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排序方式: 共有208条查询结果,搜索用时 46 毫秒
81.
《Organic Electronics》2014,15(6):1222-1228
In this work, we fabricated nanostructured transparent organic light-emitting diodes (TrOLEDs) using phosphorescent materials and a WO3 layer with various periods of perforation, to improve light extraction. Using these nanostructured TrOLEDs, higher external quantum efficiency (EQE) values were achieved, of 7.8% (bottom emission), and 2.0% (top emission) at 100 mA/cm2. Compared to conventional TrOLEDs, these were 28% and 33% higher for bottom and top emission, respectively. In addition, by varying the periods of the nanostructures, we found that the extraction of the trapped surface plasmon mode was mainly responsible for enhancing outcoupling efficiency. When adopting light extraction methods in TrOLEDs, one should consider the influence of the optical clarity of devices. The nanostructured TrOLEDs in this study showed good optical clarity as the total transmittance was consistent with direct transmittance. Photographs of the TrOLEDs also showed neither optical blur nor haziness. Lastly, the total transmittance of the nanostructured TrOLEDs was similar to that of a conventional TrOLED except for two points where light coupling to the surface plasmon mode and waveguide mode occurred. 相似文献
82.
A. Cortes H. Gmez R. E. Marotti G. Riveros E. A. Dalchiele 《Solar Energy Materials & Solar Cells》2004,82(1-2):21
CdS thin films were deposited by chemical bath deposition onto glass substrates from chemical bath containing cadmium sulfate, thiourea and ammonia at pH=10.5. The temperature of the bath was maintained at either 75°C or 85°C and under mill stirring. After that the samples were annealed in air at 450°C. Analysis of the as-deposited thin films by energy dispersive X-ray analysis showed that almost all samples have a stoichiometric composition. The morphology of CdS films has been investigated by atomic force microscopy. The structural properties were determined by XRD and a cubic zincblende phase was present in all of the as-grown samples. Evidence of a wurtzite phase appeared after annealing. Grain sizes between 85 and 205 Å were determined from the XRD diffraction peak broadening. The sizes increase with both bath temperature and annealing. The optical properties were studied measuring the transmittance spectra. The room-temperature bandgap energies for each sample were determined from the transmittance by two different methods: extrapolating absorption coefficient and first derivative peak position. The bandgap energy varies from 2.48 to 2.35 eV following closely the quantum confinement dependence of energy against crystallite radius. This shows that the absorption edges of these samples are determined primarily by the grain sizes. 相似文献
83.
84.
AbstractInfrared radiative properties of thermal barrier coatings have been investigated for developments of solar absorbing surface coatings. Various types of multilayer broadband optical filters were designed incorporating 7 wt-% yttria stabilised zirconia (7YSZ) and aluminium oxide (Al2O3). Electron beam physical vapour deposition method was employed to deposit 7YSZ thin films on quartz substrates to study their optical properties. The refractive index and thickness of 7YSZ films were estimated using spectroscopic ellipsometry technique, giving the index as 1·95 at 633 nm. Multilayer thermal barrier coating structures were fabricated by depositing alternate layers of 7YSZ and Al2O3 on quartz using electron beam physical vapour deposition. The spectral characteristics of multilayer 7YSZ–Al2O3 coatings were evaluated using a spectrometer in the visible and near infrared range. Preliminary results obtained from multilayer 7YSZ–Al2O3 coatings had exhibited 75% transmission over a wide band of 0·4–1·0 μm. 相似文献
85.
Jongwoon Park Yong-Young Noh Jin Woo Huh JeongIk Lee Hyeyong Chu 《Organic Electronics》2012,13(10):1956-1961
We investigate the optical and barrier properties of thin-film encapsulations (TFEs) for transparent organic light-emitting diodes (TOLEDs). To improve the barrier property of OLEDs, the number of dyads (Al2O3/polymer) and the thickness of polymer layer in the TFE structure are required to be increased. It is, however, demonstrated that a sharp dip appears in the transmittance of TFE films due to the interference of light caused by organic/inorganic multi-layered configuration, resulting in a dip in the top emission spectrum of TOLEDs. We have found that such a transmittance dip deepens when the number of dyads is large. What is worse, the number of transmittance dips and their sharpness are raised with increased thickness of the polymer layer. When the number of dyads is small, however, the effect of the polymer layer thickness on such a transmittance dip is weak. Therefore, we have addressed that the number of dyads needs to be reduced, but the thickness of the polymer layer should be increased to meet both optical and barrier properties of TOLEDs at the same time. 相似文献
86.
87.
星载大气痕量气体差分吸收光谱仪杂散光抑制 总被引:2,自引:1,他引:1
考虑杂散光对星载大气痕量气体差分吸收光谱仪测量精度的影响,设计了遮光罩和其他消杂光结构来抑制杂散光,并对杂散光进行了分析。利用TracePro软件分析了系统紫外通道1(240~315nm)的杂散光水平,确定了杂散光传输的一次、二次散射路径。根据杂散光传输路径,计算了杂散光评价指标点源透射比(PST)曲线,结果显示杂散光抑制措施效果明显,PST小于3×10-5,中心视场杂散光照度水平为5.472×10-4,最终杂散光水平达到了设计指标要求。采用截止滤光片法测量了系统的杂散光水平,结果表明:中心视场杂散光比值为8.167×10-4,和仿真结果接近,验证了仿真过程的准确性,说明设计的消杂光机构能够满足抑制系统杂散光的要求。 相似文献
88.
Snow density is one of the key properties to characterize a snow cover. We present diffuse near-infrared transmittance measurements with an integrating sphere setup in the laboratory. We analyze 8 snow samples taken from melt forms, decomposed, rounded, faceted and machine made snow. Reference measurements of specific surface area (optically equivalent grain size) and density are done by micro-computed tomography and used as input for transmittance calculations. A diffuse flux extinction model cannot be applied to simulate transmittance as our setup cannot be approximated by an infinite snow block thickness. Calculations with a more intricate radiative transfer model (DISORT) agree with our measurements within the estimated grain size and density variability for all probed natural snow types. Only our machine made snow shows a morphology which cannot be modeled by DISORT. Thus, our results show for the first time a direct experimental correlation between transmittance and snow specific surface area and density without the need for an empirical fitting parameter. We feel this to be an important step towards a possible high-resolution, quantitative optical measurement method to determine snow density in combination with an independent specific surface area measurement. 相似文献
89.
90.
Transparent and conductive Al-doped ZnO (AZO) thin films were deposited on substrates including alkali-free glass, quartz glass, Si, and SiO2 buffer layer on alkali-free glass by using radio frequency magnetron sputtering. The effects of different substrates on the structural, electrical and optical properties of the AZO films were investigated. It was found that the crystal structures were remarkably influenced by the type of the substrates due to their different thermal expansion coefficients, lattice mismatch and flatness. The AZO film (100 nm in thickness) deposited on the quartz glass exhibited the best crystallinity, followed sequentially by those deposited on the Si, the SiO2 buffer layer, and the alkali-free glass. The film deposited on the quartz glass showed the lowest resistivity of 5.14 × 10− 4 Ω cm among all the films, a carrier concentration of 1.97 × 1021 cm− 3 and a Hall mobility of 6.14 cm2/v·s. The average transmittance of this film was above 90% in the visible light spectrum range. Investigation into the thickness-dependence of the AZO films revealed that the crystallinity was improved with increasing thickness and decreasing surface roughness, accompanied with a decrease in the film resistivity. 相似文献