Structuring of Macroporous Silicon for Applications as Photonic Crystals

Uniformity and high refractive index contrast make macroporous silicon an ideal two-dimensional photonic crystal, that can be tailored over a wide range of frequencies. For optical transmission measurements the porous silicon has to be structured further. Light has to be coupled in perpendicular to the pore axis and to traverse a well defined number of pore layers. For this purpose a lateral structuring technique has been developed that allows to remove the porous silicon with a precision of less than one pore lattice constant. Bars of macroporous silicon which are 100 m high, 2–200 m wide and several mm long have been prepared. These bars have been aligned with designed defect structures like linear or bent waveguides in the porous silicon. The achieved samples are well suited to investigate the optical properties of these defects with light traveling perpendicular to the pore axis.     

响应性光子晶体的研究进展

简要介绍了光子晶体的概念及各种制备方法,详细综述了响应性光子晶体的研究进展,包括:1胶体晶体水凝胶阵列;2反蛋白石结构水凝胶;3反蛋白石状光子晶体微球;4微凝胶胶体晶体;5浸润性控制的光子晶体。     

光子晶体及SiO2光子晶体的制备技术

光子晶体是一种具有光子带隙的周期性电介质结构,落在光子带隙中的光将不能传播。由于其独特的调节光子传播状态的功能,成为实现光通讯和光子计算机的基础。SiO2胶体球作为胶体光子晶体的组成基元,具有广阔的应用前景。本文介绍了光子晶体的概念、特征与应用领域,以及SiO2光子晶体的制备技术。     

基于聚合物的一维光子晶体研究进展

从一维光子晶体组装材料角度出发,总结分析了基于聚合物的有机/有机型和有机/无机杂化型一维光子晶体的结构特点、组装原理和方法、性能及应用。在有机/有机型一维光子晶体中,主要介绍了含有不同亲疏水链段的嵌段共聚物和含有可聚合双键的表面活性剂自组装形成的一维光子晶体。在有机/无机杂化型一维光子晶体中,既论述了基于聚合物、无机材料直接交替组装形成的多层膜,也讨论了基于两种无机材料组装,然后再填充柔性聚合物的一维光子晶体。通过对以上两类光子晶体材料的总结分析可知,基于聚合物材料制备的一维光子晶体可以实现多种功能,在柔性传感器、柔性光电器件、光子晶体纸、电子皮肤、3D打印等方面具有良好的应用前景。但目前基于聚合物的一维光子晶体存在组装均匀性有待提高、组装面积较小等问题,如何大规模制备均匀的功能性一维光子晶体是重要的研究方向,也是影响其实际应用的关键。     

Smart Processing Development of Photonic Crystals and Fractals

A new concept of smart processing is proposed that can produce advanced materials and components by finely controlling processing energy and engineering structures. New functional components of 3D photonic crystals and fractals are demonstrated, which are constructed of dielectric ceramics and a polymer using a CAD/CAM stereolithography system. By modifying the structure of diamond-like photonic crystals using free-form fabrication, electromagnetic waves can be controlled, opening the way for new applications in communication and sensing technology. The photonic fractal, a new material that can strongly localize electromagnetic waves without reflection and transmission, will also lead to new applications in the energy and medical fields.     

电阻率对N型单晶硅电池电性能影响的研究

近年来,P型太阳电池商业化生产效率已趋于稳定,N型太阳电池逐渐走向产业化.基于N+ Np+型铝背结单晶硅太阳电池,研究了电阻率为1 ～5.5 Ω·cm的N型硅衬底材料经过相同工艺后电池性能的差别,可以有效的节省成本.通过选用不同电阻率的N型硅片,经过相同的工艺制备N型单晶硅太阳电池,采用QSSPC、四探针、ECV、恒光源Ⅰ-Ⅴ测试系统对电池的少子寿命、方块电阻、磷元素分布、电性能进行测量.实验结果表明:虽然电池的少子寿命随电阻率的升高而升高,但是在方块电阻、磷元素分布、开路电压Voc、短路电流Isc、填充因子FF、转换效率Eff等方面不同电阻率的电池并无明显差异.     

可调制光子晶体材料的研究进展和展望

可调制光子晶体材料是一类通过调节自身光子带隙结构对外场刺激做出响应的先进光子材料,它比传统的非调制光子晶体表现出更加优异的性能,近年来已成为光子晶体研究中的一个重要领域。本文简单介绍了近年来可调制光子晶体材料的发展状况,阐述了其调制机理及存在的问题,同时对未来光子晶体材料的发展提出了展望。     

A Silicon Nanocrystal Schottky Junction Solar Cell produced from Colloidal Silicon Nanocrystals

Solution-processed semiconductors are seen as a promising route to reducing the cost of the photovoltaic device manufacture. We are reporting a single-layer Schottky photovoltaic device that was fabricated by spin-coating intrinsic silicon nanocrystals (Si NCs) from colloidal suspension. The thin-film formation process was based on Si NCs without any ligand attachment, exchange, or removal reactions. The Schottky junction device showed a photovoltaic response with a power conversion efficiency of 0.02%, a fill factor of 0.26, short circuit-current density of 0.148 mA/cm², and open-circuit voltage of 0.51 V.     

Silicon Solar Cell with Nanoporous Structure Formed on a Textured Surface

A nanoporous silicon (Si) surface was formed on monocrystalline silicon solar cells by electrochemical etching. The galvanostatic mode was applied to conventional n–p–p⁺ solar cells, which were fabricated by pyramidal texturing, phosphorous diffusion, screen-printing, rapid thermal firing, and laser isolation (effective area of 144.7 cm²). Without an additional antireflection layer such as SiN _x , the anodic reaction of the Si wafer could provide uniform porous layers on a pyramidal surface (111) with relatively low reflectance, and it would improve the photovoltaic performance.     

New Type Anode for Calcium Ion Batteries Based on Silicon Carbide Monolayer

Silicon - A theoretical research study was conducted into the possibility of using a two-dimensional graphene-like material silicon carbide nano-sheet (2D-SiCNS) as an anode in rechargeable Ca-ion...     

硅太阳能电池背银浆料所用银粉的研究

本论文重点研究了背银浆料中所用银粉的粒径、形貌对浆料性能的影响。结果表明,背面银浆中所用的银粉对于保障电性能、提高附着力和焊接力起着关键的作用。在低固含量的情况下,使用微片状银粉制备的浆料,所得电极膜致密光滑,电性能优良,并且附着力和焊接性能好。     

Refining Silicon for Solar Cell Application by Copper Alloying

Introduction  

One major problem in the photovoltaic industry is the high price of refined solar grade silicon. In this research, a new method for refining metallurgical grade silicon to solar grade silicon is investigated.     

Photonic Delay Lines Based on Silicon Coupled Resonator Optical Waveguide Structures

Silicon - We propose a Coupled Resonator Optical Waveguide Structure based on silicon microring resonators. The proposed structure is designed on Silicon on Insulator platform so as to scale down...     

Silicon Based One-Dimensional Photonic Crystal as a TM-Mode Filter

The effect of temperature and angle of incidence on the transmission spectra of a one dimensional photonic crystal for TE and TM polarizations has been studied. For a range of angle of incidence from 0° to 60°, the proposed structure works as an omni-directional reflector. For other angles of incidence more than 60°, the structure works as a selective TM-polarization filter i.e. a filter which completely blocks TE-polarized waves but allows certain frequencies of TM-polarized waves. At an angle of incidence of 89°, the structure works as a multi channel optical filter without introducing any defect in the geometry. Also, this multi-channel filter can work as a tunable filter by varying the temperature of the structure and the number of layers in the geometry. Only for two bi-layers the proposed structure works as a single channel filter. Therefore, such types of structure are easier to fabricate and may be cost effective as compared to defect one-dimensional photonic crystals.     

一种新型柔性硅太阳能电池装置的设计和搭建

利用微分几何思想,将面积较大的太阳能电池片用导线分别进行先串联后并联、先并联后串联两种方式连接,以柔性材料填充每个太阳能电池片之间的空隙来制备柔性太阳能电池装置。实验结果表明,以这种微分思想搭建的硅太阳能发电装置具有良好的柔性和较高的输出功率,并且以先串联后并联电路的最大输出功率略优于以先并联后串联电路。     

Evaporation-Assisted Formation of Three-Dimensional Photonic Crystals

The process of evaporation-assisted formation of three-dimensional photonic crystals was studied. The photonic crystals were fabricated by stacking uniform-sized silica spheres into regularly arranged structure with solvent evaporation and sedimentation. Effects of important process parameters, including type of solvent (water and ethanol), system temperature (40° and 60°C), and material for sedimentation cell (quartz, polymethyl methacrylate, and Teflon), on structure regularity of the resulting photonic crystal were investigated. The structure regularity was evaluated with scanning electron microscope graphs and stop band depth achieved in optical absorption spectra. As revealed from the experimental results, photonic crystals of better quality were obtained by using suspending solvents of higher surface tension (water), lower system temperatures (40°C), and sedimentation cell materials of higher critical surface tension of wetting (quartz).     

Efficient Ice-Bath Texturing Route for Multi-Crystalline Silicon Solar Cell Application

Silicon - To minimize reflection from the flat surface, the multicrystalline silicon (mc-silicon) wafers were textured by low-temperature acid etching technique, which was optimized etching...     

晶硅太阳电池上表面减反射膜的效果评价与分析

本文首先利用Silvaco-TCAD半导体器件仿真软件建立基于优化减反射膜结构的二维晶硅太阳电池结构.然后利用传递矩阵法(TMM),优化设计由多种常见介质膜材料组成的减反射膜结构.最后详细分析了SiO2/Si3N4和MgFJZnS双层减反射膜对太阳电池性能的影响.结果表明:在400 ～ 750 nm波长范围内,MgF2/ZnS减反射膜光反射损耗最小.在850～1200nm波长范围内,SiO2/Si3N4减反射膜光反射损耗最小.光反射损耗越小,太阳电池量子效率和转换效率越高.减反射膜的钝化效果对晶硅电池短波段(λ＜550 nm)光谱响应影响较大.通过光吸收效果和钝化效果对减反射膜性能进行综合评价,SiO2/Si3N4减反射膜优于MgF2/ZnS减反膜,更有利于晶硅太阳电池转换效率的提高.     

An Investigation on a Crystalline-Silicon Solar Cell with Black Silicon Layer at the Rear

Crystalline-Si (c-Si) solar cell with black Si (b-Si) layer at the rear was studied in order to develop c-Si solar cell with sub-band gap photovoltaic response. The b-Si was made by chemical etching. The c-Si solar cell with b-Si at the rear was found to perform far better than that of similar structure but with no b-Si at the rear, with the efficiency being increased relatively by 27.7%. This finding was interesting as b-Si had a large specific surface area, which could cause high surface recombination and degradation of solar cell performance. A graded band gap was found to form at the rear of the c-Si solar cell with b-Si layer at the rear. This graded band gap tended to expel free electrons away from the rear, thus reducing the probability of electron-hole recombination at b-Si and improving the performance of c-Si solar cell.     

晶体硅太阳能电池正面银导电浆料的研究进展

太阳能电池银浆是制造太阳能电池的主要原材料,太阳能电池银浆制造技术是高效低成本太阳能电池的关键技术。本文简介了太阳能电池结构,从太阳能电池导电银浆料的作用和性能要求出发,阐述了银浆料中各个组分对导电性能的影响、印刷适应性与导电性能的关系,并分析了国内外银浆料的现状与差异,指出了太阳能银浆料的未来发展趋势。