Solid organic UV filter for solar blind detection

The dye of 2, 7-dimethyl-3, 6-diazacyclohepta-1, 6-diene perchlorate (dye 1) and chlorination of 2, 7-dimethyl-3, 6-diazacyclohepta-1, 6-diene perchlorate (dye 2) were prepared and characterized. The dye 2 molecules were introduced into the polyvinyl alcohol (PVA) films to produce solid ultraviolet (UV) filters. UV spectroscopy measurements were carried out to investigate the optical properties of UV filters. The UV filter exhibited high transmittance within solar blind spectral region (240–280 nm) and a strong absorption band occurred between 300 and 375 nm. The detection experiment results of corona discharge show that the UV filter can be used for solar blind detection.     

近紫外冷反射镜的镀制研究

为充分利用紫外光源系统中所需要的有用的紫外光,同时减少红外光照射,根据常用紫外光源的发光特性、能量曲线分析,通过真空镀膜技术,在玻璃基片表面镀制多层硬质光学薄膜,制备出了对中紫外光谱区域的反射率高于90%,同时可见及红外区域的平均透过率在85%以上的近紫外冷反射镜。     

Preparation and characterization of hollow silica nanocomposite functionalized with UV absorbable molybdenum cluster

The nanoparticle-based material technology has recently opened a new heat shielding material generation for window applications such as aerogel, vacuum insulation panel or nanospace materials. Aiming to prepare a nanospace-based heat insulation material functionalized with an ultraviolet (UV) absorbent, the Mo₆ cluster-deposited hollow silica nanoparticles (HSNs) were prepared by the vacuum impregnation process (VIP). The pore channels of the hollow silica wall filled with the Cs₂[Mo₆Iⁱ₈(OCOC₂F₅)^a₆] octahedral cluster (CMIF) were confirmed by an HR-TEM coupled EDX device, ICP-OES and BET analysis. The retention of the octahedral structure or the typical optical property of the Mo₆ cluster in the pores of the HSNs was demonstrated by ultraviolet (UV) light absorption and photoluminescence spectroscopes even though the powders were heated to 200 °C. The multi-functional CMIF@HSNs nanocomposite could adsorb the UV rays under 400 nm and scatter the NIR light through the pores of the silica wall in order to reduce the heat passing a window. For this purpose, the film preparation based on the CMIF@HSNs nanocomposite was performed by dip coating in the commercially available top coat suspension (TCS) on soda lime glass. Excellent mechanical and optical properties of the CMIF@HSNs-based thin film were visibly obtained with a relative transmittance. This study suggests a potential insulation material prepared by a high efficiency and simple method for reducing the air temperature in buildings.     

UV电泳光成像抗蚀剂的制备及性能

合成了水可分散阳离子型丙烯酸酯光敏聚合物(UPDHES),以其为主体树脂制得了阴极光敏电泳涂料乳液,并以铜箔为阴极进行电泳成膜、闪蒸、曝光、显影成像.研究了电泳过程中电流密度的变化对涂膜的影响,并对电泳涂膜进行了扫描电镜表征;考察了光敏树脂双键含量对其光固化动力学及性能的影响;最后对光成像抗蚀荆的分辨率进行了测试.结果...     

水性UV固化涂料用多羟甲基苯酚丙烯酸酯的合成

以多羟甲基苯酚钠和丙烯酰氯为原料,合成了适用于水性UV固化涂料的多羟甲基苯酚丙烯酸酯,通过红外光谱表征了产物的化学结构。探讨了物料比、反应温度、反应时间和催化剂用量等因素对产物产率的影响,结果表明:当n(多羟甲基苯酚钠)∶n(丙烯酰氯)=1∶2、反应温度为0～-5℃、反应时间为2.5h、催化剂四丁基溴化铵用量为0.04%(占物料质量比)时,最有利于产物的合成;多羟甲基苯酚丙烯酸酯的水溶性及涂膜性能,也能较好地满足水性UV固化涂料的应用。     

Hydrophobic organic coating based water--solid TENG for water-flow energy collection and self-powered cathodic protection

Water–solid triboelectric nanogenerators (TENGs), as new energy collection devices, have attracted increasing attention in ocean energy harvesting and self-powered sensing. Polyacrylic acid (PAA) coating, usually used on the surface of marine equipment, has the property of anti-aging and anti-wear but limits triboelectrical output when used with TENGs. In this paper, polyacrylic acid coating was modified with fluorinated polyacrylate resin (F-PAA) to increase its triboelectrical output, by 6 times, and also to increase its anti-corrosion property. In addition, the corrosion resistance property can be further enhanced by cathodic protection using the electrical output generated by the water-flow triboelectrical energy transfer process. Given their easy fabrication, water-flow energy harvesting, and corrosion resistance, PAA/F-PAA coating-based TENGs have promising applications in river and ocean energy collection and corrosion protection.     

紫外光固化手机涂料附着力和耐磨性的研究

介绍了紫外光固化的概念,讨论了预聚物、活性稀释剂以及添加剂对紫外光固化手机涂料附着力和耐磨性的影响。     

涂料用纳米氧化锌/聚醋酸乙烯酯的制备及抗紫外性能

ZnO抗老化性能优良,聚醋酸乙烯酯(PVAc)热塑性好,由两者制成的复合材料具有优异的抗紫外性能,用于涂料可以提高抗老化性能.以ZnSO4和尿素为原料,用水解法制得纳米ZnO溶胶,将ZnO溶胶分散于PVAc-丙酮溶液中,制得无色透明的纳米ZnO/PVAc复合溶胶,再将两者合成无色透明的ZnO/PVAc复合膜.结果表明:ZnO在PVAc中分布均匀,形态一致;ZnO含量低于2.0%o时,ZnO/PVAc中纳米颗粒粒径在20～30 nm范围内,平均密度为27.4 nm,体积平均为27.8 nm,数均25.4 nm;与纯PVAc溶液相比,最大吸收峰蓝移了13.2 nm;复合材料中ZnO含量仅0.65%o时,吸光度增大近1倍,且随材料中ZnO含量的增加而增大.     

Comprehensive characterization of hydride VPE grown GaN layers and templates

GaN community has recently recognized that it is imperative that the extended, and point defects in GaN and related materials, and the mechanisms for their formation are understood. This is a first and an important step, which must be followed by defect reduction before full implementation of this material and its allied binaries/ternaries in devices. This review is based on a recent concerted effort to establish benchmarks as far as defects are concerned, and identify the basic issues involved. Samples were analyzed for extended defects by TEM and chemical etches, for polarity by electric force microscopy and convergent beam electron diffraction (CBED), for point defects by DLTS, for optical quality and deep defects by photoluminescence (PL), for vacancies by positron annihilation, for donor and acceptor like states within the gap by ODMR and EPR, and for carrier transport targeted for defects and impurities by variable temperature and magnetic field-dependent Hall measurements.Hydride VPE samples grown at Lincoln Laboratories with 1.5, 5.5 and 55 μm thicknesses were investigated for defects by TEM, and their polarity was found to be Ga-polarity, as expected, by CBDE combined with simulations. The density of misfit dislocations at the substrate/EPI interface was determined to be on the order of 10¹³ cm⁻² based on high-resolution electron microscopy images. The threading dislocation density decreased gradually with distance from the interface, reaching a value of about 10⁸ cm⁻² at the surface of a 55 μm film. A 200 μm thick laser separated and free-standing HVPE grown GaN template grown at Samsung was also characterized similarly. The free surface and substrate sides were confirmed to be Ga- and N-polarity, respectively. The density of dislocations near the N-face was determined to be, in order, (3±1)×10⁷ and (4±1)×10⁷ by cross-sectional TEM and plan-view TEM, respectively. Identical observations on the Ga-face revealed the defect concentration to be less than 1×10⁷ cm⁻² by plan-view TEM and 5×10⁵ cm⁻² by cross-sectional TEM.Defects in a 10 μm thick GaN layer grown by HVPE at Lincoln Laboratory have been investigated by photo electrochemical (PEC) etching, and by wet etching in hot H₃PO₄ acid and molten KOH. Threading vertical wires (i.e. whiskers) and hexagonal-shaped etch pits are formed on the etched sample surfaces by PEC and wet etching, respectively. Using atomic force microscopy, one finds the density of “whisker-like” features to be 2×10⁹ cm⁻², the same value found for the etch-pit density on samples etched with both H₃PO₄ and molten KOH. Values agree well with TEM results.A free standing GaN template has been characterized for its structural and optical properties using X-ray diffraction, defect delineation etch followed by imaging with atomic force microscopy (AFM). The Ga-face and the N-face of the c-plane GaN exhibited a wide variation in terms of the defect density. The defect concentrations on Ga- and N-faces were about 5×10⁵ cm⁻² for the former and about 1×10⁷ cm⁻² for the latter, again in good agreement with TEM results mentioned above.High resolution X-ray rocking curves (omega scans) were measured. The [0 0 2] symmetric and [1 0 4] asymmetric peaks in 10 μm thick HVPE films had FWHM values between 5.8 and 7.9 arcmin, and 3.9 and 5.2 arcmin, respectively. The Samsung template investigated had wide diffraction peaks (20.6 and 24 arcmin for [0 0 2] and [1 0 4] diffractions, respectively) on the Ga-face, similar for the N-face, when a 2 mm slit size was used. When the slit size was reduced to 0.02 mm, the Ga- and N-face [0 0 2] peaks reduced to 69 and 160 arcsec. A bowing radius of 1.2 m was calculated to account for increased broadening with wider slits.In the HVPE layer studied, SIMS investigations indicate that both O and Si concentrations drop rapidly away from the surface into the sample — mainly due in part to the artifact of the technique and in part due to condensates on the surface of the sample, down to about 10¹⁷ cm⁻³ for Si and high 10¹⁶ cm⁻³ for O. The Ga-face profile in the Samsung template indicated levels below mid-10¹⁶ cm⁻³ for all three of the impurities. The picture is different for the N-side, however, as it was juxtaposed to the substrate during growth and was mechanically polished after laser separation. The impurity concentration on this face, depending on the species, is some 1–3 orders of magnitude higher than the case for the Ga-face.Transport properties as a function of the layer thickness, ranging from about 1 to 68 μm, while all the other parameters being the same, as they evolve from the sapphire/GaN interface and up were determined in epitaxial layers. A strong dependence on distance from the interface was observed with the averaged mobility figures increasing from 190 cm²/V s in the 5 μm film to 740 cm²/V s in the 68 μm film. The preliminary differential Hall measurements indicate that the mobility at the surface of the thick layer is about 1200 cm²/V s. Electron mobilities in free-standing template were 1425 cm²/V s at T=273 K and 7385 cm²/V s at T=48.2 K. By using the most recent unscreened acoustic deformation potential and allowing only the acceptor concentration to vary (2.4×10¹⁵ cm⁻³ for the best fit), one obtains an excellent fit to the measured mobility in the temperature range of 30–273 K by using an iterative BTE method. In addition, an excellent fit for the temperature-dependent electron concentration was also obtained utilizing the acceptor concentration determined from the fit to the Hall data, and the charge balance equation. This led to a donor concentration of 1.6×10¹⁶ cm⁻³, and activation energy of 26 meV, the latter being the highest reported in the literature for GaN.In the free-standing template, the Γ₅ and Γ₆ free excitons were identified from emission measurements by utilizing polarization geometries where the E field is perpendicular to the c-axis, favoring the Γ₅ exciton, and E field parallel to the c-axis (incident beam from the edge of the wafer) favoring the Γ₆ exciton. Focusing on the defect region of the PL spectrum, the N-face of the sample exhibited the usual yellow line. However, the Ga-face exhibited a broad band encompassing both yellow and green bands. The yellow luminescence in the free-standing template is weak and can be easily saturated. In contrast, the green luminescence is dominant and is attributed to the isolated defect involving gallium vacancy, whereas the yellow luminescence is related to the same defect bound to dislocation or surface-bound structural defect.Deep centers have been characterized by DLTS in HVPE-grown GaN epilayers of different thickness and dislocation densities, and templates. The main deep centers, such as A₁, B, and D, show higher concentrations in thinner samples, which suggests a correlation to the high dislocation densities. Based on the anti-correlation between A₁ and B, which is observed in thin HVPE-GaN layers, the defect B was tentatively attributed to N_Ga. Centers A₁ and E₁ found in thin HVPE-GaN are very similar to centers A₂ and E induced by electron-irradiation, indicating their point-defect nature. Centers A, C, and D are not affected by 1 MeV electron-irradiation, thus ruling out the possibility of these centers being identical to any EI-induced centers; however, their nature remains unknown. As the layer thickness decreases, an increase of deep centers, both in species and concentrations, was clearly observed, which is believed to be closely associated with the significant increase of threading dislocations as revealed by TEM. Based on a comparison with EI-induced centers and an observation of anti-correlation, A₁ is tentatively assigned to N_I, and B to N_Ga. The template exhibited a new trap B′, with parameters E_T=0.53 eV and σ_T=1.5×10⁻¹⁵ cm² on the Ga-face, in addition to the four traps commonly observed in various epitaxial GaN layers. For the N-face, an N vacancy-related trap E₁, with E_T=0.18 eV and σ_T=4×10⁻¹⁷ cm², was observed. On the other hand, the Ga-face sample contained trap C, with E_T=0.35 eV and σ_T=1.6×10⁻¹⁵ cm². This trap may be related to surface damage caused by the RIE process employed.Electron beam and optical depth-profiling of thick (5.5–68 μm) n-type HVPE-GaN samples have been carried out using electron beam-induced current (EBIC) and micro-PL to determine the minority carrier diffusion length, L, and minority carrier lifetime. The minority carrier diffusion length increased linearly from 0.25 μm, at a distance of about 5 μm from the GaN/sapphire interface, to 0.63 μm at the GaN surface for a 36 μm thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. These observations in PL intensity and minority carrier diffusion length have been attributed to a reduced carrier mobility and lifetime at the interface and to scattering at threading dislocations.Positron annihilation experiments have been conducted in HVPE films with varying thicknesses from 1 to 68 μm. Mg-doped samples and bulk GaN platelets have also been investigated and the behavior of positron annihilation in Mg-doped samples established. Unlike the Mg-doped samples, the positron lifetime in the HVPE samples increased with decreasing lattice temperature. This was interpreted as acceptors in these n-type samples being due to Ga vacancies as opposed to relatively shallow acceptor impurities. The similarities in the behavior of these samples and those investigated previously where the III/V ratio was changed also lend support to the Ga vacancy argument. Previous investigations established that as the III/V is lowered by increasing the ammonia flow during the growth, the Ga vacancy concentration increased. Using Mg-doped samples as a standard, the vacancy concentration was determined to be about 10¹⁷ cm⁻³ near the surface for the layer with a thickness greater than 30 μm. Assuming that the growth parameters in the set of layers with varying thicknesses that were investigated are the same, the Ga vacancy concentration increases to mid-10¹⁹ cm⁻³ near the interface. Since the interfacial region is n-type and highly conductive, this region must also contain even larger concentrations of O and/or N vacancies which lead to n-type material. SIMS results already indicate mid-10¹⁹ cm⁻³ levels of O being present in this region. This has been attributed to O out-diffusion from sapphire as previously reported.FTIR, ODMR and EPR measurements have been performed in GaN layers and templates. In FTIR measurements, two absorption bands corresponding to binding energies of 30.9 (Si) and 33.9 meV were found. Splitting of the binding energies with magnetic field is consistent with an effective mass of 0.22m₀. Angular rotation studies were performed with the magnetic field oriented perpendicular and parallel to the c-axis to provide symmetry information. The ODMR on the 2.2 eV peak in a 5–10 μm thick GaN layer, the notorious yellow emission, showed signatures of shallow donor (effective mass like) and deep defect centers with g-values of 1.95 and 1.99, respectively. The 3.27 eV peak with resolved LO phonon replicas, which is the blue peak observed in many GaN films grown by a variety of methods, is attributed to transitions involving shallow acceptors with g2.1 and g2.0. ODMR on the 2.4 eV “green” PL band in the free-standing template also revealed evidence for shallow donors with a g-value of 1.95 and other deeper centers. The larger line width of the shallow donor signal from the template, relative to that found for the epitaxial layers, is indicative of a lower concentration of this center, which leads to an increased hyperfine interaction. EPR studies confirmed the notable difference between the epilayers and the template, particularly the larger line widths in the template due to the lower concentration of shallow donors. Specifically, the free-standing sample has about 6×10¹⁵ cm⁻³ uncompensated donors while the epilayers have a concentration about a factor of four higher.Calculations indicate that incorporation of Si has a negligible effect on the lattice constant, but O and Mg can lead to an observable expansion of the lattice. Since values of the GaN lattice constant have often been based on bulk crystals that are now known to contain large concentrations of oxygen, the “true” GaN lattice constant is actually smaller than what has been measured for such crystals. Boron is an unintentional impurity that can be introduced during MBE growth. There has been speculation about whether B might act as an acceptor in GaN; this would require it to be incorporated on the nitrogen site. Computations indicate that incorporating B on the N site is energetically unfavorable. Even if it did incorporate there, it would act as a deep, rather than a shallow acceptor. Formation energies of H in AlN and GaN have also been calculated. The behavior of H in AlN is very similar to GaN: H⁺ dominates in p-type, H⁻ in n-type. Surprisingly, H in InN behaves exclusively as a donor, i.e. it is not amphoteric as in GaN and AlN, but actually contributes to the n-type conductivity of the material.Scanning thermal microscopy (SThM) has been applied to measure the local thermal conductivity of epitaxial GaN as it is affected to a large extent by phonon scattering, and a closer to the true value of this parameter can be obtained by a local measurement in areas of lower defect concentration such as those found in the wing regions of lateral epitaxially grown GaN. The method relies on a thermo-resistive tip forming one quadrant of a Winston bridge. The bridge is balanced with the tip heated followed by bringing the tip in contact with the sample under test which cools down due to thermal dissipation. However, the feedback circuit attempts to keep the thermo-resistance and thus the tip temperature the same. The square of the feedback voltage necessary for this is proportional to the thermal conductivity. Accurate values can be obtained with calibration using known substrates such as GaSb, GaAs, InP, Si and Al metal. Using SThM, thermal conductivity, κ, values of 2.0–2.1 W/cm K in the wing regions of lateral epitaxially grown GaN, 1.70–1.75 W/cm K in HVPE grown GaN, and 3.0–3.3 W/cm K for free-standing AlN have been measured.     

光固化聚氨酯-丙烯酸酯乳液的制备及对纸张的增强作用

以异佛尔酮二异氰酸酯(IPDI)、聚己内酯二元醇(PCL1000)、二羟甲基丁酸(DMBA)、季戊四醇三丙烯酸酯(PETA)和丙酮等为原料合成了水性光固化聚氨酯-丙烯酸酯复合乳液,并利用该乳液对纸张进行表面施胶。通过傅立叶红外光谱(FT-IR)和光散射对乳液的结构进行了分析;研究了n(NCO)/n(OH)比值(R值)对乳液和涂膜耐水性和力学性能的影响,紫外光(UV)固化前后对纸张物理性能的影响。结果表明,当n(NCO)/n(OH)=1.6,m(PETA)=12.6%时,乳液具有良好的稳定性,涂膜呈现良好的耐水性和力学强度,吸水率降至3.66%;UV固化后纸张湿强度提高41.65%,纸张环压指数达到5.25N.m/g。     

均匀分散纳米二氧化钛的制备及其紫外线屏蔽性能

以TiCl4、三乙醇胺为原料配位形成可溶性配合物，将此配合物先驱液滴加到氨水中，得到锐钛矿型二氧化钛超细粒子溶胶。研究了先驱液的加入量对二氧化钛纳米粒子的粒径及紫外线透过率的影响。将丙烯酸树脂乳液加入到均匀分散的纳米二氧化钛粒子溶胶中，通过原位聚合的方法获得了纳米TiO2高度分散的丙烯酸树脂复合薄膜。结合纯丙烯酸树脂薄膜的紫外线透过率曲线分析了TiO2的紫外线屏蔽性能。该分散均匀的锐钛矿型TiO2对紫外线具有十分优异的屏蔽作用。     

Simulation of the organic thin film thickness distribution for multi-source thermal evaporation process

A model of multi-source thermal evaporation process was proposed to achieve higher deposition rate and uniformity of organic thin film. In this model, several point type sources were uniformly distributed around a circle and evaporated simultaneously to form a surface-like source. Based on the Monte Carlo method, the evaporation process was simulated, and the effect of the number of point type sources, circle radius and source-substrate distance on the uniformity was analyzed. Based on the method proposed in this paper, the uniformity of the thickness in the organic layer was successfully controlled in 5%.     

UV胶油墨的制备及其触变性的研究

制备了UV胶印油墨样品,探讨了油墨样品的触变性.实验结果表明:UV胶印油墨具有触变性,油墨触变性的评价结果与测试模式有关.相同最大切变速率下,切变速率变化时间长触变环面积小;相同切变速率变化时间下,最大切变速率越小触变环面积越大.     

Deposition of TiO2 nano-particles on wood surfaces for UV and moisture protection

Deposition of TiO₂ nanoparticles on wood surface was realised to improve the wood stability against ultraviolet (UV) light and moisture degradation. Photocatalytic activity of TiO₂ nanoparticles was utilised for protection of the wood surface. TiO₂ nano-particles were achieved by a sol–gel deposition method using EtOH/TiCl4 solution. Dip-coating process and subsequent annealing were used to realise nano-particles on wood surface. This method of deposition was utilised for the conformal covering of the wood structure as demonstrated by morphological investigation of the prepared samples by field emission scanning electron microscopy. Colour change measurements and Fourier transform infrared spectroscopy were used to analyse the lignin and carbonyl degradation of uncoated and coated wood during the UV exposure. Moisture protection of the coated wood was investigated by measuring the contact angle of the distilled water and wood surface. The measurements showed the UV and moisture protection of the TiO₂ layer.     

Scratch resistance analysis of coatings on glass and polycarbonate

Optical coatings are nowadays broadly used in automotive and architectural glazings, displays, etc. When applied to the outside of laminated glass panels or on single glass sheets the coatings are subject to abrasive processes like cleaning and dusty or sandy circumstances. A high mechanical stability is therefore required under various environmental loads in life cycle. In this work, scratch tests have been carried out for antimony doped tin oxide film (SnO₂:Sb) on glass and silicon oxide film (SiO₂) on polycarbonate to analyze the impact of film thickness on the scratch resistance. In addition to that, the taber test is used for the analysis of SiO₂ on polycarbonate. Simulations of the experimental set-up based on a finite element model are developed in order to investigate the elasto-plastic behaviour of the coating and substrate.     

光固化硅橡胶胶粘剂的研制

采用聚氨酯丙烯酸酯制备了光固化胶粘剂并对硅橡胶进行了粘接,讨论了光引发剂和活性稀释剂含量对胶粘剂性能的影响,利用红外光谱仪和扫描电镜对胶粘剂进行表征,得到了一种具有优良光固化性能和剪切强度的光固化硅橡胶胶粘剂.     

Outgassing characteristics of a polycarbonate core material for vacuum insulation panels

Performance deterioration with time is one of the most important issues in a vacuum insulation panel (VIP), which is mostly due to the inner gas pressure rise. Outgassing from the interior of core materials is the major gas source when the core material is a polymer. Outgassing characteristics of a polycarbonate as the VIP’s core material are examined theoretically and experimentally. To measure the outgassing rate, specific outgassing tests are carried out using a pressure rise method. Diffusive outgassing mechanism is discussed based on the Fick’s law. As the result, the total amount of dissolved gas and the diffusion coefficients of various gases in the polycarbonate are obtained by using the measured outgassing rate. Temperature dependence of the diffusion coefficient of nitrogen is also examined. It is shown that the outgassing rate of polymer core materials can be significantly reduced to a negligible level by a baking pre-treatment in vacuum and/or by a metal coating on the polymer surface.     

高量子效率碲化铯紫外日盲阴极研制

碲化铯(Cs2Te)阴极是紫外探测器的重要组成部分,其研究的时间较早,在某些紫外探测领域得到了良好应用。但是,同时具有高量子效率及良好日盲特性的阴极制备工艺还需要进一步探索。本文采用电子束蒸发镀膜在石英窗上制备金属Ni膜作为Cs2Te阴极的导电基底,用四探针测试仪、高阻计和分光光度计研究了薄膜的方块电阻和透过率关系。在超高真空系统中进行Cs2Te阴极制备,研究Te膜厚度对阴极量子效率的影响关系。用X光能量色散谱分析Cs2Te光电阴极的组分,研究Cs量与阴极日盲特性的影响关系。结果表明,最佳Ni膜厚度为1.0 nm,其电阻为107Ω/□左右,其紫外波段透过率高达80%;Cs2Te阴极的Te膜厚度为2.0nm时,光电阴极量子效率达12%;当Cs2Te阴极中Cs过量,其波长响应向长波方向延伸,Cs欠量,阴极量子效率降低。     

新型复合双层光学增透膜的制备与性能

采用液面下降法在载玻片上制备了T iO2-S iO2/S t-MM A共聚物复合双层光学增透膜。考察了成膜材料组成对内外膜层折射率的影响规律,研究了紫外光辐照处理对内层无机膜厚度和折射率的影响,用紫外-可见分光光度计测试了增透膜的透过率。实验结果表明各膜层折射率随其组成比的变化而线性变化,内层膜和外层膜的折射率可分别在1.45~2.0和1.49~1.60之间连续可调。制备的双层光学增透膜在420 nm~600 nm光谱范围的透过率有很大提高,最高透过率达到99.5%,最高透过波长的位置可通过膜层厚度调整。