最新刊期
卷 14 ， 期 2 ， 1993
- 摘要：The recent progresses in porous silicon,including the formation process of porous silicon,photoluminescence and electroluminescence are reviewed,with emphasis on the formation process and quantum confinement effect in porous silicon.关键词：formation of porous silicon;photoluminescence;quantum confinement effect126|129|3更新时间：2020-08-11
- 摘要：New color centers,F2,F3 and F4 in BaFBr:Eu2+ crystal are reported in this paper.Their absorption bands are in 810-900nm 670-715nm,and 970-995nm respectively.They are F aggregates formed by the association of F centers.According to the present study,F2,F3 and F4 centers are more stable than F centers and the deviation of stimulation bands from the emission band of Eu2+ is farther than that of F bands from the emission band of Eu2+.Therefore F2,F3 and F4 centers are more efficient for X-ray storage.关键词：BaFBr:Eu2+;photostimulated luminescence;color centers107|103|5更新时间：2020-08-11
- 摘要：With the transient solutions of optical Bloch equation,dependences of hole width and depth on the burning pulse duration have been discussed for spectral hole burning of two-level system.With a strong and short π pulse,a deep hole may be burnt.Its width is much narrower than the steady state one predicted by optical Bloch equaion.While burning power density is weak,hole depth will be exponentially dependent on burning time.Modification of the Bloch equation does not significantly affect the results of above mentioned two cases.Based on the behavior of spectral hole burning of two-level system,situations of persistent hole burning and photon gated spectral hole burning have also been considered.关键词：spectral hole burning148|79|2更新时间：2020-08-11
- 摘要：We investigated the thermal induced optical nonlinearity of a CdSSe-doped glass JB-7 made by Changchun Institute of Optics and Fine Mechanics.A slice of this glass coated on its both surfaces with high reflective dielectric films formed a Fabry-Perot resonator.The reflected light signal from the F-P resonator was coupled into a hybrid ring cavity,the round trip time of which was much longer than that in the F-P resonator and even longer than the thermal relaxation time of the glass.The self-oscillations occuring for certain input parameters were regular and the appearence of different modes as a function of the light intensity falling onto the resonator was observed.Due to the broad hysteresis and the high inclination of both branches of the bistability large numbers of increasing and decreasing steps in the output intensity were observed.A simple model of adiabatical simulation by an iterated map shows that the mode structure follows the Farey-tree construction.关键词：CdSSe-doped glass;optical nonlinearity127|101|0更新时间：2020-08-11
- 摘要：This paper reports the first observation of sensitized luminescence phenomenon of Tb3+ ion by two-photon absorption of Gd3+ ion in Tb0.7Gd0.3P5O14 noncrystalline induced by pulsed DCM dye laser.In terms of two-photon absorption,there is a rather large deviation from the prediction of second order theory for 6P7/2,6P5/2 energy of Gd3+ ion.And it is necessary to take into account the contribution of third order spin-orbit interaction.关键词：rare earth penta-phosphate noncrystal glass;sensitized luminescence of Tb3+ ion by Gd3+ ion;two-photon absorption102|69|2更新时间：2020-08-11
- 摘要：In this paper,the relations and differences between DCEL and ACEL characteristics of powder ZnS:Mn,Cu DCEL devices,and their mechanism are investigated.Experiments show that the impedance characteristics both under DC and AC voltage operations are not consistent and related.But the exciting current IA and the brightness BA under AC voltage,and the brightness BD and the efficiency ηD under DC voltage tend to consistency to certain extent.The efficiency ηA under AC voltage is contrary to above four parameters.DCEL devices are strongly non-linear and non-symmetrical in photoelectric characteristics.In positive half-cycle of AC voltage(or under DC voltage),DCEL devices are excited by high electric field and low current.Under this circumstance,the luminance is dominared by electric field.On the contrarily,in negative half-cycle of AC voltage DCEL devices are operated by low electric field and large current.At this case,the luminance is dominated by current,no;by field.Under AC voltage,the luminance of DCEL devices may show characteristics of positive or negative half-cycle,or complex characteristics of both positive and negative half-cycle,depending on the phosphors,the art of devices,the forming process and operation voltage.The above point of view can explain all of the experimental results mentioned in.this paper.关键词：AC electroluminescence;DC electroluminescence;forming process;non-symmetry;consistence189|72|1更新时间：2020-08-11
- 摘要：Optical properties of Cu2O semiconductor ultrafine particles with surface modification were investigated by measuring the absorption,photoluminescence and excitation spectra at room temperature.No obvious quantum size effect was observed in the Cu2O ultrafine particles,but very strong and broad photoluminescence bands were observed.The peak positions of the photoluminescence bands were shifted to short wavelength and the widthes of the bands were increased with decreasing excitation wavelenth.Finally,we analyze the mechanisms of the broad photol-uminescenee bands in Cu2O ultafine particles and discuss the influence of heat treatment on the intensity of the luminscence of the ultrafine particles.105|71|5更新时间：2020-08-11
- 摘要：Luminescence-current characteristics and temperature influence on luminescence of a-SiC thin.film light-emitting diodes fabricated by RF-PECVD methed have been measured clearly.Under direct current conditions,the luminescence of the devices goes to saturation at about 1A/cm2 current density;and under pulsed current with low duty ratio,it grows with current density near-linearly up to 20A/cm2,and with increasing of circumstance temperture,the luminescence decreases rapidly.After analyszing the devices in heated state,it is shown that temperature-quenching,instead of field-quenching,leads to luminescence saturaiton of the devices at high current,and at last some methods of improving heat dissipation of the device are proposed briefly.关键词：a-SiC thin film light-emitting diode;temperature-quenching;temperature of junction103|107|0更新时间：2020-08-11
- 摘要：In this paper,a theoretical model based on the Grabowski's theory of twisted intramolecular charge transfer(TICT)excited state is propo-sed to deal with the formation dynamics of TICT excited state.It is shown that the TICT excited state is a.main nonradiative relaxation path of S1p singlet state:knτp=kic+kiscp+kpt.The fluorescence lifetime of 7-aminocoumarin C1F and C2F in alcohols was measured using the time-correlated single photon counting methods.And the effects of different solvent on lifetime(τf),nonradiative relaxation rate(knτ)and the formation rate of TICT excited state(kpt,)were investigated.It is found that kpt-1 of cournarin molecules depends on η/T in.the monobasic alcohols,and increases nonlinearly with η/T in polybasic alcohols.The former agrees with Debye-Stokes-Einstein's theory.And it is also found that H-bond effect among alcohol molecules and between solute and alcohol molecules is an important factor which affects the process and can not be neglected.101|67|0更新时间：2020-08-11
- 摘要：The title chelates were prepared by benzoyltrifluoroacetone with TPPO,Bipy,Phen,N(Me)4OH and Eu,Tb,Sm,Dy chlorides.They are tri-β-diketonates and tetra-β-diketonates.The fluorescence spectra of solid paosphor were determined at room temperature.The transferable intensity of energy of europium chelates in 5D0-7F2 is the strongest.The relative intensities of luminescence for EuL3Bipy and EuL3(TPPO)2 are very strong.They are 100% and 93.7% respectively.The transition is 5D4-7F5 for Tb,4C5/2-6H9/2 for Sm and 4F9/2-6H12/2 for Dy.The intensities of luminescence for the chelates of Tb,Sm and Dy are very weak,except TbL3(TPPO)2.Due to its higher stability,the fluorescence intensity of N(Me)4EuL3 in nonpolar solvent is the strongest.It is found that a minute amount of EuL3Bipy or EuL3(TPPO)2 in transparent resin will show sharp red fluorescence under the irradiation of~365nm light.115|98|3更新时间：2020-08-11
- 摘要：Emission spectra have been studied for the polymer film(PET)expo-sed to 308nm pulsed excimer laser.The emission spectra of the polymer films which have been irradiated by UV lamp are also studied.These two kinds of spectra show no difference in our experiments.It is found that the spectra belong to C2 swan systerm and CN red system.Our experiments show that the etching depth of each pulse is about 1μm when the laser intensity is 300mJ/cm2,and the threshold of etching is 50mJ/cm2.SEM photos of the irradiated surface are also given.关键词：etching effect;polymer film;intensity threshold102|95|0更新时间：2020-08-11
- 摘要：Diamine,a derivative of triphenyldiamine,was synthesized.The absorption and photoluminescent properties of the diamine thin film were investigated.Its charge conductivity was measured also.A type of organic thin film electroluminescent device with two layer structure,using diamine as hole transporting material,Alq3 as emitting material,was fabricated.It was found that when diamine was used the EL brightness of device is increased by a order of magnitude,though the electrical current passing through the device is less than half at the same applied voltage,By analysing the change of the EL spectra of the device with the laser dye DCM doped thinner layer at different possition in the emitting film,the mechanism of electroluminescence of two type devices has been studied.It is showed that the molecular excitons are generated at the interface of diamine and Alq3 layer,diffused toward the Al cathode and formed a exponential distribution in two-layer device,while in single layer device,the excitons are generated at a narrow zone in Alq3 layer,30nm apart of ITO layer,diffused in both directions and formed a peak.A luminescent model is built up and the experimental results are well explained.The diffusion length is evaluated as 21nm according to an equation derived from diffusion law.104|76|0更新时间：2020-08-11
- 摘要：In-situ Raman spectra were recorded during the process of electrochemical redox of polypyrrole.The intensities of the four Raman peaks of polypyrrole [1566cm-1(νc=c),1315cm-1(νc-c),1040cm-1(δc-H)and 986Cm-1(δring)] are very sensitive to doping,and change reversion in doping-undoping cycles.The intensities decrease drastically with doping level,and disappear at the electrode potential of about+0.1V vs.Ag/AgCl.The influence of anion size on doping was distinguished by the in-situ Raman technique.It is found that small size is in favor of doping.135|82|0更新时间：2020-08-11
- 摘要：The absorption spectrum of Na5Er(MO4)4 single crystal has been measured,and its three spectral intensity parameters have been fitted.The integral emission cross-sections of Er3+ emission transitions have been calculated.According to these the probability of emitting lasre for fluorescence lines of this crystal is discussed.97|63|2更新时间：2020-08-11
- 摘要：For the first time we indicate an unusual phenomenon in several different hosts the fluorescence line shifts of rare earth ions Eu3+ or Nd3+ under high pressure or low temperature are same,but the shifts of the transition metal ion Cr3+ are different(red shift under icreasing pressure and blue shift under decreasing temperature).110|62|0更新时间：2020-08-11
- 摘要：The porous silicon samples were prepared by anode electrochemical etching method.In this reserch,we discovered that porous silicon layer(PSL)can store charge for the first time.This characteristic of PSL shows:(1)There is a quantity of charge in PSL after anode electrochemical etching;(2)PSL possesses charge storage character similar to capacity after it was charged by DC(direct current)supply.The experiment results show n-Si sample can store charge up to 5×10-3 coulomb after charged for twenty minutes with DC 12V supply.89|69|0更新时间：2020-08-11
- 摘要：We have studied the photovoltage decay curve of porous silicon(PS)for the first time.The photovoltage decay curve is quiet different from that of single crystalline Si,the maximum of photovoltage is stronger than that of Si.The photovoltage decay curve of PS indicates that the photovoltage quickly appears after laser pulses,and then changes slowly with many small unstable peaks until a photovoltage pulse appears,the photo-voltage begins to decrease slowly only after the photovoltage pulse appears.This phenomenon is attributed to charge storage on PS surface and the charge exchanging between the interface states and crystalline Si substrate.116|54|0更新时间：2020-08-11
- 摘要：A new photovoltaic characteristic of porous silicon(PS)is reported in this paper.The PS layer was prepared by anodization of p-type Si single cryatal wafers in HF aqueous solution at current density of about 10mA/cm2.When the PS layer was irradiated by light,an intense photo-electromotive force was generated on the sample.The potential of PS layer is higher than that of substrute.The photocurrent was inereased with increasing illuminance.There was no any photoelectromotive force on a p-type Si single crystal wafer when it was irradiated with light.These facts demonstrat that the photovoltaic effect is originated in PS layer.This effect was also observed on samples formed by n-Si single crystal wafers.96|60|0更新时间：2020-08-11
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