To develop porous solid-state materials for the effective capture of radioactive iodine in both vapor and solution phases is of great importance. In this work, a Zr/Ti-based bimetallic metal-organic framework (AO-UiO-66-ZrTi11) was synthesized via a simple solvothermal method using 2,5-bis(allyloxy)terephthalic acid, ZrCl4 and Cp2TiCl2. This MOF solid was fully characterized and extensively evaluated for its I2 capturing performance. AO-UiO-66-ZrTi11 demonstrated significantly enhanced I2 uptake capacity, achieving as high as 2.46 g g-1 for iodine vapor and 1084.4 mg g-1 for iodine/cyclohexane solution. Kinetic studies of iodine adsorption from solution revealed rapid kinetics, with the process fitting well to the pseudo-second order kinetic model. The superior adsorption performance of AO-UiO-66-ZrTi11 for iodine can be attributed to its unique bimetallic structural features and functional groups. This work provides valuable insights for the further development of efficient adsorbents towards capturing radioactive iodine.

Synthesizing stable MOF materials with good adsorption capability in a relatively green way is well worth investigating. In this work, a stable Ce-UiO-66-NH2 MOF was constructed from Ce(iv) salts and a bifunctional ligand, 2-amino terephthalic acid, in a mixture of water and ethanol at room temperature. The MOF solid was fully characterized and its adsorption properties for methylene blue were investigated in detail. Ce-UiO-66-NH2 showed excellent removal ability of MB over a wide pH range, the adsorption process followed a pseudo-second-order kinetic model, and the isothermal adsorption data fit well with a Langmuir model with a maximum capacity of 427 mg g-1. Moreover, a spontaneous heat adsorption process was concluded from thermodynamic study, and this MOF sorbent can be reused for several cycles with its structural stability maintained. A possible mechanism for MB adsorption was also proposed. Ce-UiO-66-NH2 was synthesized in water and ethanol at room temperature for effective removal of MB in aqueous solution.

The carrier transport capacity of the unintentionally doped InGaN upper waveguide (UWG) layer affects the hole injection efficiency of GaN-based blue laser diode. In this article, we studied the carrier transport property of UWG layer grown under various conditions by metal organic CVD. Hole diffusion length in these samples were obtained by photoluminescence. It is found that higher diffusion length can be obtained with growth temperature around 840 °C–870 °C and V/III ratio about 16 000. It is also found that reducing the threading dislocation density can enhance the carrier transport capacity of the UWG layer. Finally, blue laser diodes (LDs) were fabricated to confirm that increasing the effective diffusion length of carriers in UWG layers can help improve LDs performance.

Adhesives with properties of low-temperature and water-resistance are important in manufacturing. In this work, dopamine hydrochloride (DA), containing catechol groups, was introduced into the polymer by covalent grafting to obtain water-resistant films. Films with low-temperature and water-resistance properties were obtained through layer-by-layer assembly of branched polyethyleneimine (bPEI) and chemically cross-linked hyaluronate (HA)-DA (denoted HA-D). The film surfaces were wetted with moisture generated from low-temperature pretreatment, and the resulting films, named as bPEI/HA-D multilayer films, could adhere strongly by manual application of pressure of about 0.8 MPa. High transmittance (>= 78%) was confirmed by ultraviolet-visible absorption spectroscopy, and the adhesion was determined by lap shear tests. Results indicated that the bPEI/HA-D multilayer films had excellent adhesive strengths and were insensitive to temperature, when stored at -20 degrees C (1.08 +/- 0.54 MPa), in 100% relative humidity (0.54 +/- 0.22 MPa), under ambient conditions (0.99 +/- 0.29 MPa), which suggests their potential applications in optical fields and special environments, such as underwater or at low temperature.

As an important semiconductor material,GaN is widely studied for its photoelectric properties. In order to save energy and adapt to the development of miniaturization,it is a current development trend to integrate three-primary colors(RGB) light-emitting devices on chips. GaN as a relatively mature light-emitting host,can achieve full band light emitting from ultra-violet to infra-red by doping different rare earth ions. Therefore,rare earth doped GaN materials have an important application prospect in white light emitting diodes. Hence,in this paper Eu3+ or Tm3+ doped GaN films were prepared by ion implantation method. The effects of different temperatures and ion implantation doses on the luminescence properties of GaN: Eu3+,Tm3+ films were investigated. Finally,the mechanism of energy transfer interaction between Eu3+ and Tm3+ was also analyzed. In terms of material preparation,firstly GaN thin films with thickness of 5 mu m were grown on c-plane sapphire substrate by Metal-organic Chemical Vapor Deposition(MOCVD). Then, different doses of Eu3+ or Tm3+ ions were implanted into GaN films by ion implantation, respectively. To remove the crystal lattice damage,the samples were annealed at 1040 degrees C under flowing NH3 atmosphere for 2 h. The luminescence properties of GaN: Eu3+, Tm3+ films were studied by Temperature-Dependent Photoluminescence(TDPL) spectra. On one hand,at room temperature,five transition peaks at 544,601,622,633 and 665 nm were observed,corresponding to the Eu3+ 5D1 -> F-7(1), D-5(0)-> F-7(1),D-5(0)-> F-7(2),D-5(1)-> F-7(4) and D-5(0)-> F-7(3) transitions,respectively. On the other hand,three kinds of Eu3+ D-5(0)-> F-7(2) and D-5(1)-> F-7(4) emission peaks labeled as P-1-P-7 with different temperature-dependent properties were found in which P-2 and P-6 emission peaks show similar temperature dependence;the temperature dependence of P1 emission peak is different from that of P-2; but the P-3,P-4,P-5 and P-7 emission peaks have similar temperature dependence. In addition,Cathodoluminescence(CL) spectra showed that co-doping Eu3+ and Tm3+ in GaN films achieved the mixing of the luminescence colors of the two rare earth ions,and the emission peak positions of Eu3+ and Tm3+ were not significantly different from those Eu3+,Tm3+ single doped GaN films. With the increase of Tm3+ dose, Eu3+ emission intensity and I-480/ I-806 intensity ratio of Tm3+ decreased,which reveals an energy transfer of Eu3+-> Tm3+. There is a small energy difference (similar to 60 meV)between the D-5(2)-> F-7(0)(similar to 2.66 eV)transition of Eu3+ and the (1)G(4)-> H-3(6)(similar to 2.60 eV)transition of Tm3+. Therefore, phonon-assisted non- radiative resonance energy transfer is highly possible between Eu3+ and Tm3+ ions. After detailed analysis,herein there are three energy transfer pathways between Eu3+ and Tm3+ ions which are(D-5(2) [Eu3+] , (1)G(4) [Tm3+]) -> (F-7(0) [Eu3+] , H-3(6) [Tm3+] ) , (D-5(0) [Eu3+] , H-3(6) [Tm3+]) -> (F-7(2) [Eu3+] , F-3(2)[Tm3+]) and (D-5(0) [Eu3+] , H-3(6) [Tm3+] ) -> (F-7(3) [Eu3+] , F-3(3)[Tm3+] ), respectively. Furthermore, through calculating and analyzing, we proved that the energy transfer mechanism is mainly an electric dipole-electric dipole interaction. According to the color temperature calculation formula,the luminescence chromaticity coordinates and the Correlated Color Temperature (CCT)of the samples were calculated. With the increase of the implanted dose of Tm3+, the luminescence color of the samples was gradually regulated by the blue luminescence of Tm3+. By changing the dose ratio in GaN: Eu3+ , Tm3+ films,the luminescence color of the materials was effectively regulated.This research provides a feasible method for GaN based light-emitting materials,and reveals the great potential of rare earth ions in the field of full-color display.

Gallium Nitride (GaN)-based materials have the characteristics of large band gap, high electron mobility, high thermal conductivity, etc., which are used in various electronic devices and optoelectronic devices, and have received extensive attention. High power GaN-based blue laser diodes (LDs) have great prospects in laser display, laser lighting, metal processing and other fields. However, the development of high-power GaN-based blue lasers is extremely difficult, mainly related to the difficulties of epitaxial growth, processing and packaging technology. Firstly, the epitaxial structure of blue laser is complicated, and the crystal quality needs to be ensured while improving the luminous efficiency of the quantum well and reducing the light absorption loss. Secondly, the sidewall loss and cavity surface loss need to be reduced during the manufacturing process. Last but not least, a low thermal resistance packaging technology needs to be developed, so that high-power GaN-based blue lasers can effectively dissipate heat. In this work, by adopting the double-sided packaging method for GaN-based blue lasers, which use the copper fully attached to the N-side of the blue laser to increase the heat dissipation. According to the change in the forward voltage caused by the junction temperature change, the thermal resistance of the single-sided packaged blue laser is 8.5 K/W, while the double-sided packaged blue laser has a thermal resistance of 6.7 K/W. It can be found that the GaN-based blue laser with double-sided packaging has lower thermal resistance and can dissipate heat more effectively, which is beneficial for the high-power blue laser to work under continuous room temperature conditions. According to the power-current curves of the blue laser from room temperature to 65 degrees C, the characteristic temperature of the single-sided packaged blue laser is 132 K, and the characteristic temperature of the double-sided packaged blue laser is 235 K, it is found that the characteristic temperature of the double-sided packaged blue laser is higher, which means that has better temperature stability. Finally, we demonstrate the double-sided packaged blue lasers with a ridge width of 45 mu m and a cavity length of 1 200 mu m which have a threshold current density of 1.1 kA/cm(2) and a slope efficiency of 1.4 W/A. The light output power reaches 7.5 W at 6 A under continuous-wave operation at room temperature, it means that the double-sided packaged blue laser has good material quality, structure and packaging.

X-Ray diffraction (XRD), Raman scattering, Cathodoluminescence measurements (CL) and Photoluminescence (PL) were employed to characterize the structure and optical properties of Dysprosium (Dy) and Europium (Eu) implanted GaN films grown by MOCVD. For GaN: Dy3+ samples, Dy3+ implantation leads to strain and radiation damage increasing with Dy3+ implanted fluence. From the CL spectra, the characteristic transitions from the excited 4F9/2 level of Dy3+ to 6H15/2 (485 nm), 6H13/2 (583 nm) and 6H11/2 (671 nm) were observed. For Dy3+ and Eu3+ codoped GaN, considering the doping effects of Dy3+, we proposed that there might exist a resonance energy transfer process from Eu3+ ions 7F0 -> 5D2 to Dy3+ ions 4F9/2 -> 6H15/2, which is dominated by the electric dipole-dipole interaction.

Compared with silicon carbide (SiC) and gallium nitride (GaN), gallium oxide (Ga2O3) has the advantages of larger band gap width, stronger breakdown field strength, larger absorption cutoff edge, and lower growth cost. Doping technique is an effective method of optimizating physical properties of materials, which can broaden the application of Ga(2)O(3 )in different fields. In this paper, the progress of rare earth and other elements doped Ga(2)O(3 )in recent years are reviewed and the luminescence characteristics of rare earth doped Ga(2)O(3 )are analyzed. Finally, the research direction of rare earth doped Ga2O3 and p-type Ga2O3 are prospected.

emitting material GaN∶Eu 3+ is very promising to be applied in GaN-based monolithic integrated full-color display devices The current research focus is how to further control and optimize the luminescence characteristics of GaN∶Eu 3+ materials and promote them to the practical stage In this paper the research progresses of optimizationing luminescence performance of GaN∶Eu 3+ materials from growth control Mg 2+ Zn 2+ and Si 4+ co-doping control and other rare earth element co-doping control etc are reviewed the application potential of these methods is compared the future work focus of GaN∶Eu 3+ materials is pointed out and the trend of future development is prospected

Dy3+ and Eu3+ ions with different doses were implanted into AlN thin films grown by hydride vapor phase epitaxy method. For Dy doped AlN, results of X ray diffraction and Raman scattering show that the compressive stress of the sample increases with the increase of Dy3+ dose. When the Dy3+ dose increases from 5 x 10(14) at/cm(2) to 1 x 10(15) at/cm(2), the compressive stress of samples is close to saturation. For Dy3+ and Eu3+ co-doped AlN, according to the cathodoluminescence spectra, a possible energy transfer process between Dy3+ and Eu3+ is proposed. In addition, through changing the dose ratio of Dy3+ respect to Eu3+ ions, the chromaticity coordinates and color temperatures of Dy3+ and Eu3+ co-doped AlN can be effectively regulated.

Transparent Er3+/Tm3+ co-doped tungsten-tellurite (TWL) glasses with variable Er (3+) concentration were prepared by the conventional melt-quenching method. The samples prepared were investigated by differential scanning calorimetry (DSC), absorption spectra, up-conversion, near and mid-infrared emission and lifetime decays. DSC analyses indicates a high transition temperature (Tg) and a large value of Delta T. Enhanced 2.7 mu m emission in Er3+/Tm3+ co-doped TWL glasses presents its superiority in mid-infrared application. Based on above emission spectra and lifetime decays, the energy transfer mechanism between Er3+ and Tm3+ ions was discussed. Tm3+ ions are an effective sensitization for 2.7 mu m emission of Er3+ ions in this glass for its high energy transfer efficiency (83.6%). A comparative study on emission performance suggests that this Er3+/Tm3+ codoped TWL glass is a competent candidates for mid-infrared laser materials.

The development of a novel film fabrication strategy, named demulsification-induced fast solidification (DIFS), for the rapid fabrication of large-area polymer films is reported in this study. The polymer films are fabricated through dialysis and dipping processes using emulsions and a demulsifier based on the DIFS method. Furthermore, robust and flexible free-standing films with controllable thicknesses and functionalities, such as tunable mechanical properties (elongation at break of 350-980% and ultimate tensile strength of 0.21-1.88 MPa); excellent optical properties (optical transmittance greater than 52.03% in the visible region, refractive index of 1.4888 +/- 0.0001, and Abbe number of 52.1 +/- 1.1); and luminescence properties, are rapidly and easily prepared by mechanical exfoliation based on the DIFS method. The results show that this academic concept and fabrication method will provide support for the design and preparation of functional polymer films that are highly desirable for optical, flexible device, and wearable material applications.

Ultraviolet and blue light can not only cause glare, but also harm human eyes due to their short wavelength and high energy. So, it is important to develop anti-glare materials. In this paper, the anti-glare glass with different dosage of Ce3+, Sm3+ and Ho3+ were prepared by high temperature melting method. The performance of the anti-glare had been measured by thermal expansion coefficient, refractive index and transmission spectrum. It's found that when the content of Ho3+ is 0.8 mol%, a large amount of absorption of short-wave blue light can be achieved and the transmittance of visible light is high. The results show that the anti-glare glass is a kind of potential anti-glare material for displays, automotive lights and LED light sources.

Optical bonding with both excellent mechanical and optical properties is highly desirable for many advanced optical device applications. This paper presents a facile method for fabricating large-area, highly transparent, and mechanically stable adhesive films with a tunable refractive index (RI) by the layer-by-layer (LbL) assembly of cationic branched poly(ethylenimine) (PEI) and an anionic blend of poly(acrylic acid) (PAA) and poly(4-styrenesulfonic acid) (PSS). Scanning electron microscopy and atomic force microscopy studies indicate that the resulting (PEI/PAA-PSS)*n adhesive films with n PEI/PAA-PSS deposition layers are smooth and homogeneous. A satisfactory bonding strength is demonstrated for both two-sided and one-sided bonding methods, which provide a bonding strength greater than 5.71 +/- 0.71 MPa. A linearly tunable RI from 1.5410 to 1.5792 is achieved with a transparency greater than 94% in the visible region. Moreover, the preparation and debonding of adhesive films can be conducted in water, which is convenient and environmentally friendly.

Materials with high adhesive strength that can be fabricated by environmentally friendly methods are crucial for various bonding applications. In this study, highly adhesive films with an adjustable refractive index (RI) were prepared by the layer-by-layer (LbL) assembly of cationic poly(diallyldimethylammonium chloride) (PDDA) and an anionic blend of poly(acrylic acid) (PAA) and poly(4-styrenesulfonic acid) (PSS). The RI of the adhesive films can be precisely controlled between 1.5181 and 1.5562 by simply changing the PSS content. We obtained high adhesive strengths in the range 3.99 +/- 1.04 MPa to 6.88 +/- 0.95 MPa by gently pressing two glass substrates together with transparent (PDDA/PAA-PSS)*n LbL assembled films with different NaCl contents in the presence of a thin layer of deionized water (n refers to the number of film deposition cycles). Importantly, the water is an environmentally friendly solvent in the bonding and debonding processes. Finally, these adhesive films exhibit high optical transparency in the visible region and exhibit excellent thermal stability. The outstanding features of these films ensure their use in practical optical bonding applications.

The solvothermal assemblies of Zn(II)/Co(II)/Ni(II) ions and a rigid silicon-centered tetrahedral ligand, tetrakis(3-carboxyphenyl) silicon (H4L), yield five metal-organic frameworks, formulated as [Zn-2(OH)(dib)(0.5)(HL)]center dot H2O center dot 2DMF (1), Zn-3(OH)(2)(phen)(2)(H2L)(2) (2), [Co-2(OH)(H2O)(3)(DMF)(HL)]center dot H2O center dot 2DMF (3), [Co-2(OH)(H2O)(phen)(DMF)(HL)]center dot H2O center dot DMF (4) and [Ni-2(OH)(H2O)(2)(DMF)(2)(HL)]center dot H2O center dot DMF (5) [phen = 1,10-phenanthroline, dib = 1,4-di(1H-imidazol-1-yl) benzene, DMF = N, N-dimethylformamide]. Single crystal X-ray diffraction analyses reveal that 1 is a three-dimensional framework structure based on 5-connected [Zn-2(OH)](3+) secondary building units (SBUs) and the silicon-centred tetrahedral ligands. 2 features a one-dimensional architecture constructed from trinuclear [Zn-3(OH)(2)(phen)(2)](4+) SBUs and 2-connected tetracarboxylate ligands. The structures of 3-5 are similar, which all contain dinuclear metal-based SBUs linked by 4-connected silicon ligands, resulting in layered sql nets. The syntheses, structures, thermal stabilities and photoluminescence of these compounds are studied. Further luminescence studies reveal that 1 exhibits a high-sensitivity sensing response to tetrahydrofuran.

The direct modulation of high-power semiconductor laser driver that is composed of the current modulation circuit and the over-current protection circuit is introduced, two direct modulation circuits with different modulation output current amplitude are designed and the direct modulation of characteristics is analyzed, providing the output current waveform of the direct modulation of high-power semiconductor laser. In this paper, a new modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 2.56MHz. The width of the modulation current pulse keeps stable after widening. When the input signal is voltage pulse with uniform pulse width, it can output current pulse with uniform pulse width. And the modulation output current with a peak current of 9.5A is designed with bias current of 0.8A and the modulation current bandwidth of 5MHz. We have a theoretical study on the dynamic characteristics of direct modulation of semiconductor laser. We also have done some experiments on the basis of the simulation, the experimental results show that the output pulse laser intensity and the pulse laser modulation signal width change with changing the width of the pulse, and the actual modulated output pulse laser has a certain time delay with respect to the modulated signal.

Er:Yb1Al5O12 (Er:YbAG) nanopowder was prepared by carbonate coprecipitation method. Highpurity Er:YbAG powder was obtained after calcination at as low as 1000°C with an average particle size of 70 nm. The Al–O–Yb phonon vibrations were investigated and the absorption band arisen from interaction between lattice vibration and photon in YbAG is located around 610 cm–1. A strong emission peak of powder was observed at 1.53 µm with 980 nm laser excitation. An energy transfer mechanism between Yb3+ and Er3+ states responsible for the peak emission was proposed. An optimum Er3+ dopant concentration was determined.

Nd:YAG nanopowder was prepared by urea co-precipitation method. XRD, TG-DTA, SEM and spectra analysis were utilized to study the properties of the powder. Results indicated that fine Nd:YAG nanopowder can be acquired at 1000°C for 10h. The fluorescence spectra shown that the strongest peak was located at 1061nm, corresponding to the 4F3/24I11/2 energy level transition of Nd3+ ion.

A new Er3+/Yb3+-codoped fluorphosphate glass was prepared by high temperature melting. Its density, absorption spectra, and fluorescence spectra were measured and investigated. The effect of Er3+ and Yb3+ concentrations on the spectroscopic properties of the glass sample are discussed. A Judd-Ofelt theory analysis on the absorption spectra was performed. The oscillator strengths were Omega(t) (t=2, 4, 6), Omega(2)=4.36x10(-20) cm(2), Omega(4)=1.35x10(-20) cm(2), and Omega(6)=0.79x10(-20) cm(2). The lifetime (T-m) of the (4)/(13/2) level for the Er3+ ions was 8.26 ms and the full width at half maximum (FWHM) of the main emission peak was 68 nm at 1.53 mu m. The large stimulated emission cross-section (sigma(e)=8.5x10(-21) cm(2)) of the Er3+ was calculated using McCumber theory. The spectroscopic properties of the Er3+ ion were compared among different glasses. The FWHM and sigma(e) of Er3+/Yb3+-codoped fluorphosphate glass were found to be larger than those of other glass hosts, which indicates that this glass may be a potentially useful candidate material host for a high-gain erbium-doped fiber amplifier.