Nanotextured multicrystalline Al‐BSF solar cells reaching 18% conversion efficiency using industrially viable solar cell processes

We report recent achievements in adapting industrially used solar cell processes on nanotextured surfaces. Nanostructures were etched into c‐Si surfaces by dry exothermic plasma‐less reaction of F species with Si in atmospheric pressure conditions and then modified using a short post‐etching process. Nanotextured multicrystalline wafers are used to prepare Al‐BSF solar cells using industrially feasible solar cell proc‐ essing steps. In comparison to the reference acidic textured solar cells, the nanostructured cells showed gain in short circuit current (J_sc) of up to 0.8 mA/cm² and absolute gain in conversion efficiency of up to 0.3%. The best nanotextured solar cell was independently certified to reach the conversion efficiency of 18.0%. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Selective etching of ZnTe in HF:H2O2:H2O solution: Interpretation of extended defect‐related etch figures

HF:H₂O₂:H₂O solution (40%wt.HF: 30wt.%H₂O₂: H₂O, 3:2:1 by volume) was used to reveal extended defects (line, face and volume defects) in bulk ZnTe crystals grown from Te solution. The etch patterns were analyzed based on their size, shape and distribution. The etch figures, both in the shape of pits and hillocks with high resolution, show forms controlled by the symmetries of the respective faces were produced. Two different sizes of pits were observed, the larger‐size pits correspond to dislocations penetrating the surface, however, the smaller‐size texture pits are produced on the defect‐free region, which serve as standard pits on respect faces. The face defects, such as grain boundaries, sub‐grain boundaries, dislocation walls, twins and stacking faults, can be all displayed clearly. Another essential feature of the etchant is that, it can effectively dissolve Te‐rich phase (Te inclusion/precipitates), which makes it promising to reveal the shape of this volume defect.     

Effects of acid etching on the structure of PtNi catalyst and total exposed active sites

The integration technology of hydrogen preparation–hydrogen storage not only can utilize hydrogen energy efficiently but also can improve the selectivity of the electrode maximally. In the present work, the structure and composition of the PtNi catalyst was characterized by X-ray diffraction (XRD); and its electrochemical properties, morphology, and surface binding energy were analyzed by cyclic voltammetry (CV) and linear scanning voltammetry (LSV), scanning electron microscopy equipped with energy-dispersive spectrometry (SEM-EDS), and X-ray photoelectron spectroscopy (XPS), respectively. The effects of different acid etching treatments (e.g., etching time, etchant concentration, and etching temperature) on the structure and surface active sites were investigated by the orthogonal experiment. The experimental results reveal that after etching with 0.5 mol/L of perchloric acid for 0.5 h at 60°C, the electrode weight loss of the PtNi catalyst is mainly attributed to the large loss of Ni atoms in film layer. This results in the reduced alloy phase in film layer and the appearance of Pt characteristic diffraction peak. The relative content of Pt on the surface of the film electrode increases significantly, and the total number of active sites also increases correspondingly. The binding energy of Pt4f_7/2 decreases by 0.19 eV, and the number of active sites involved in hydrogen release decreases, indicative of the reduced promotion effect of the PtNi catalyst on hydrogen release.     

纳米银刻蚀比色法检测褪黑激素

该文构建了一种基于氯金酸刻蚀球形纳米银检测褪黑激素的简单、高灵敏比色探针。纳米银可被氯金酸氧化刻蚀为Ag+,同时还原生成的纳米金沉积在刻蚀后的纳米银表面,导致其溶液的吸光度降低和颜色增强(由黄色变为橘黄色)。当向体系中加入褪黑激素时,氯金酸被还原,抑制了纳米银的刻蚀,从而使得溶液吸光度增加和颜色变浅。结果显示,在0.1 nmol/L~1.0 mmol/L范围内,褪黑激素浓度对数值(lgC)与其吸光度改变值(ΔA)呈良好的线性关系,线性方程为ΔA=0.049 8+0.516lgC,相关系数(R2)为0.996 4,检出限为0.09 nmol/L。该方法成功应用于人体尿液和葡萄中的褪黑激素的测定。     

Towards Long‐Term Photostability of Nickel Hydroxide/BiVO4 Photoanodes for Oxygen Evolution Catalysts via In Situ Catalyst Tuning

Increasing long‐term photostability of BiVO₄ photoelectrode is an important issue for solar water splitting. The NiOOH oxygen evolution catalyst (OEC) has fast water oxidation kinetics compared to the FeOOH OEC. However, it generally shows a lower photoresponse and poor stability because of the more substantial interface recombination at the NiOOH/BiVO₄ junction. Herein, we utilize a plasma etching approach to reduce both interface/surface recombination at NiOOH/BiVO₄ and NiOOH/electrolyte junctions. Further, adding Fe²⁺ into the borate buffer electrolyte alleviates the active but unstable character of etched‐NiOOH/BiVO₄, leading to an outstanding oxygen evolution over 200 h. The improved charge transfer and photostability can be attributed to the active defects and a mixture of NiOOH/NiO/Ni in OEC induced by plasma etching. Metallic Ni acts as the ion source for the in situ generation of the NiFe OEC over long‐term durability.     

大锥角光纤探针的制备

用熔拉法、腐蚀法、管腐蚀法、熔拉-腐蚀法、激光消融法等制备了光纤探针,对其外形进行了分析比较.熔拉法制作的探针,锥形过渡区细长,并且获得的探针锥角不大(8°～35°).腐蚀法与管腐蚀法可以使探针的锥形过渡区短,损耗小,锥角大(15°～65°),但在制备更大的锥角光纤探针时,表面开始变得粗糙.拉伸-腐蚀的方法制作光纤探针存在一个变锥度区.激光消融腐蚀法容易获得大锥角的探针,并且表面光滑.     

Dislocation Analysis for Large-sized Sapphire Single Crystal Grown by SAPMAC Method

In this paper,large-sized sapphire (230×210 mm,27.5 kg) was grown by SAPMAC method (sapphire growth technique with micro-pulling and shoulder-expanding at the cooled center). Dislocation peculiarity in large sapphire boule (0001) basal plane was investigated by chemical etching,scanning electron microscopy and X-ray topography method. The triangular dislocation etch pit measured is 7.6×101～8.0×102 cm-2,in which relative high-density dislocations were generated at both initial and final stages of crystal growth. The analysis of single-crystal X-ray topography shows that there are no apparent sub-grain boundaries; the dislocation lines are isolated and straight. Finally,the origins of low-density dislocation in sapphire crystal are discussed by numerical analysis method.     

微流控层流技术的研究

基于微型通道自身的层流特点而发展起来的多相层流技术,从最初的液-液微萃取开始,由于其结构加工简单、操作方便和分析功能强大,已逐渐发展成为一种加工分析方法,为微流控分析的研究应用打开了一个崭新的局面。本文概述了层流的基本原理,总结了近10年来在这方面的研究,包括层流界面间的分子扩散、转移现象和化学反应,以及层流刻蚀加工技术及其在制备纳米材料和在生命医学方面的应用。具体介绍了应用层流技术进行微芯片的加工制作,微型反应器的制备,离子、分子的分离分析,聚合物薄膜的形成和应用,微通道内有机合成反应的控制,溶液的浓度梯度控制以及在免疫检测中的应用,对细胞、生物大分子的操作控制,以及对生物试剂的预处理分析等。     

多孔硅纳米材料的制备及在高能锂电池中的应用

多孔硅纳米材料具有巨大的比表面积,可调控的物理化学性质,在药物治疗、传感、能源储存与转化等领域拥有巨大的应用前景。尤其在高能量密度锂离子电池领域,多孔硅由于其丰富的孔道结构能有效释放充放电过程中硅体积变化带来的巨大应力以及大大地缩短锂离子传输距离,而引起了人们的广泛研究兴趣。但是,开发简便快速的方法来合成结构可调变的多孔硅纳米材料仍是当前研究的挑战。近年来,一些用来合成多孔硅纳米材料的方法已有报道。我们基于本课题组最近的研究进展和近年来相关文献,比较详细综述了近年来多孔硅纳米材料的制备方法以及重点关注其在高能锂电池领域的应用。最后,对多孔硅纳米材料的未来发展方向做了进一步的展望。     

The Mosaic Structure of Zeolite Crystals

Zeolites are widely used in many commercial processes, mostly as catalysts or adsorbents. Understanding their intimate structure at the nanoscale is the key to control their properties and design the best materials for their ever increasing uses. Herein, we report a new and controllable fluoride treatment for the non‐discriminate extraction of zeolite framework cations. This sheds new light on the sub‐structure of commercially relevant zeolite crystals: they are segmented along defect zones exposing numerous nanometer‐sized crystalline domains, separated by low‐angle boundaries, in what were apparent single‐crystals. The concentration, morphology, and distribution of such domains analyzed by electron tomography indicate that this is a common phenomenon in zeolites, independent of their structure and chemical composition. This is a milestone to better understand their growth mechanism and rationally design superior catalysts and adsorbents.