最新刊期
卷 33 ， 期 9 ， 2012
- 摘要：Transparent pale yellow ZnO crystals with different hexagonal morphology, such as hexagonal caps and hexagonal lamellae, have been successfully synthesized in molten hydrous NaOH-LiOH. The phase structure of the as-grown crystals was investigated by means of X-ray powder diffraction. Detailed surface morphology of the crystals was studied using optical microscopy and scanning electron microscopy. Elemental analysis of the synthesized crystals was performed using energy dispersive X-ray spectrum. The photoluminescence spectrum was employed to characterize the obtained crystals. Some ultraviolet, blue, green and red emission peaks were observed in the photoluminescence spectrum.关键词：ZnO;NaOH-LiOH;surface morphology;crystal;photoluminescence95|99|0更新时间：2020-08-12
- 摘要：The photoluminescence (PL) spectra of ZnCuInS quantum dots (QDs) were measured in the temperature range from 100 to 300 K. The temperature dependences of the PL energy, linewidth, and intensity of the ZnCuInS QDs were investigated in detail. An anomalous increase in band gap of ZnCuInS QDs with temperature was observed. The full width at half maximum of the PL and thermal activation energy Ea of ZnCuInS QDs were 300 and 100 meV, respectively. These results suggested that the PL in the ZnCuInS QDs originated from the recombination of many kinds of defect-related emission centers in the interior and on the surface of the QDs.关键词：ZnCuInS;quantum dots;nanocrystals;temperature-dependent photoluminescence105|186|4更新时间：2020-08-12
- 摘要：The orthorhombic Gd2(MoO4)3∶Dy3+ were successfully synthesized by hydrothermal process with a subsequent annealing treatment. The crystallization and microstructures of the samples were characterized by powder X-ray diffraction (XRD) and scanning electron micrograph (SEM). The luminescent properties of the prepared samples were investigated by the excitation and emission spectra. Under 389 nm excitation, the emissions centered at 487 nm and 576 nm were attributed to the transitions of 4F9/2-6H15/2 and 4F9/2-6H13/2, respectively. The emission spectra indicated that the optimal doping content of Dy3+ was 16％. Especially, the orthorhombic Gd1.84(MoO4)3∶Dy0.163+ exhibits CIE coordinates of (0.326, 0.336) with a color temperature of 6 389 K, which is closest to the nature white light. Thus it can be considered to be a potential candidate for white-LEDs.关键词：Gd2(MoO4)3∶Dy3+;hydrothermal synthesis;white emitting phosphors83|53|3更新时间：2020-08-12
- 摘要：The transparent and conductive ZnO/Au/ZnO (ZAZ) multilayer films were deposited on the sapphire substrates by MOCVD and RF magnetron sputtering. All the ZnO films were fabricated by MOCVD, and the thickness of each ZnO film was approximately 150 nm. The Au interlayers were fabricated by RF magnetron sputtering, annealed at room temperature, 200 and 300 ℃. The thickness of each Au interlayer was 2 nm. The effects of the annealing temperature on structural, electrical and optical properties of ZAZ films were investigated. When the annealing temperature was 200 ℃, the FWHM of ZAZ films were 0.14°, which exhibited the better crystal quality and c-axis pre-ferential orientation. Moreover, the lowest resistivity was 2.7×10-3 Ω·cm with a carrier concentration of 1.07×1020 cm-3 and the visible transmittance was 75.3%. This indicated the multilayer films had the best properties when the annealing temperature was 200 ℃.关键词：MOCVD;ZnO/Au/ZnO multilayer films;RF sputtering;annealing temperature114|95|2更新时间：2020-08-12
- 摘要：A new white LED was fabricated by irradiated the mixed fluorescent powder which contained [Ru(dtb-bpy)3]2+(PF6-)2 and YAG. The relationship between white LED' spectral and the [Ru(dtb-bpy)3]2+(PF6-)2 content were investigated. When the mass fraction of [Ru(dtb-bpy)3]2+(PF6-)2 was 1.5%,the White LED color-rending index reached 83.2 and its luminous efficiency was about 20% lower than those without [Ru(dtb-bpy)3]2+(PF6-)2. Moreover, we studied the influence of junction temperature on the luminous properties of the integration package white LED. The results showed that the blue chip radiation reduced about 27.73% during LED's junction temperature rising from 30 ℃ to 130 ℃. The white LED light intensity decreased and the luminous efficiency reduced 31.76%, while the color-rending was stability.关键词：color-rending;phosphorescent;[Ru(dtb-bpy)3]2+(PF6-)2;organic material;junction temperature94|132|3更新时间：2020-08-12
- 摘要：Tm3+,Yb3+ codoped oxyfluoride ceramic glass was prepared and their up-conversion luminescence property was studied under the pump of 980 nm diode laser. In the luminescence spectra of annealed samples,stark splits of luminescence were observed at 463 nm and 476 nm. Temperature property of this split was studied between 303 K and 623 K. The results indicate that Tm3+,Yb3+ codoped oxyfluoride ceramic glass could be used for temperature measurement according to luminescence intensity ratio. The best sensitivity is 4.2?10-4 K-1 at 352 K.关键词：Tm3+;oxyfluoride glass ceramic;blue upconversion;absolute temperature143|94|4更新时间：2020-08-12
- 摘要：Series of Sr3Gd0.5-xTb0.5(BO3)3∶xEu3+ phosphors were prepared by the high temperature solid-phase method, and their luminescent properties and the energy transfer process were investigated. Sr3Gd0.5-xTb0.5(BO3)3∶xEu3+ phosphors can produce 489,544,594,614,624 nm emission lines under near-ultraviolet light (300~400 nm) excitation. The lifetime of Tb3+ decreased with the increasing addition of Eu3+, which proved there exist energy transfer process from Tb3+ to Eu3+. When the mole fraction of Eu3+ was 0.07, the lifetime of Tb3+ dropped to 1.20 ms and the energy transfer efficiency was calculated to be 20.53%. Meanwhile, the energy transfer process from Tb3+ to Eu3+ was further studied by analyzing energy level structures of Tb3+ and Eu3+. The phosphors exhibit good red luminescence properties, which can be used in white light emitting diodes (LEDs).关键词：LED;Sr3Gd0.5-xTb0.5(BO3)3∶xEu3+;energy transfer88|33|0更新时间：2020-08-12
- 摘要：The electroluminescence of tris(8-quinolinolato) aluminum (Alq3) has been observed in organic light emitting diodes under a kind of non-sinusoidal waveform (a square wave). During the high period of square wave, the electrons in Alq3 are driven towards the anode, while moved towards the cathode during the following low period of square wave. The electroluminescence of Alq3 vanishes completely from the point where the period of square wave equals twice the transit time of electrons across the Alq3 layer. Thus, the electron mobility of Alq3 can be evaluated, and the obtained results are in good accordance with the reported values. The thickness dependence of the electron mobility for Alq3 is also investigated. We provide a simple, easily accessible method to determine the charge-carrier mobility for organic materials.关键词：square wave driving;mobility;tris(8-quinolinolato) aluminum;p-type doping156|90|2更新时间：2020-08-12
- 摘要：The electronic structure and optical properties of impurity Rh-doped Ru2Si3 have been studied by using the first principle plane-wave pseudo-potential based on the density function theory. The calculated results show that doped Ru2Si3 make the cell volume increases. Rh-doping replacing RuⅢ position makes the system steady, and the conductivity type convert into n-type; the static dielectric function is 25.201 4, the value of the refractive index has increased to 5.02.关键词：doped Ru2Si3;electronic structure;optical properties;first principle115|90|2更新时间：2020-08-12
- 摘要：Phosphors of nominal composition Sr3-xSi1-xAlxO5∶xCe3+ were prepared by heterogeneous precipitation method and high temperature solid state reaction method, respectively. The phosphors were characterized by XRD, SEM and fluorescence spectrum analysis. The results show that phosphors synthesized by heterogeneous precipitation method have higher phase purity, narrower particle size distribution, clearer crystal surface and lighter aggregation, also yield higher relative luminous intensity, than those by high temperature solid state reaction method. The excitation spectra of the phosphors range from 270 nm to 500 nm with the bimodal broadband, while the strongest excitation peak at 417 nm. The emission spectra range from 450 nm to 700 nm with single-peak broadband, with peak at 525 nm. Charge compensation has a great influence on the relative luminous intensity of phosphors. It could be conclude that adding Al3+ to substitute Si4+ as charge compensation might be better than adding Li+ to substitute Sr2+.关键词：white LED;charge compensation;silicate;agglomeration91|61|1更新时间：2020-08-12
- 摘要：Long afterglow phosphors Ba3.982-x(Si3O8)2∶0.008Eu2+,xCe3+,0.01Dy3+ were prepared by solid-state reactions under a weak reductive atmosphere. The photoluminescence spectra showed that two types of Ce3+ centers existed in the Ba4(Si3O8)2 lattice due to Ce3+ could occupied two different Ba2+ sites. Through the energy transfer between Ce3+ and Eu2+ multicolor fluorescence and green phosphorescence can be got. Co-doping of Ce3+ can increase the afterglow intensity, however, decrease the duration of Ba4(Si3O8)2∶Eu2+,Dy3+. Through the analysis of the thermoluminescence curves, the co-doped of Ce3+ can increase the number of shallow (T1) and deep traps(T3). As the re-trapping of the deep trap, the duration of the phosphor decreased and the intensity of the afterglow increased.关键词：long-lasting phosphor;color tunable;Ba4(Si3O8)2;thermoluminescence102|60|0更新时间：2020-08-12
- 摘要：The light conversion film Er∶YbF3, which has not only the up-conversion property but also the down-conversion property, was successfully prepared on Si (100) substrat. The effect of substrate temperature on films structural and optical properties was further studied. The results showed that the film achieves combination of up-conversion and down-conversion. It can effectively convert ultraviolet light and near infrared light into 656 nm which is the best response range to amorphous silicon. With increasing temperature, the crystallinity of the films were improved, but when substrate temperature exceeds 500 ℃, the impurity phases are found in the films. These results showed that optical properties of films with 500 ℃ were optimal. Moreover, the light conversion Er∶YbF3 film may improve photoelectric conversion efficiency of amorphous silicon solar cell.关键词：solar cells;up-conversion;down-conversion;Er∶YbF3 films;substrate temperature94|85|0更新时间：2020-08-12
- 摘要：AlxGa1-xAs sample were grown by metal-organic chemical vapor deposition (MOCVD) under the monitor of time resolved reflectance anisotropy spectroscopy (RAS) and normalized reflectance. During the growth, a significant dependence of the RAS and normalized reflectance signals on the aluminium composition has been found, which can be used to optimize the growth processes. The experimental results indicate that the period of normalized reflectance oscillation was directly related to the composition and growth rate. The first minimum of the normalized reflectance oscillation of AlxGa1-xAs almost linearly with aluminium composition and could be used to determine the starting value of graded aluminium composition. The compositions and growth rate of AlxGa1-xAs are calculated by normalized reflectance transient spectra, the value is in excellent agreement with the experimental data obtained by ex-situ scanning electron microscope (SEM) and high resolution X-ray diffraction (HRXRD).关键词：Ⅲ-Ⅴ semiconductor compounds;epitaxial growth;metal-organic chemical vapor deposition;reflectance anisotropy spectroscopy85|208|0更新时间：2020-08-12
- 摘要：Organic field-effect transistors (OFETs) based on copper phthalocyanine were fabricated and their current-voltage characteristics were measured in dark/under illumination. The results showed that OFETs with Au as source/drain electrodes exhibited a photo-current/dark-current ratio of 0.4 and a photoresponsivity of 2.55 mA/W under illumination by a laser diode with a wavelength of 655 nm and power density of 100 mW/cm2; however, OFETs with Al as source/drain electrodes exhibited a photo-current/dark-current ratio up to 104 and a much lower photoresponsivity of 0.39 mA/W under the same conditions. The tremendous increase of photo-current/dark-current ratio is ascribed to the decrease of dark-current caused by Schottky contacts between Al source/drain electrodes and CuPc.关键词：photoresponsive organic field-effect transistors;copper phthalocyanine;photocurrent/dark-current ratio;photoresponsivity107|249|0更新时间：2020-08-12
- 摘要：The vertically aligned silicon nanowire (SiNW) arrays have been fabricated by using an electroless etching method, and then the nanowire arrays were modified by dipped the SiNWs in alkali solution. The effect of alkali solution on the morphology and photoelectric property of SiNWs were studied. The results showed that the spectral response of the modified SiNW arrays cell was obviously improved compared to the bunched SiNWs cell and textured cell. The phenomenon of wavelength red shift for maximum quantum efficiency was discovered, which confirmed that the photoelectric performance can be significantly improved at long wave band by alkali solution modified, but low spectral response at short wave period showed that charge carriers were seriously recombined at silicon nanowires near surface. When the alkali solution modified time increase to 60 s, the photoelectric response was weakened. In addition, the effect mechanism of alkali solution modify on the spectral response of SiNWs cell was tentatively analyzed and interpretation in detail.关键词：alkali liquor modified;quantum efficiency;spectral response;surface recombination;red shift88|162|0更新时间：2020-08-12
- 摘要：A low-cost and effective method to fabricate hexagonally patterned urchin-like ZnO nanowire arrays was demonstrated. The ordered monolayer of polystyrene(PS) spheres is obtained by self-assembly, and the monolayer is used as a template to grow ZnO nanowires with complex hierarchical structures via hydrothermal method. The urchin-like ZnO nanowire arrays are composed of PS sphere and ZnO nanowires. The nanowires have uniform diameter, and the length of the nanowires can be controlled by the growth time. This method provides a promising way to fabricate ZnO one-dimensional nanostructures for applications as sensor arrays, solar cells and photocatalysis.关键词：ZnO;polystyrene sphere;nanowire;hydrothermal96|214|1更新时间：2020-08-12
- 摘要：Er3+,Yb3+ co-doped TiO2 films were successfully deposited on glass substrates by sol-gel method and spin-coating technique. Ti(OBu)4 and lanthanide nitrates were used as the starting materials, AcAc as the chelator and nitric as the catalyzer. The contact angle between the solvent and the glasse was measured by contact angle goniometer. The thermal decomposition, the crystal structure, and the morphology of the films were investigated by thermal analysis (TG), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. The results indicate that IPA is the suitable solvent to improve the surface wetting property. After annealed at 700 ℃ for 2 h, both of the undoped and the co-doped films get good crystallinity, and the average grain size is not more than 50 nm. The film on the glass substrate was highly compact. The strong photoluminescence phenomenon was also observed.关键词：up-conversion;Yb3+;Er3+ co-doped;titanium oxide;sol-gel;spin coating99|33|4更新时间：2020-08-12
- 摘要：The polarization control of vertical-cavity surface-emitting lasers with high power emission was demonstrated by using metal-grating to import non-isotropic gain. The grating with a period of 186 nm and a duty ratio of 0.5 which were calculated based on effective medium theory and antireflection theory. Then, it was simulated by multiphysics field of finite element analysis software, and the results correspond well with our design requirements. A polarization ratio of 3, an output power of 870 mW was demonstrated for a 550 μm aperture device.关键词：vertical-cavity surface-emitting laser;metal-grating;polarization controlling110|186|1更新时间：2020-08-12
- 摘要：The interaction between bovine serum albumin (BSA) and cefpiramide sodium (CPMS) was investigated at different temperatures. The effect of common metal ions (Mg2+, Zn2+, Cu2+, Co2+, Fe3+, Ni2+) on the BSA-CPMS system was also researched. The results show that CPMS can quench the intrinsic fluorescence of BSA significantly, and the quenching mechanism is a static quenching process which follows the Förester spectroscopy energy transfer. The electrostatic force played an important role on the conjugation reaction between BSA and CPMS. The binding constants (Ka) was in the order of 104, and the number of binding site (n) in the binary system was approximately equal to 1. The binding distance (r) was about 2.60 nm and the primary binding for CPMS was located at sub-domainⅡA of BSA. Synchronous spectra and Circular dichroism(CD) spectra revealed that the microenvironment and the conformation of BSA were changed during the conjugation reaction.关键词：bovine serum albumin;cefpiramide sodium;metal ions;interaction86|86|8更新时间：2020-08-12
- 摘要：Ammonia detecting has a wide range of applications, and currently attracts considerable attention through the photoacoustic. The premise of detecting is to determine the absorption lines of ammonia. At normal pressure and temperature, the absorption spectrum of ammonia at the range of 1 515~1 532 nm was measured with an external cavity tunable semiconductor laser through the photoacoustic spectroscopy gas detection theory. Seven ammonia absorption lines,at 1 515.2, 1 516.0, 1 518.0, 1 519.9, 1 522.4, 1 527.0, 1 531.7 nm, were scanned by resetting the laser tuning range and were confirmed having strength absorption. The spectroscopic database of HITRAN 2004 do not contain ammonia spectrum in the 1.5 μm region, and the results of this paper provided more ammonia absorption lines to choose for the ammonia detection research based on photoacoustic.关键词：photoacoustic spectroscopy;external cavity tunable semiconductor laser;absorption line;ammonia detection77|170|1更新时间：2020-08-12
- 摘要：By combining rhodamine 6G and cumarin, a fluorescent probe of Hg2+, Rh-6G-cumarin(RC), based on FRET mechanism was synthesized. And through research its spectral properties and recognition to mercury ion, we found that it featured a rapid fluorescence enhancement at 575 nm upon the addition of Hg2+ in V(C2H5OH)∶V(H2O)=9∶1 solution. The fluorescence changed from blue to bright red, while the color of the solution changed from yellow to red. This probe showed high specific for Hg2+ over other metal cations, such as Na+,K+, Mg2+, Cr3+, Fe2+,Co2+,Zn2+, Cd2+ and Pb2+. It could detect Hg2+ effectively in a relatively wide pH range (4~10). The titration experiment indicated a 2∶1 stoichiometry of the RC-Hg2+ complexation species.关键词：fluorescent probe;Hg2+;FRET;Rhodamine 6G;cumarin112|146|3更新时间：2020-08-12
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176862 Email：fgxbt@126.com
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0