Frequency Upconversion Fluorescence Research Articles

Near-infrared xanthene fluorescence probe for frequency upconversion fluorescence detection of HSO3− in evaluation of drug-induced hepatotoxicity

Bisulfite (HSO3−) plays an important role in life activities. Abnormal content of HSO3− may cause cardiovascular, cancer and other diseases. Frequency upconverted luminescent (FUCL) probes are a class of anti-Stokes luminescent materials with long-wavelength excitation and short-wavelength emission properties, which offer advantages in a range of applications due to their higher sensitivity and photostability. In addition, FUCL imaging has the advantages of high tissue penetration depth and low photo-damage, thus, it is more suitable for fluorescence imaging. In this work, a FUCL probe based on an xanthene fluorophore was designed and synthesised to detect HSO3−. The Probe PT-1 could respond to HSO3− and had high selectivity and sensitivity. It also exhibited a quenched FUCL signal. The detection limit of FUCL concerning HSO3− was 43 nM (λex = 730 nm), which is half the detection limit achieved under traditional excitation (93 nM, λex = 643 nm). Cell fluorescence imaging showed that PT-1 could effectively target mitochondria and monitor endogenous/exogenous HSO3− in living cells. More importantly, PT-1 was successfully used to monitor the level of HSO3− in mice with drug-induced liver injury through FUCL imaging.

Optical Upconversion Properties Of Tm2O3 / Yb2O3 Doped Lead Tellurite Glasses

The melt-quench process was used to create the lead-tellurite glasses codoped with lanthanides as thulium and ytterbium. Thermal characterization carried by differential scanning calorimetry. X-ray diffraction is studies to get the nature of sold sample. The UV-Visible-IR absorption spectra was carried in range of 300 nm to 1100 nm. There were four unique absorption peaks on the glass thulium –ytterbium doped glass. The frequency up-conversion (UC) fluorescence has been seen at room temperature by 975 nm excitation.

Temperature sensitivity based on Er3+ fluorescence fluctuation in Gd2Ti2O7: Er3+-Yb3+ porous nanofibers

Abstract (Gd1−x−yErxYby)2Ti2O7 (GTOEY) fibers were synthesized by electrospinning technique and heat-treatment processes, in which nano-scale fibers vested with homogeneous porous morphology, high crystallinity and elevated temperature heat-resistance. Under 977 nm laser excitation, GTOEY nanofibers exhibit effective frequency upconversion (UC) fluorescence, therefore, the violent green and dimmed red UC emissions are identified as two-photon absorption processes, attributing to 2H11/2/4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 radiation transitions of Er3+, respectively. Moreover, the temperature sensitivity based on UC emission fluctuation of Er3+ over a wide temperature range of 303–633 K has been derived. Thereby, having used a 980 nm laser and achieved green UC luminescence of GTOEY fibers centered at 525 and 545 nm, the maximum absolute and relative sensitivity values are obtained to be 0.382% K−1 and 1.12% K−1, respectively. These significant results demonstrate that the GTOEY nanofibers with distinct porous structure and admirable photothermal sensitivities can be regarded as a promising temperature sensing material used for overheating alarm and safety protection equipment.

Synthesis, electronic structure, linear and nonlinear photophysical properties of novel asymmetric branched compounds

A series of novel asymmetric branched compounds that utilize a 1,3,5-triazine core and feature D-π-A-(π-D′-π-A′)0-2 configurations (D = donor, A = acceptor, π = conjugated bridge) were designed, successfully synthesized, and fully characterized by 1H NMR, 13C NMR, FT-IR, and HRMS. Their photophysical properties including linear absorption, one-photon excited fluorescence, two-photon absorption, and frequency up-converted fluorescence, were systematically investigated in different solvents. With a rise in the polarity of solvents, the peak positions of the one-photon excited fluorescence are red-shifted and the Stokes shifts increase, while the linear absorption wavelengths change slightly. In addition, the target compounds except CZ show the positive solvatokinetic effect. With a rise in the number of branches, the red shifts of the absorption and emission maxima, the hyperchromicity of the molar absorption coefficients, and the decrease of the Stokes shifts are observed. The peripheral electron donors (carbazole, phenothiazine) and acceptors (pyridine, benzimidazole) also exert an important influence on the photophysical properties. Under excitation of 690–930 nm fs laser pulses, all the target compounds emit frequency up-converted fluorescence with the maximal peaks at 471–575 nm, and the two-photon absorption cross-sections in THF are 132 (PTZ), 182 (CZ), 453 (CZ-Py1), 844 (CZ-Py2), 1244 (CZ-BI1), and 2072 (CZ-BI2) GM, respectively. Their two-photon response is found to be nearly additive with respect to the number of branches. The time-dependent density functional theory calculations were conducted to gain an insight into their electronic structures and to better understand the structure-photophysical property relationships. The results clearly indicate the importance of appropriate structural units on the enhancement of two-photon absorption properties.

Linear and V-shaped carbazole-based molecules functionalized by cyano acceptors and diversified donors: Synthesis, single- and two-photon related photophysical properties

A series of novel linear and V-shaped carbazole-based molecules functionalized by cyano acceptors and diversified donors (carbazole, diphenylamino, dimethylamino, methoxy, and ferrocene) were synthesized and characterized by hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, Fourier transform infrared spectroscopy, and high-resolution mass spectrometry. Their linear and nonlinear optical properties including UV–visible absorption, single-photon excited fluorescence, two-photon absorption, and frequency up-converted fluorescence, were systematically investigated in various solvents. The time-resolved photoluminescence studies using time-correlated single photon counting revealed their fluorescence lifetimes in THF. The solvent polarity exerts little effect on their absorption properties, while the emission properties (maximum fluorescence wavelength, Stokes shift, fluorescence quantum yield) display solvent polarity dependencies. Donor-acceptor functionalities and molecular dimensionality are considered to be the crucial structural factors that influence their optical properties. Pumped by a femtosecond laser (690–990 nm, 80 MHz, 140 fs), all the target molecules emit intense frequency up-converted fluorescence except FC1 and FC2 which contain one or two ferrocene donors. The two-photon absorption cross-sections in THF are in the range of 631–3014 GM. The density functional theory calculations were also conducted to unravel their electronic structures and to further understand the structure-property relationships. To our knowledge, this study is the first to be concerned with the single- and two-photon related photophysical properties of these D-π-A-π-D′ and D′-π-A-π-D-π-A-π-D′ carbazole-based molecules (D = donor, A = acceptor, π = conjugated bridge).

铝锗酸盐玻璃中铒离子升频荧光光子定量

铝锗酸盐玻璃中铒离子升频荧光光子定量

Investigation of photophysical properties of new branched compounds with triazine and benzimidazole units

Three new acceptor–donor–acceptor branched compounds with triazine and benzimidazole units (M1, M2, and M3) were synthesized and characterized by infrared, hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, mass spectrometry, and elemental analysis. Their photophysical properties were investigated including linear absorption, single-photon excited fluorescence, fluorescence quantum yield, two-photon absorption, and frequency up-converted fluorescence. When the number of branches increases, the spectral positions of the linear absorption and the single-photon excited fluorescence show red shifts, while the fluorescence quantum yields decrease. When the polarity of solvents increases, the spectral positions of the single-photon excited fluorescence and the Stokes shifts also show red shifts, while the fluorescence quantum yields of the two-branched compound (M2) and three-branched compound (M3) decrease. Under the excitation of an 800 nm laser with a pulse width of 80 fs, all these compounds emit intense green frequency up-converted fluorescence, and the two-photon absorption cross-sections are 210, 968, and 1613 GM for M1, M2, and M3, respectively. This result shows that significant enhancement of the two-photon absorption cross-section can be achieved by sufficient electronic coupling between the strong charge transfer acceptor–donor–acceptor quadrupolar branches through the s-triazine core.

Synthesis and photophysical properties of new s-triazine derivatives containing A–π–D–π–A quadrupolar branches

Four new s-triazine derivatives containing one or two acceptor–π-donor–π-acceptor quadrupolar branches (S1, E1, S2, E2) were synthesized and characterized by infrared, hydrogen nuclear magnetic resonance, mass spectrometry and elemental analysis. Their photophysical properties were investigated including linear absorption, single-photon excited fluorescence, fluorescence quantum yield, two-photon absorption, and frequency up-converted fluorescence. The spectral positions of the linear absorption and the single-photon excited fluorescence show red-shifts with enhanced electron-accepting ability of the end-group or increasing number of branch. The fluorescence quantum yields of the two-branched compounds (S2, E2) decrease with increasing solvent polarity. Under the excitation of a 800 nm laser with a pulse width of 80 fs, all these compounds emit intense green frequency up-converted fluorescence, and the two-photon absorption cross-sections are 80, 48, 502, and 362 GM for S1, E1, S2, and E2, respectively. This result shows that significant enhancement of the two-photon absorption cross-section can be achieved by sufficient electronic coupling between the strong charge transfer quadrupolar branches through the s-triazine center.

Synthesis, two‐photon absorption, and optical power limiting of new linear and hyperbranched conjugated polyynes based on bithiazole and triphenylamine

AbstractTwo new linear and hyperbranched conjugated polymers P1 and P2 have been synthesized by Sonogashira coupling reaction, in which the main chain consists of bithiazole moieties as electron acceptors and triphenylamino groups as donors. The conjugated polymers were characterized by TGA, UV–vis absorption, fluorescence emission, electrochemical cyclic voltammetry, and two‐photon absorption measurements. They exhibited excellent solubility in organic solvents and high thermal stability (5% of weight loss at 299 °C). The two‐photon absorption cross sections (σ) measured by the open aperture Z‐scan technique using 140 femtosecond (fs) pulse were determined to be 1014 and 552 GM per repeating unit for P1 and P2, respectively. This result shows that the σ of linear conjugated P1 is higher than that of hyperbranched P2, indicating that the linear polymer offers better intramolecular charge transfer ability. In THF, P1 and P2 exhibit intense frequency up‐converted fluorescence under the excitation of 140 fs pulses at 800 nm with the peaks located at 580 and 548 nm, respectively. Meanwhile, the optical limiting behaviors for the polymers were studied by using a focused 800 nm laser beam of 140 fs duration. It was found that these polymers also exhibit good optical‐limiting properties and make them potential candidates for optical limiters in the photonic fields. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Up-conversion sensitization luminescence in Pr3+and Yb3+ co-doped fluoride glasses

In experiment, Pr3+,Yb3+:ZBLAN glass is chosen as a frequency up-conversion fluorescence material, and detailed reasons for choosing ZBLAN glass as a material are given. In this paper we also analyze the relations between up-conversion fluorescence intensity and pump light intensity and between up-conversion fluorescence intensity and ions doped concentration. Therefore we obtain experimental conditions to realize a clear two-frequency up-conversion 3-D display.

Efficient two-photon sensitized luminescence of europium (III) complex based on hypersensitive transitions

Red frequency-upconversion fluorescence emission is observed in europium (III) complex with encapsulating polybenzimidazole tripodal ligands, pumped with 930- and 1070-nm picosecond laser pulses. The luminescence of transition 5D0->7F2 (612 nm) is induced by two-photon absorption of hypersensitive transitions 7F0->5D2 (465 nm) and 7F1->5D1 (535 nm). Analysis results suggest that the two-photon excitation strength of these hypersensitive transitions is increased dramatically owing to the C3 symmetry of the coordination field.

Synthesis and two‐photon absorption properties of hyperbranched diketo‐pyrrolo‐pyrrole polymer with triphenylamine as the core

AbstractA novel hyperbranched polyyne (hb‐DPP) with triphenylamine as the core, 2,5‐dioctylpyrrolo [3,4‐c]pyrrole‐1,4 (2H,5H)‐dione (DPP) as the connecting unit has been designed and synthesized by Glaser‐Hay oxidative coupling reaction, which was characterized by IR, NMR, UV‐vis, FL, and GPC. The polymer exhibits high molecular weight (Mw up to ∼6.55 × 104 Da) and is readily soluble in common organic solvents such as toluene, chloroform, tetrahydrofuran, N,N‐dimethyl formamide and so on. The one‐ and two‐photon absorption (TPA) properties have been investigated. The TPA cross section of the polymer was measured by open‐aperture Z‐scan experiment using 140 femtosecond (fs) pulse, and the TPA cross section for hb‐DPP was determined to be 579 GM per repeating unit at wavelength of 800 nm. In tetrahydrofuran, hb‐DPP exhibits intense frequency up‐converted fluorescence with the peak located at 584 nm under the excitation of 800 nm fs pulses. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4400–4408, 2009

Improvement on the up-conversion fluorescence emission in Tm3+ doped optical materials by adjusting phonon distribution

The influence of phonon distribution on the frequency upconverted fluorescence emission is studied with laser spectroscopy in different matrices and at different ambient temperatures. The spectrum of phonon energy can be adjusted by varying the content of SiO2 in the oxyfluoride glass and glass ceramics, which affects the upconverted fluorescence emission of doped ions. Since the phonon energy depends on the sample temperature, the variation of the temperature can also influence the population rate of 3H4 level in Tm3+ doped low-phonon-energy LaF3 crystal, resulting in a change of the fluorescence upconversion.

Study on the three-photon properties of a triphenylamine derivative with three conjugated branches

Three-photon pumped frequency-upconversion fluorescence and nonlinear transmission properties of tris-[4-(2-{4-[5-(4-tert-butyl-phenyl)-[1,3,4]oxadiazol-2-yl]-phenyl}-vinyl)-phenyl]-amine (TPAD3) are studied using a Ti:Sapphire oscillator–amplifier system associated with an optical-parametric amplifier, which could specifically provide ∼80 fs duration and 1175–1300 nm laser pulses for three-photon excitation. The dye shows very efficient three-photon pumped frequency-upconversion fluorescence and three-photon absorption at wavelengths from 1175 nm to 1300 nm. In our study, the beam intensity distribution is also taken into account. For the first time we give the analytical solution to nonlinear transmission of a three-photon absorption process when the incident beam has a Gaussian transverse spatial profile.

Three-Photon Absorption and Upconversion Fluorescence Properties of Series 1,3,4-Oxadiazole Derivatives

A newly synthesized 1,3,4-oxadiazole derivatives have been studied using a femtosecond Ti:sapphire laser system. The series molecules present strong three-photon absorption and frequency upconversion fluorescence at wavelengths from 1205nm to 1575nm. Furthermore, there is no proportional relationship between three-photon absorption cross sections and the chemical structure transformation from monomer, dimer to trimer. Effective charge-transfer distance by π-conjugation bonds may be the contributing factor. In the experimental design, the far-field intensity distribution of femtosecond laser beam has been taken into account. We give the optimized analytical solution of nonlinear transmission in a three-photon absorption (3PA) process when the incident beam has a Gaussian transverse spatial profile.

Two-Photon Frequency-Upconversion Fluorescence of Multibranch Chromophores with Nitrogen-Coupling Center

Two-photon absorption (TPA) properties of multibranch chromophores with nitrogen coupling center, N-[4-{2-(3,5-di-{5-[4-(tert-butyl)phenyl]-1,3,4-oxadiazol-2-yl}phenyl)-1-ethenyl}phenyl]-N,N-diphenylamine (BPODPA), N,N-bis[4-{2-(3,5-di-{5-[4-(tert-butyl)phenyl]-1,3,4-oxadiazol-2-yl}phenyl)-1-ethenyl}phenyl]-N-phenylamine (BBPOPA) and N,N,N-tris[4-{2-(3,5-di-{5-[4-(tert-butyl)phenyl]-1,3,4-oxadiazol-2-yl}phenyl)-1-ethenyl}phenyl] amine (TBPOA),were measured by nonlinear transmission method. Single photon excited fluorescence and two-photon excited fluorescence (TPEF) of the chromophores were studied. The effect of dendronization on the TPA and TPEF characters of triphenylamine-based chromophores was investigated. When pumped with 800 nm laser irradiation, chromophores BPODPA, BBPOPA, and TBPOA showed strong two-photon excited blue green fluorescence at 502, 515, and 518 nm, respectively. These multibranched chromophores showed large TPA cross-section. The enhanced two-photon absorption found in these chromophores was attributed to the fact that the multibranched chromophores had both an extended -conjugated system and an increased intramolecular cooperative effect compared to the one-branched chromophore.

Energy transfer between Tm3+ and Er3+ ions in a TeO2-based glass pumped at diode laser wavelength

In this paper we investigate the energy transfer processes in Tm3+/Er3+ doped telluride glass pumped at the commercial diode laser pump wavelength ∼800nm. Tailoring the rare-earths content in the glass matrix, seven main energy transfer channels within the doping range considered were identified. A 6-fold enhancement of the Er3+ visible frequency upconversion fluorescence at ∼660nm is observed due to the inclusion of Tm3+ ions. This is evidence of the relevant contribution of the route Er1(4I11/2)+Er2(4I13/2)→Er1(4I15/2)+Er2(4F9/2) to the process. Energy migration among pumped 4I9/2 level reducing the efficiency of the upconversion emission rate (3H11/2, 4S3/2, and 4F9/2) is observed for Er3+ above 1.5wt%. The rate equations regarding the observed energy transfer routes are determined and a qualitative analysis of the observed processes is reported.

Synthesis and Two-photon Properties of New Perylene Bisimide Derivatives

Abstract The synthesis of some novel perylene bisimide derivatives was reported and their linear absorption, emission, and two-photon properties were measured and discussed. Two-photon cross-sections for these compounds were determined to be 8735 GM maximum (nonlinear transmittance, ≈7 ns, 10 Hz and 850 nm). The frequency upconversion fluorescence was observed under the excitation of 850-nm-nanoseconds laser pulses with the peaks located around 669 nm.

Energy transfer processes on both Er 3+ ion concentration and excitation densities in Yb 3+–Er 3+ codoped LaF 3 matrix

The effects of both Er 3+ ion concentration and excited density upon frequency upconversion fluorescence emissions in Er 3+/Yb 3+-codoped LaF 3 powder are investigated. The results reveal that a higher Er 3+ concentration can induce not only upconversion emission enhancements but also the changes among the relative intensities of the 407, 519, 539 and 651 nm radiation transitions as the samples are excited within the ranges of 20 to 700 mW with 978 nm laser diode (LD) as an excitation source. The changes are described by a schematic level model with the cross-relaxation processes between Er 3+ ions and a series of dynamic equations that take into account the population of temperature dependent in Er 3+.

Blue upconversion luminescence generation in Ce3+:Gd2SiO5 crystals by infrared femtosecond laser irradiation

Blue frequency-upconversion fluorescence emission has been observed in Ce(3+)-doped Gd(2)SiO(5) single crystals, pumped with 120-fs 800 nm IR laser pulses. The observed fluorescence emission peaks at about 440nm is due to 5d?4f transition of Ce3+ ions. The intensity dependence of the blue fluorescence emission on the IR excitation laser power obeys the cubic law, demonstrating three-photon absorption process. Analysis suggested that three-photon simultaneous absorption induced population inversion should be the predominant frequency upconversion mechanism.