Co-doped Sr3NaY(PO4)3F phosphors

Ce3+ and Ce3+/Tb3+-activated Sr3NaY(PO4)3F phosphors are synthesized by the high temperature solid-state reaction, which can be efficiently excited by near ultraviolet (NUV) light-emitting diode (LED) chips. The X-ray diffraction profiles (XRD), photoluminescence(PL) spectra, the decay curves, thermal properties and energy transfer of the phosphors were systematically investigated in detail. The PL spectrum of Sr3NaY(PO4)3F:Ce3+/Tb3+ shows a broad hump ranging from 300 to 450 nm of Ce3+ ions and characteristic line of Tb3+ ions. The emission intensity of Tb3+ increased and that of Ce3+ decreased with the increase of content of Tb3+. The color of the Sr3NaY(PO4)3F:Ce3+/Tb3+ phosphors can shift from blue to green by varying Tb3+ content. The decay curves of Sr3NaY(PO4)3F:Ce3+/Tb3+ indicated that energy transfer process from Ce3+ to Tb3+ existed in the host and the quadrupole–quadrupole interaction to be demonstrated for energy transfer mechanism. In addition, the Sr3NaY(PO4)3F:Ce3+/Tb3+ phosphor exhibits excellent thermal stability, 90% initial emission intensity still remained at temperatures over 100 °C. The obtained results reveal that Sr3NaY(PO4)3F:Ce3+/Tb3+ phosphors can be served as a green-emitting candidate material for phosphor-converted white-light NUV-LEDs.

Efficient energy transfer and fluorescence in SrYAl3O7:Ce3+, Tb3+ phosphor

A green light emitting phosphor SrYAl3O7:Ce3+, Tb3+ have been synthesized by fast solution combustion route. Structural and photoluminescence properties with energy transfer (ET) mechanism were investigated. Due to the ET from Ce3+ to Tb3+, enhancement in the emission intensity of Tb3+ is observed. The prepared phosphors exhibit both the weak emission of Ce3+ (5d–4f) and the strong emission of Tb3+ (5D4–7FJ) with considerable emission intensity. The ET mechanism from Ce3+ to Tb3+ ion has been determined to be dipole–dipole interaction, and the ET efficiency is obtained over 81%. The effect of Ce3+ and Tb3+ concentrations on luminescence intensity in single and co-doped phosphors are also studied. The phosphor has remarkable CIE chromaticity coordinates of (0.198, 0.532), which indicate that Ce3+ and Tb3+ co-doped SrYAl3O7 phosphor may be potential UV-convertible candidate with green light emitting for w-LEDs.

Photoluminescence, energy transfer, color tunable properties of Sr3La(BO3)3:Ce, Tb phosphors

A series of blue-green color tunable Sr3La(BO3)3:Ce, Tb phosphors were prepared via a solid-state reaction method. The characterizations of X-ray diffraction (XRD), photoluminescence properties, the diffuse reflectance spectra (DRS), the decay curves, energy transfer mechanism and color tunable properties were investigated in detail. As Ce3+ ions single doped in Sr3La(BO3)3, the phosphor presents intense light blue under n-UV excitation. As for Sr3La(BO3)3:Ce, Tb, with the increase of the concentration of Tb3+, the emission intensity of Tb3+ characteristic wavelength increased and that of Ce3+ deceased at the same time. By comparing the decay curves of Sr3La(BO3)3:0.03Ce, y Tb, the results indicated that energy transfer existed between Ce3+ and Tb3+, the energy transfer efficiency reached 91.57% when y = 0.5. The energy transfer mechanism from Ce3+ to Tb3+ in Sr3La(BO3)3 was demonstrated to be dipole-quadrupole and the critical distance was calculated to be 7.6295 Å∼10.1741 Å by Dexter's energy transfer theory. Those results indicated that the color tunable Sr3La(BO3)3:Ce, y Tb phosphors can be a potential green-emitting candidate for w-LEDs under n-UV.

Adjustable multicolor up-energy conversion in light-luminesce in Tb3+/Tm3+/Yb3+ co-doped oxyfluorifFde glass-ceramics containing Ba2LaF7 nanocrystals

Transparent oxyfluoride glasses with highly efficient up-energy conversion (UEC) luminescence were developed in the 45SiO2-15Al2O3-12Na2CO3-21BaF2-7LaF3-xTbF3-yTmF3-zYbF3 composition (in mol%), and structural investigation by X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of face-centered cubic Ba2LaF7 nanocrystals. The colors of UEC luminescences could be tuned easily by adjusting the concentration of doped rare earth ions and the excitation power of laser simultaneously. The relationship between the emission intensity of Tb3+/Tm3+/Yb3+ co-doped oxyfluoride glass-ceramics and the excitation pump power revealed that three-photon and two-photon absorptions predominated in the conversion process from the infrared into blue and red luminescences, respectively. A novel UEC mechanism of red emission from Tm3+ was proposed, energy transfers from Yb3+ to Tm3+ and Tb3+ and from Tm3+ to Tb3+ were evidenced. The possible mechanism responsible for the color variation of UEC in Tb3+/Tm3+/Yb3+ co-doped was discussed.

The development of new phosphors of Tb3+/Eu3+ co-doped Gd3Al5O12 with tunable emission

The gadolinium aluminum garnets Gd3Al5O12 (GdAG) activated with Tb3+/Eu3+ were successfully prepared via co-precipitation method at 1500 °C in this work. The crystal structure stabilization, elements analysis, microphotograph, PL/PLE spectra, decay behavior and quantum efficiency were discussed in detail. The metastable GdAG compounds been effectively stabilized by doping with smaller 10 at.% Tb3+, which then allows the development of new phosphors of (Gd0.9-xTb0.1Eux)3Al5O12 (GdAG:Tb3+/Eu3+, x = 0–0.03) for opto-functionality explorations. The PLE/PL spectra displays that the strongest PLE peak was located at ∼276 nm, which overlaps the 8S7/2 → 6IJ transition of Gd3+. Under 276 nm excitation, the phosphors exhibited both Tb3+ and Eu3+ emissions at 548 nm (green, 5D4 → 7F5 transition of Tb3+) and 592 nm (orange-red, 5D0 → 7F1 transition of Eu3+), respectively. The emission intensities of Tb3+ and Eu3+ remarkably varied with the Eu3+ incorporation. As a consequence, the emission color can be readily tuned from approximately green to orange-red. Fluorescence decay analysis found that the lifetime for the Tb3+ emission rapidly decreased conforming to the Tb3+ → Eu3+ energy transfer, and the energy transfer efficiency was calculated. Owing to the Gd3+ → Eu3+ and Gd3+ → Tb3+ energy transfer, the emission intensities of Tb3+ and Eu3+ in (Gd0.9-xTb0.1Eux)AG phosphor were higher than (Y0.87Tb0.1Eu0.03)AG and (Lu0.87Tb0.1Eu0.03)AG system. The (Gd0.9-xTb0.1Eux)AG garnet phosphors developed in this work may serve as a new type of phosphor which hopefully meets the requirements of various lighting and optical display applications.

Luminescence properties and energy transfer from Gd3+ to Tb3+ ions in gadolinium calcium silicoborate glasses for green laser application

Abstract The Tb 3+ -doped gadolinium calcium silicoborate (BSGdCaTb) glasses of composition (55-x) B 2 O 3 - 10 SiO 2 - 25 Gd 2 O 3 -10 CaO -x Tb 2 O 3 , where x = 0.01, 0.05, 0.1, 0.5, 1.0, and 2.0 mol %, have been prepared by conventional melt quenching technique and are characterized through thermal, absorption, excitation, emission and decay rate measurements. The optical band gap (E opt ) and Urbach's energies (ΔE) have been evaluated taking into account the ultraviolet (UV) edge of absorption spectra. The Tb 3+ -doped BSGdCaTb glasses exhibit strong emission in the green ( 5 D 4 → 7 F J , J = 3,4,5 and 6) and very weak emission in the ultraviolet blue ( 5 D 3 → 7 F J , J = 3,4,5 and 6) transitions under excitation at 275 nm, respectively. The intensity of the 5 D 4 → 7 F 5 (green at 543 nm) and 5 D 3 → 7 F 4 (blue at 436 nm) emissions and their integrated intensity ratios (I G /I B ) and (I B /I G ) under 275 nm excitation have been obtained as a functions of Tb 3+ concentration, respectively. The emission intensity of Gd 3+ at 312 nm decreases with increasing of Tb 2 O 3 concentration, while emission intensity of Tb 3+ increases upto 1.0 mol % concentration of Tb 2 O 3 . The Tb 3+ ion decay time for 5 D 4 level has been determined and is found to be slightly decreases with increasing of Tb 2 O 3 concentration. The CIE color coordinates and color purity have been calculated for Tb 3+ -doped glasses and it have found to be shift towards the bright green region with increasing of Tb 3+ ion concentration in BSGdCaTb glasses.

High thermal stability and quantum yields of green-emitting Sr3Gd2(Si3O9)2:Tb3+ phosphor by co-doping Ce3+

A series of Tb3+ mono-doped and Ce3+-Tb3+ co-doped Sr3Gd2(Si3O9)2 phosphors with high thermal stability and quantum yields were successfully prepared via the solid state reaction. The as-prepared Sr3Gd2(Si3O9)2:Tb3+ samples showed broad excitation spectrum from 250 to 400 nm and presented characteristic emission transitions 5D4→7FJ (J=6, 5, 4, 3) of Tb3+ under 313 nm excitation, which were located at about 488, 541, 584 and 620 nm. The emission intensities of Tb3+ rose steadily in Sr3Gd2(Si3O9)2 host with the increase of Tb3+ concentration even though Gd3+ ions were completely replaced by Tb3+ ions. The Ce3+ ion as a sensitizer could efficiently improve the performance of Tb3+ ion. First, with Ce3+ co-doping, the excitation spectrum of Tb3+ monitored at 541 nm showed a similar band that responds to the violet emission of Ce3+ monitored at 416 nm. Second, the quantum yields of Sr3Gd2(Si3O9)2:Tb3+ phosphors could be enhanced from 26.6% to 80.2% by co-doping Ce3+. Finally, the co-doping of Ce3+ was also effective to improve the thermal stability of Sr3Gd2(Si3O9)2:Tb3+. As the temperature rose to 150 °C, the emission intensity of Tb3+ remained at about 83.6% of that measured at room temperature, which was better than the commercial YAG:Ce phosphor in terms of their thermal quenching properties. These results indicated that the as-prepared Sr3Gd2(Si3O9)2:Tb3+,Ce3+ samples could be used as green emission phosphors for possible applications in near ultraviolet based WLEDs.

Highly Stable Mixed‐Lanthanide Metal–Organic Frameworks for Self‐Referencing and Colorimetric Luminescent pH Sensing

AbstractA strategy utilizing mixed‐lanthanide metal–organic frameworks (MOFs) for self‐referencing and colorimetric luminescent pH sensing has been developed. The mixed‐lanthanide MOFs EuxTb1−xHdpda (x=0.097, 0.205, 0.303, H4dpda=4‐(3,5‐dicarboxyphenyl)pyridine‐2,6‐dicarboxylic acid) exhibit excellent stability in phosphate buffer solution with pH values varying from 3.90 to 7.50. Density functional theory (DFT) calculations indicate that the deprotonation of uncoordinated carboxyl groups in ligands results in the elevation of the triplet excited state (T1) energy level of H4dpda, thus increasing the energy transfer probability from the T1 to 5D4 level of Tb3+. As a result, the emission intensity of Tb3+ in EuxTb1−xHdpda increases gradually while that of Eu3+ is almost not changed with the pH varying from 3.90 to 7.50. The intensity ratios of Eu3+ to Tb3+ can be correlated to the pH value, suggesting they are promising self‐referencing luminescent pH sensors. Furthermore, the significant pH‐dependent emission color change enables them to act as a luminescent colorimetric pH sensor for in situ and real‐time pH imaging. Because the energy transfer between the ligand and lanthanide ion can be easily tuned by selecting an appropriate ligand to further optimize the pH response range and sensitivity, such a strategy opens a new perspective for the development of self‐referencing luminescent pH sensors.

Tunable luminescence and temperature sensing behavior of Tb3+/Eu3+ co-doped borate glasses

The luminescent borate glasses co-doped Tb3+/Eu3+ were successfully synthesized by conventional melting quenching technique. Under 378 nm UV-light excitation, the 542 nm emission intensity of Tb3+ weakened gradually and a shorter decay time was found with increasing the content of Eu3+ concentration, confirming the occurrence of Tb3+ to Eu3+ energy transfer. The luminescent color tunable from pure green to yellow and finally to orange was observed in the Tb3+/Eu3+ co-doped borate glasses. The fluorescence intensity ratio between the 542 nm of Tb3+: 5D4 → 7F5 transition and 702 nm of Eu3+: 5D0 → 7F4 transition in the luminescent glass was found to be highly temperature-dependent with a good sensitivity of 0.357 % K−1. Such Tb3+/Eu3+ co-doped borate glasses may present potential application in solid-state lighting and optical temperature sensors.

Investigations of spherical Cu NPs in sodium lauryl sulphate with Tb3+ ions dispersed in PVA films

Cu nanoparticles (NPs) have been prepared in SDS solution using 1064nm laser radiation at different fluence 37J/cm2, 64J/cm2 and 88J/cm2 and structurally characterized. The TEM measurements reveal the presence of nanoparticles of spherical shape with different size. The size of the nanoparticles and their concentration increases with the increase of fluence.The effect of these Cu nanoparticles on the emissive properties of Tb3+ ion in polymer films has been studied. It is found that emission intensity of Tb3+ first increases and then deceases both with concentration of Cu NPs as well as with sizes. The PL intensity of Tb3+ ions is minimum for Cu NPs prepared with highest fluence. It has been explained in term of local field effect. This was also verified by life time measurements. These thin PVA films of copper nanoparticles displayed a highly temperature-dependent electrical conductivity with sensitivity at least comparable to commercial materials which suggest the use of these copper NPs embedded PVA films as novel, low-cost sensor materials.

Au@NaYF4:Tb3+ core@shell nanostructures: Synthesis and construction of luminescence resonance energy transfer

Luminescence resonance energy transfer (LRET) system can be constructed using NaYF4:Tb3+ luminescence nanocrystals and gold nanoparticles (AuNPs) served as energy donor and acceptor, respectively. The AuNPs modified by cetyltrimethylammonium bromide (CTAB) were synthesized first and NaYF4:Tb3+ shells encapsulated Au cores via a hydrothermal method. The synthesized materials were well characterized by X-ray diffraction (XRD), Fourier-transform infrared spectra (FT-IR), Transmission electron microscopy (TEM), X-ray photoelectron spectrum (XPS), UV–vis absorption spectra (UV–vis) and photoluminescence (PL) measurement. The results indicate that the synthesized Au@NaYF4:Tb3+ core–shell nanoparticles have spherical morphology with a size of 80–90nm and the shell layers of NaYF4:Tb3+ nanocrystals have pure cubic structure. The luminescence properties of Au@NaYF4:Tb3+ core–shell nanoparticles are same as those of NaYF4:Tb3+ particles. The LRET process was realized using the core–shell nanoarchitectures due to the absorption spectrum of AuNPs matches well with the major emission peaks of Tb3+ ions. The LRET experiments have successfully verified the energy transfer between NaYF4:Tb3+ nanocrystals and AuNPs. Additionally, the emission intensities of Tb3+ ions and the content of AuNPs exhibited a fair linear correlation.