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181.
J.H. Selj T.T. MongstadR. Søndenå E.S. Marstein 《Solar Energy Materials & Solar Cells》2011,95(9):2576-2582
Solar modules are becoming an everyday presence in several countries. So far, the installation of such modules has been performed without esthetic concerns, typical locations being rooftops or solar power plants. Building-integrated photovoltaic (BIPV) systems represent an interesting, alternative approach for increasing the available area for electricity production and potentially for further reducing the cost of solar electricity. In BIPV, the visual impression of a solar module becomes important, including its color. The color of a solar module is determined by the color of the cells in the module, which is given by the antireflection coating (ARC). The ARC is a thin film structure that significantly increases the amount of current produced by and, hence, the efficiency of a solar cell. The deposition of silicon nitride single layer ARCs with a dark blue color is the most common process in the industry today and plasma enhanced chemical vapor deposition (PECVD) is mostly used for this purpose. However, access to efficient, but differently colored solar cells are important for the further development of BIPV. In this paper, the impact of varying the color of an ARC upon the optical characteristics and efficiency of a solar cell is investigated. The overall transmittance and reflectance of a set of differently colored single layer ARCs are compared with multilayered silicon nitride ARCs, all made using PECVD. These are again compared with porous silicon ARCs fabricated using an electrochemical process allowing for the rapid and simple manufacture of ARC structures with many tens of layers. In addition to a comparison of the optical characteristics of such solar cells, the effect of using colored ARCs on solar cell efficiency is quantified using the solar cell modeling tool PC1D. This work shows that the use of multilayer ARC structures can allow solar cells with a range of different colors throughout the visual spectrum to retain very high efficiencies. 相似文献
182.
利用Silvaco-TCAD半导体器件仿真软件,全面系统地分析了光照区域结构参数对硅NPN型红外光电晶体管光电转换特性的影响.仿真结果表明:厚度为240 nm/130 nm的SiO2/Si3 N4双层减反射膜在特征波长(λ =0.88μm)处具有最优的光吸收效果和峰值光响应度(RM);为满足器件对红外波段的有效吸收和响应,外延层厚度应选择为55 ~ 60 μm;提高外延层电阻率虽可增大集-射击穿电压(BVCEO),但较高的外延层电阻率同时会降低红外波段光谱响应度;为了获得较高的红外光谱响应度,同时抑制可见光波段的响应,光照区域基区表面浓度应选择为5×1019 cm-3,结深应选择为2.5μm. 相似文献
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185.
高瓦斯、高地应力掘进工作面顶板围岩动力现象频繁出现,严重制约了矿井安全生产。为防止煤岩动力灾害事故发生,五阳煤矿采用水力压裂技术开展掘进工作面顶板围岩卸压增透试验,以减小巷道上方应力效应、预先释放顶板瓦斯。利用瞬变电磁仪检测煤层裂隙电阻率变化以表征顶板水力压裂试验开展情况,通过对比顶板水力压裂前后工作面瓦斯浓度、煤炮响应次数及微震事件,研究顶板水力压裂技术的防灾效果。研究表明,煤层电阻率受顶板水力压裂效果影响巨大,同时压裂防灾效果明显,施工前后各项指标均有明显降低,瓦斯浓度降低40%,煤炮响应次数减小85%,微震事件减小76%。 相似文献
186.
Karl W. Koch Brooke Hathaway Carlo Kosik Williams Jaymin Amin Alexandre Mayolet Deeder Aurongzeb Joseph McDonald Shandon Hart 《Journal of the Society for Information Display》2020,28(10):801-807
Antireflection (AR) coatings can improve the viewing experience of a display, including mobile electronic devices such as smartphones, tablets, and laptops that are typically operated on battery power and protected with chemically strengthened glass. In this work, we discuss the trade‐offs between optimal user viewing experience in brightly lit environments and battery lifetime for an AR versus a non‐AR mobile display. We show that under 400–1,000 lux ambient illumination, an AR‐based display can be operated at >30% lower luminance than a non‐AR display with similar human perception of contrast based on a perceptual contrast length model, resulting in a potential improvement of >15% in device battery lifetime and a similar proportion of energy savings. 相似文献
187.
We present an approach for the optimization of thin film antireflective coatings for encapsulated planar silicon solar cells in which the variations in the incident spectra and angle of incidence (AOI) over a typical day are fully considered. Both the angular and wavelength dependences of the reflectance from the surface, absorptance within the coating, and transmittance into the device are calculated for both single‐ and double‐layer antireflection coatings with and without thin silicon oxide passivation layers. These data are then combined with spectral data as a function of time of day and internal quantum efficiency to estimate the average short‐circuit current produced by a fixed solar cell during a day. This is then used as a figure of merit for the optimization of antireflective layer thicknesses for modules placed horizontally at the equator and on a roof in the UK. Our results indicate that only modest gains in average short‐circuit current could be obtained by optimizing structures for sunrise to sunset irradiance rather than AM1·5 at normal incidence, and fabrication tolerances and uniformities are likely to be more significant. However, we believe that this overall approach to optimization will be of increasing significance for new, potentially asymmetric, antireflection schemes such as those based on subwavelength texturing or other photonic or plasmonic technologies currently under development especially when considered in combination with modules fixed at locations and directions that result in asymmetric spectral conditions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
188.
为了丰富切槽爆破增透理论,以期为指导切槽爆破增透实践提供理论依据,采用理论分析、数值模拟、相似模拟试验的方法对切槽爆破在含控制孔情况下的裂隙扩展机制进行研究。研究表明:控制孔作用下的切槽爆破在切槽根部会产生抑制区,切槽方向上的压应变峰值是切槽45°方向上的压应变峰值的2.77倍,是拉应变峰值的1.94倍;应力波传播至控制孔后反射成拉伸波,反射拉伸波和切槽尖端的集中应力产生叠加,促进切槽尖端裂隙的扩展。说明含控制孔的切槽爆破可以有效避免爆破裂隙的随机发育,对爆破裂隙有着良好的控制导向作用,可达到定向爆破煤岩体的效果。 相似文献
189.
Fabrication of Periodic Nanostructure Assemblies by Interfacial Energy Driven Colloidal Lithography
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A novel interfacial energy driven colloidal lithography technique to fabricate periodic patterns from solution‐phase is presented and the feasibility and versatility of the technique is demonstrated by fabricating periodically arranged ZnO nanowire ensembles on Si substrates. The pattern fabrication method exploits different interfaces formed by sol–gel derived ZnO seed solution on a hydrophobic Si surface covered by a monolayer of colloidal silica spheres. While the hydrophobic Si surface prevents wetting by the seed solution, the wedge shaped regions surrounding the contact point between the colloidal particles and the Si substrate trap the solution due to interfacial forces. This technique allows fabrication of uniform 2D micropatterns of ZnO seed particles on the Si substrate. A hydrothermal technique is then used to grow well‐defined periodic assemblies of ZnO nanowires. Tunability is demonstrated in the dimensions of the patterns by using silica spheres with different diameters. The experimental data show that the periodic ZnO nanowire assembly suppresses the total reflectivity of bare Si by more than a factor of 2 in the wavelength range 400–1300 nm. Finite‐difference time‐domain simulations of the wavelength‐dependent reflectivity show good qualitative agreement with the experiments. The demonstrated method is also applicable for other materials synthesized by solution chemistry. 相似文献
190.
Organic–inorganic halide perovskite solar cells are one of the most efficient photovoltaic devices, and their power conversion efficiency (PCE) continues to grow rapidly due to the optimization of device architecture and functional materials. The involved optical design has an important impact on performance by affecting the light harvesting capability. Here, demonstrated is a simple and effective strategy to boost device performance from the perspective of light management. A diffraction grating pattern into the TiO2 scaffold and antireflection layer is simultaneously introduced to construct a double grating design for perovskite solar cells. The grating pattern obtained using a commercial compact disk as the hard mold can modulate light transport by enhancing the light transmittance and, thus, light absorption in perovskite solar cells. The grating pattern‐induced light trapping can significantly increase the short‐circuit current density and PCE by 4.8% and 7.9%, respectively, on average. The present work develops a feasible method by tailoring the morphology‐related optical property to further improve the performance of perovskite solar cells. The double grating design can also generate structural color and can provide an alternative solution for fabricating colorful solar cells. 相似文献