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A set of W/Cu/S cluster-supported supramolecular wire and rectangle compounds were assembled and exhibited enhanced third-order nonlinear optical responses.

Designing and building unique cage assemblies attract increasing interest from supramolecular chemists but remain synthetically challenging. Herein, we propose the use of a flexible vertex with adjustable angles to selectively form highly distorted tetrahedral and octahedral cages, for the first time, in which the flexible vertex forms from the synergistic effect of coordination and covalent interactions. The inherent interligand angle of the vertex can be modulated by guest anions present, which allows for the fine-tuning of different cage geometries. Furthermore, the reversible structural transformation between tetrahedral and octahedral cages was achieved by anion exchange monitored by mass spectrometric technique, the smaller anions favoring tetrahedral cages, while the larger anions supporting octahedral cages. Additionally, the KBr-based cage thin films exhibited prominent enhancement of their third-order NLO responses in two or three orders of magnitude compared to those obtained for their corresponding solutions. This work not only provides a new methodology to build irregular polyhedral structures in a controlled and tunable way but also provides access to new kinds of promising functional optical materials.

All-inorganic lead halide perovskites have gained considerable interest owing to their potential applications in an array of high-performance optoelectronic devices. However, producing highly luminescent, nearly pinhole-free, all-inorganic perovskite films through a simple solution process remains challenging. Here, we provide a detailed investigation of the crystallization control of inorganic perovskite films fabricated by a one-step spin-coating process. Our results reveal that the coating temperature in the fabrication process is of paramount importance in influencing perovskite crystallization and that lowering the coating temperature and fine stoichiometry modification of the precursors favor the suppression of trap states in CsPbBr3 perovskite films. A broad range of experimental characterizations help us identify that nonsynergistic assembly of solutes, resulting from poor diffusion capability of inorganic salts, is the dominant cause for the inhomogeneous element distribution, low luminescence yi...

Five stable clusters sharing the cuboidal [Ni4O4] skeleton are subjected to third-order nonlinear optical (NLO) property measurements. Preliminary results suggest that the NLO property is largely defined by the cluster core skeleton and the directly coordinated atoms, with limited contribution from the heavy atoms peripherally attached to the aromatic ligands.

The optical limiting properties of CuPcTs, NiPcTs and CoPcTs were investigated with nanosecond pulses at the wavelength of 532nm. Among them, CuPcTs exhibits the strongest optical limiting effect. An explanation based on nonlinear absorption and refraction is provided. And also, the relationship between the d-electron configuration and the third-order nonlinear optical properties of CuPcTs, NiPcTs and CoPcTs were discussed.

Rare earth ion-doped Y2O3nanoparticles are attractive for biological imaging applications due to their non-toxicity, resistance to photobleaching, and possibility for upconversion. Y2O3:Yb3+/Tm3+nanocrystals display photoluminescence (PL) with a peak at ~811nm if excited at ~980nm. This Near-Infrared to Near-Infrared (NIR-to-NIR) upconversion (UC) process provides deeper light penetration into biological specimen and results in high contrast optical imaging due to absence of an autofluorescence background and decreased light scattering. Here, we report that NIR-to-NIR UC PL intensity of Y2O3:Yb3+/Tm3+nanocrystals are enhanced by doping with different Tm3+ions and Li+ions concentration. When the Tm3+ions concentration reaches 0.25 mol%, the NIR-to-NIR UC PL intensity is the strongest. And the NIR-to-NIR UC PL intensity of Y2O3:5 mol % Yb3+ions, 0.25mol% Tm3+ions and 5mol% Li+ions is maximum, which is more that about 14 times than that of no doped Li+ions. This material may show promise for use as probes for biological imaging.

Two Ag(I)-bridged metal-organic polymers: 2D double-crossed layer polymer {[Ag(bpfp)] · NO3 · H2O)}n (bpfp = N,N′-bis(3-pyridylformyl)-piperazine) (1) and 1D zigzag chain polymer {[Ag(btx)] · NO3}n (btx = 1,4-bis(triazol-1-ylmethyl)-benzene) (2) have been prepared and structurally characterized by single crystal diffraction. Their third-order nonlinear optical (NLO) properties and optical limiting (OL) effects were determined by Z-scan technique. The results show that both polymers possess strong optical nonlinear absorption and optical nonlinear refraction, and exhibit strong OL effect to nanosecond and picosecond incident pulsed laser. By comparing the optical nonlinearities of the polymers and purely bpfp and btx ligands, we find that the incorporation of Ag ion can largely enhance the optical nonlinearities of organic molecules attached. DFT calculation further confirms the corporate contributions of Ag ions and bridge ligands to the optical nonlinearities.

The combination of metal ions with H3tbba has resulted in the formation of two three dimensional coordination compounds {[Zn(H2tbba)2(H2O)] · 2(OC3H6)} n (1) and {[Mn(H2tbba)2(H2O)] · 2(OC3H6)} n (2) (H2tbba = 2-thiobarbituric acid anion). Compounds 1 and 2 are isostructural with metal ions bridged by four hydroxyl oxygens from four different H2tbba ligands to form a 3D network. H2tbba exhibits bidentate coordination with both hydroxyl oxygens participating in coordination, a new coordination mode. Nonlinear absorption and refraction of 1 and 2 in DMF are studied by using Z-scan measurement technique at 532 nm. 1 and 2 possess nonlinear optical absorption and self-focusing.

Cation-templated self-assembly of 1,ω-bis(pyridinium)alkanes (ω = 1−6) with cuprous thiocyanate was studied, and six sparse polymeric thiocyanate frameworks were obtained and characterized by X-ray crystallography: {(bpm)[Cu(NCS)4]}n (1), {(bpe)[Cu2(NCS)4]}n (2), {(bppp)[Cu(NCS)3]}n (3), {(bpbt)[Cu(NCS)4]}n (4), {(bppt)[Cu2(NCS)4]}n (5), and {(bph) [Cu2(NCS)4]}n (6) (bpm = 1,1′-bis(pyridinium)methylene, bpe = 1,2-bis(pyridinium)ethane, bppp = 1,3-bis(pyridinium)propane, bpbt = 1,4-bis(pyridinium)butane, bppt = 1,5-bis(pyridinium)pentane, bph = 1,6-bis(pyridinium) hexane). The structures consist of 0−3-dimensional frameworks with the bispyridinium cations trapped within host network cavities. Compound 1 has a 3D porous (6,3)/(6,4) joint topology structure, compounds 2 and 5 have two-dimensional polypseudorotaxane interlocked structures, compound 3 has a dimeric structure, compound 4 has a two-dimensional honeycomb structure, and compound 6 exhibits an interesting 1D hanging ladder-shaped complementary chai...

Reaction of a cluster precursor [Et4N]2[MoOS3(CuCN)] (1) with equimolar [Cu(MeCN)4](PF6) in MeCN/aniline gave rise to an interesting polymeric cluster {[Et4N]2[MoOS3Cu2(μ-CN)]2·2aniline}n (2), whil...

A series of bromo-terminated four-armed homopolymers [polystyrene (PSt) and poly(methyl methacrylate) (PMMA)], prepared by atom transfer radical polymerization (ATRP), were subsequently functionalized with fullerene C60 by atom transfer radical addition (ATRA) reaction using CuBr/2,2′-bipyridine (bipy) as the catalyst system. The C60 end-capped four-armed polymer derivatives were then characterized by gel permeation chromatography (GPC), UV–vis, FT-IR, thermal gravimetric analyses (TGA) and differential scanning calorimeter (DSC). Another technique of synthesizing C60-functionalized four-armed polymers from azide functional polymers was also applied for comparison. The optical limiting behavior of C60 end-capped four-armed polymers prepared via ATRA reaction were measured in THF solution at 532 nm. Both groups of fullerene-functionalized polymers (C60-PSts and C60-PMMAs) are provided with optical limiting properties.

Reaction of trans-[(η5-C5Me5)2Mo2(μ-S)2S2] (1) with 2 equiv of CuI in CH2Cl2 at ambient temperature or in refluxing MeCN afforded two isomeric clusters, [(η5-C5Me5)2Mo2(μ3-S)3S(CuI)2] (2) and [(η5-...

The third-order nonlinear refractive response in a kind of thin phthalocyanine film has been investigated using two types of top-hat Z-scan techniques with a picoseconds pulses laser at wavelength of 532nm. The nonlinear phase shift of this sample is so week because of the very small thickness of the films, and the normal top-hat Z-scan technique is often difficult to measure the results. To research the nonlinear response of this thin film, we also has been measured it using the modified top-hat Z-scan technique under the experimental conditions of the same. The curve of the modified top-hat Z-scan for the nonlinear refraction is only a single peak and the result shows this kind of film has obvious response of nonlinear refraction with 19 picoseconds pulses. Furthermore, we have been carried on the theoretical analysis and the numerical simulation with the result of the experiment, and the theoretical simulation fit well with experimental results, the value of the nonlinear refraction index is obtained to be n 2 = 6.25×10 −15 m 2 / W . By comparing the measured curve of the two, the results indicate that the sensitivity of the modified top-hat Z-scan measurement is greatly enhanced.

The zero-dimensional polymer [Pb 6 (μ 2 OOCCH=CHFc) 2 -(μ 3 -OOCCH=CHFc) 2 (μ 2 -η 2 -OOCCH=CHFc) 2 (η 2 -OOCCH= CHFc) 2 (μ 4 -O) 2 ] (1), the one-dimensional chain polymers [Pb(η 1 -μ 2 -OOCCH=CHFc) 2 (Phen)] n (phen = phenanthroline; (2), j[Cd(μ 2 -η 2 -OOCCH=GHFc)(η 2 -OOCCH=CHFc)(H 2 O) 2 ]-(H 2 O) 4 ] n (3), and the two-dimensional hybrid polymer {[Cd-(η 2 -OOCCH=CHFC)(bbbm) 1 . 5 Cl].1.5H 2 O} n [bbbm = 1,1'-(1,4-butanediyl)bis-1H-benzimidazole; 4] have been prepared by the reaction of sodium β-ferrocenylacrylate [FcCH= CHCOONa, Fc = (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )] with the appropriate metal salts. Solution-state differential pulse voltammetry for 1-4 indicated that the half-wave potentials of the ferrocenyl moieties in these polymers are all shifted to positive potential compared with that of sodium β-ferrocenylacrylate. The four polymers' third-order nonlinear optical (NLO) properties were determined by the Z-scan technique in DMF solutions. The results show that these polymers possess good nonlinear optical refraction effects. Their hyperpolarizability (y) values are calculated to be 4.80 × 10 - 3 0 , 5.19 × 10 - 3 0 , 1.57 × 10 - 2 9 , and 2.04 × 10 - 2 9 esu for 1-4, respectively. The γ values of the Cd I I polymers (3 and 4) are slightly larger than those of the Pb I I polymers (1 and 2), which indicates that the metal ions play an important role in the NLO properties of these polymers.

We demonstrate an all-optical strategy for realizing spherical three-dimensional (3D) super-resolution (∼λ3/22) spot arrays of pure longitudinal magnetization by exploiting a 4π optical microscopic setup with two high numerical aperture (NA) objective lenses, which focus and interfere two modulated vectorial beams. Multiple phase filters (MPFs) are designed via an analytical approach derived from the vectorial Debye diffraction theory to modulate the two circularly polarized beams. The system is tailored to constructively interfere the longitudinal magnetization components, while simultaneously destructively interfering the azimuthal ones. As a result, the magnetization field is not only purely longitudinal but also super-resolved in all three dimensions. Furthermore, the MPFs can be designed analytically to control the number and locations of the super-resolved magnetization spots to produce both uniform and nonuniform arrays in a 3D volume. Thus, an all-optical control of all the properties of light-induced magnetization spot arrays has been demonstrated for the first time. These results open up broad applications in magnetic-optical devices such as confocal and multifocal magnetic resonance microscopy, 3D ultrahigh-density magneto-optic memory, and light-induced magneto-lithography. A scheme for making 3D arrays of subwavelength magnetization spots will benefit the high-density data storage and magnetic resonance microscopy. Zhong-Quan Nie and co-workers used two high-numerical-aperture lenses to focus and interfere a pair of circularly polarized Bessel Gaussian beams. They used spatial light modulators to modulate the wavefronts of the two beams in such a way that enhanced longitudinal magnetization components through constructive interference and simultaneously cancelled the azimuthal components by deconstructive interference. This generated an array of super-resolution spots of pure longitudinal magnetization. The number and location of the spots can be varied by changing the signal sent to the spatial light modulator. This is the first demonstration of all-optical control of all the properties of light-induced magnetization spot arrays and is promising for developing the light-induced magnetic data storage and lithography devices.

Lanthanide doped oxides nano materials have novel optical, physical and structural properties. Cubic Ho 3+ -Yb 3+ -Tm 3+ co-doped Gd 2 O 3 nanotubes are synthetize by a simple wet-chemical route at low temperature and ambient pressure followed by subsequent annealing heat treatment in muffle furnace. Nanotubes are formed by adjusting the pH value of reacting solution. The introduction of Yb 3+ leads to strong visible upconversion luminescence and change the intensity ratio of the green, blue and red luminescence. In trichromatic laser display, research of how to enhance blue light is in the bottleneck period. In the experiment, the blue emission has been successfully improved. In certain doping ratio, distinct enhancement of blue emission and obvious degradation of green light have been observed, which is discussed in detail. X-Ray powder diffraction (XRD), scanning electron microscope (SEM) and upconversion (UC) emission spectra are used to characterize the sample. Strong and adjusted upconversion luminescence determine that the nano material is a potential candidate for applications of biological probe, color displays, lighting and photonics.

In this report, we mainly focus on the dynamic of the transient thermal effect of the C70/toluene at nanosecond time-domain. We use the time-resolved pump-probe system based on 4f coherent imaging system with phase object with nanosecond laser pulse at the wavelength of 532nm.By changing the delay time, we can get different linear and nonlinear image. So the dynamic process of the transient thermal can be studied. In the experiment, we choose 5ns, 8ns and 10ns, and found the nonlinear refractive index arises by the delay time.

The Gd 2 O 3 hollow microspheres have been successfully fabricated via carbonaceous polysaccharide microspheres as templates and urea as a precipitating agent, which involved the deposition of an inorganic coating on the surface of carbon microsphere, followed by heat treated 800°C for 4h. The obtained high uniform Gd 2 O 3 microspheres with a spherical shape and hollow structure are uniform in size and distribution. The possible mechanism of evolution from glucose to carbonaceous polysaccharide microspheres and the chemical reaction of each step to form the final hollow spheres are proposed. The rare earth ion Ln 3+ doped Gd 2 O 3 (Ln = Er, Yb and Tm) hollow microspheres show bright up-conversion luminescence with different colors coming from different activator ions under ultraviolet or 980 nm light excitation, which may open new possibilities to synthesize other hollow spherical materials and extend their applications.

In the present letter, the transparent oxyfluoride glass ceramics containing Ho 3+ -Tm 3+ -Yb 3+ :NaYF 4 were successfully prepared by melt-quenching at 1400°C and subsequent heating at 650-680°C for 1~2 hours . X-ray diffraction (XRD) with Cu K α radiation (λ=0.154nm) investigation revealed that NaYF 4 nano-crystals in the glass ceramics was fabricated. Their sizes were determined by Sherrer's equation. The emission spectra red green and blue up-conversion (UC) under 980nm laser diode (LD) pumping and absorption spectra were measured. Luminescence measurements confirmed the partition of RE ions in nano-crystals NaYF 4 . The blue red and green UC radiations correspond to the transitions 1 G 4 - 3 H 6 , 1 G 4 - 3 H 4 of Tm 3+ , 5 F 4 , 5 S 2 - 5 I 8 , 5 F 5 - 5 I 8 , of Ho 3+ ions, respectively. This is similar to that in Tm 3+ -Yb 3+ and/or Ho 3+ -Yb 3+ co-doped glass ceramics. To obtain upconversion fluorescence mechanisms, upconversion fluorescence intensity versus LD pump power were analyzed in view of energy levels of rare earth. Up-conversion mechanisms were discussed and the ratio between red, green and blue UC emission bands was found to be varied as a function of temperature of heat treatment and pump power. This result could be mainly attributed to the cross-relaxation between Ho 3+ ions. The excellent optical properties and its convenient, low-cost synthesis of the present glass ceramic imply that it is an excellent substitution material for the unobtainable bulk NaYF 4 crystal and may have potentially applications in tunable visible laser or many other fields.

The third-order optical nonlinearities of semiconductor CdS are investigated using 4f nonlinear image technique with phase object at 745 nm. The measurement method is based on the 4f coherent optical processor system in Fourier optics. The nonlinear parameters of sample can be verified by numerical fitting the nonlinear image at the output plane of 4f system which obtained by a CCD camera. Using one-single-shot, the two-photon absorption coefficient β and nonlinear refraction index n2 of the CdS which arranged at the Fourier plane are determined simultaneously. The experimental results shows CdS has reverse saturable absorption and self-defocusing effect at 745 nm, indicating this material is a good candidate for future photonics applications.

A nonlinear image technique for characterization of the optical nonlinearities is used to investigate the solid semiconductor ZnSe at 600 nm. The method based on a 4f nonlinear image technique with a phase object is used to obtain the diffraction pattern of the nonlinear filter in solid ZnSe located at the Fourier plane by a CCD camera. The nonlinear absorption coefficient and nonlinear refraction index were both obtained by fitting the nonlinear image. Good agreement between the experiment data and the simulated result are obtained indicating a sensitive and powerful method for nonlinear optical measurements.

The construction of a new set of [(eta5-C5Me5)MoS3Cu3]-based supramolecular compounds with different one-dimensional (1D) arrays from two preformed clusters [PPh4][(eta5-C5Me5)MoS3(CuX)3] (X = Br (1a), NCS (1b)) with 1,2-bis(4-pyridyl)ethane (bpe) and 1,3-bis(4-pyridyl)propane (bpp) is presented. Reactions of 1a with bpe in different molar ratios afforded ([((eta5-C5Me5)MoS3Cu3) 2(mu-bpe)3.5Br4].MeCN) n (2), ([((eta5-C5Me5)MoS3Cu3)2(mu-bpe)3Br4].Sol)n (3a: Sol = DMSO.3MeCN; 3b: Sol = 2aniline.3MeCN), ([((eta5-C 5Me5)MoS3Cu3)2(mu-bpe)3(bpe)Br4].0.35DMF)n (4), and ([((eta5-C5Me5)MoS3Cu3)2(mu-bpe)2(mu-Br)(mu3-Br)Br2].DMF.MeCN)n (5). On the other hand, treatment of 1a or 1b with bpp produced [(eta5-C5Me5)MoS3Cu3(mu-bpp)(mu-Br)Br]n (6) and ([((eta5-C5Me5)MoS3Cu3)2(mu-bpp)3(mu-NCS)2(NCS)](NCS))n (7). Compounds 2-7 have been characterized by elemental analysis, UV-vis spectroscopy, IR spectroscopy, 1H NMR, and X-ray analysis. In 2, each [(eta5-C5Me5)MoS3Cu3] core serves as an angular two-connecting node to link other equivalent cores by single and double bpe bridges to form a 1D "Great Wall"-like chain. In 3a and 3b, the [(eta5-C5Me5)MoS3Cu3] cores are linked alternatively by single and double bpe bridges to give a 1D zigzag chain. In 4, six cluster cores (two as a two-connecting node and four as a three-connecting node) are connected by four single bpe and two double bpe bridges to form a cyclohexane-shaped repeating unit, which is further fused with other units to generate a 1D double-stranded chain. Compound 5 has a simple 1D zigzag chain consisting of the cluster cores linked by single bpe bridges. In 6, the cluster cores are linked by single bpp bridges to give a 1D helical chain, which further holds two symmetry-related chains through C-H...Br hydrogen-bonding interactions, thereby forming a 1D H-bonded triple-stranded chain. Compound 7 has a rare 1D quadruple chain, in which the [(eta5-C5Me5)MoS3Cu3] cores work as planar four- and five-connecting nodes to interconnect other equivalent cores through single bpp bridges and single and double thiocyanate bridges. In addition, the third-order nonlinear optical properties of 1a, 2, 3a, and 4-7 in aniline were also investigated by using the Z-scan technique with a 4.5 ns pulse laser at 532 nm.

The assembly of a new family of [(eta5-C5Me5)MoS3Cu3]-supported supramolecular compounds from a preformed cluster [PPh4][(eta5-C5Me5)MoS3(CuNCS)3].DMF (1.DMF) with four multitopic ligands with different symmetries is described. Reactions of 1 with 1,2-bis(4-pyridyl)ethane (bpe) (Cs symmetry) or 1,4-pyrazine (1,4-pyz) (D2h symmetry) in aniline gave rise to two polymeric clusters {[{(eta5-C5Me5)MoS3Cu3}2(NCS)3(mu-NCS)(bpe)3].3aniline}n (2) and [(eta5-C5Me5)MoS3Cu3(1,4-pyz)(mu-NCS)2]n (3). On the other hand, solid-state reactions of 1 with 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) (D3h symmetry) or 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (H2tpyp) (D4h symmetry if 21H and 23H of the H2tpyp are omitted) at 100 degrees C for 12 h followed by extraction with aniline yielded another two polymeric clusters {[(eta5-C5Me5)MoS3Cu3(tpt)(aniline)(NCS)2].0.75aniline. 0.5H2O}n (4) and {[(eta5-C5Me5)MoS3Cu3(NCS)(mu-NCS)(H2tpyp)0.4(Cu-tpyp)0.1].2aniline.2.5benzene}n (5). These compounds were characterized by elemental analysis, IR spectra, UV-vis spectra, 1H NMR, and X-ray analysis. Compound 2 consists of a 2D (6,3) network in which [(eta5-C5Me5)MoS3Cu3] cores serve both a T-shaped three-connecting node and an angular two-connecting node to interconnect other equivalent units through single bpe bridges, double bpe bridges, and mu-NCS bridges. Compound 3 has a 3D diamondlike framework in which each [(eta5-C5Me5)MoS3Cu3] core, acting as a tetrahedral connecting node, links four other neighboring units by 1,4-pyz bridges and mu-NCS bridges. Compound 4 contains a honeycomb 2D (6,3)core(6,3)tpt network in which each cluster core, serving a trigonal-planar three-connecting node, links three pairs of equivalent cluster cores via three tpt lignads. Compound 5 has a rare scalelike 2D (4,62)core(42,62)ligand network in which each cluster core acts as a T-shaped three-connecting node to link with other equivalent ones through mu-NCS bridges and H2tpyp (or Cu-tpyp) ligands. The results showed that the formation of the four different multidimensional topological structures was evidently affected by the symmetry of the ligands used. In addition, the third-order nonlinear optical properties of 1-5 in aniline were also investigated by using Z-scan techniques at 532 nm.

A novel 3D porous coordination complex based on a twin-nest-shaped heterothiometallic cluster has been synthesized and characterized. The complex shows an unprecedented structure type and interesting nonlinear-optical properties. Its gas sorption property was studied and shown to be comparable to that of previously reported metal-organic frameworks.

The photocarrier relaxation dynamics of EuTiO3 films have been investigated using femtosecond transient absorption spectroscopy. Two kinds of EuTiO3 films, with and without strain, have been included. In both films, the decay dynamics of 2p-3dt2g transition has a fast (∼2 ps) and slow (ns) components which are independent of the strain. Remarkably, the transient photobleaching of 4f-3dt2g transition is found to be enhanced considerably in the strained film, accompanied with a subnanosecond carrier lifetime. This behavior can be linked to the strain induced band structure modulation. Our results reveal the dynamical interactions in EuTiO3, identifying the critical roles of strain in photo induced phenomena.

Nonlinear refraction and absorption in carbon disulfide (CS2) has been investigated using the Z-scan technique with a femtosecond pulse laser at a wavelength of 800 nm in a broad intensity range. It is found that the origin of nonlinearity depends on the laser intensity. At low intensity, the nonlinearity is mainly due to the third-order process. The third- and fifth-order processes are at present simultaneously at high intensity. We also find the critical intensity value which determines whether the fifth-order nonlinear process exists or not by analysis of the divided Z-scan curves at different intensities. The nonlinear absorption is attributed to the three-photon absorption and the nonlinear absorption coefficient is 1.37 × 10−27 m3 W−2.