Amorphous Crystalline Research Articles

A neural network based computational model to predict the output power of different types of photovoltaic cells.

In this article, we introduced an artificial neural network (ANN) based computational model to predict the output power of three types of photovoltaic cells, mono-crystalline (mono-), multi-crystalline (multi-), and amorphous (amor-) crystalline. The prediction results are very close to the experimental data, and were also influenced by numbers of hidden neurons. The order of the solar generation power output influenced by the external conditions from smallest to biggest is: multi-, mono-, and amor- crystalline silicon cells. In addition, the dependences of power prediction on the number of hidden neurons were studied. For multi- and amorphous crystalline cell, three or four hidden layer units resulted in the high correlation coefficient and low MSEs. For mono-crystalline cell, the best results were achieved at the hidden layer unit of 8.

Novel Polymeric Inhibitor for Corrosion of 57S Aluminium in 2M NaOH Solutions

In alkali solutions, corrosion of aluminium occurs at a high rate with the passivation of the metal accompanied by hydrogen evolution. Several organic compounds have been tried as corrosion inhibitors. The inhibition efficiency was brought down by the high-negative potential of the reaction, which would simply repel any organic compound in the electrical double layer (Antropov, 1961). Nevertheless, quite a large number of organic compounds inhibit corrosion in dilute solutions but eventually fail at higher concentrations. Carbonic acids (Horiguchi et al., 1966), aliphatic and aromatic amines (Sarangapani et al., 1984), diketones (Horiguchi et al., 1966), phenolic compounds (Subramanyan et al., 1971) alkaloids (Subramanyan and Ramakrishnaiah, 1971) alizarin derivatives were tried as inhibitors. The present investigation aims at the development of polyaniline as corrosion inhibitor. In the present study, addition of ZnO in solution shifted the corrosion potential to noble direction by forming a film. The conductivity of the film has been enhanced by incorporating polyaniline. The corrosion of aluminium has been inhibited by the combined action of polyaniline and ZnO. The formation of an oxide film encapsulated with polyaniline prevented the dissolution of aluminium. Inhibitors of aluminium corrosion in aqueous medium have been reviewed. In aqueous solution, the surface film formed on aluminium is of duplex in nature consisting of an inner amorphous Al2O3and outer crystalline aluminium oxides. These films inhibit corrosion in the initial stages but weaken this film due to the incorporation of OH– ions into this structure and accelerate corrosion. In presence of excess OH– ions, aluminium dissolves to form aluminate. Additions of organic compounds inhibit to a lesser degree. Owing to the high negative electrode potentials, they desorb and accelerate corrosion. Most of the organic inhibitors inhibit hydrogen evolution reaction to some extent. The purpose of this work (A. Elango et al., 2010) is to show how to develop inhibition 57S aluminium in 2M NaOH solution. The results of the work clearly reveal that the 0.2 M ZnO with 700 ppm polyaniline in N-methyl-2-pyrrolidone solution is found to offer inhibition up to 71.2 per cent. The paper deals with the development of newer inhibitor based on polyaniline. Gravimetric and galvanostatic methods were employed to evaluate inhibition efficiency.

The equation of state of polymers. Part III: Relation with the compensation law.

The properties of amorphous polymers and of organic compounds under pressure are interpreted in the framework of the modified Van der Walls Equation of State (mVW-EOS) the Vogel-Fulcher-Tamann (VFT) law and of the compensation law. We have shown recently that polymers and organic compounds in amorphous liquid and crystalline states verify the mVW-EOS which depends on three parameters, [Formula: see text] [Formula: see text] and [Formula: see text]. In this paper we compare the characteristic pressure [Formula: see text] of the mVW-EOS to the various pressures [Formula: see text] deduced from thermodynamic and kinetic properties of polymers in the liquid and solid states. [Formula: see text] and [Formula: see text] are: a) the enthalpy and volume change at the melting and glass transitions (the glass being isotropic or oriented and annealed below [Formula: see text] at various aging conditions); b) the activation parameters of individual [Formula: see text] and cooperative [Formula: see text] motions in crystalline liquid and amorphous polymers studied by dielectric or mechanical spectroscopy; and c) the activation parameters of amorphous (solid and liquid) polymers submitted to a deformation depending on the time frequency temperature and strain rate. For a same material, whatever its state and whatever the experimental properties analyzed (dielectric and mechanical relaxation, viscosity, auto-diffusion, yielding under hydrostatic pressure), we demonstrate that [Formula: see text], ([Formula: see text] Grüneisen parameter, [Formula: see text] compressibility). In all polymers and organic compounds (and water), these pressures, weakly dependent on T and P near [Formula: see text] and [Formula: see text] at low pressure are characteristic of the H-H inter-molecular interactions. It is shown that the two empirical Lawson and Keyes relations of the compensation law can be deduced from the mVW-EOS.

Reorganization of semicrystalline polymers on heating: Analyzing common misconceptions in the interpretation of calorimetric data. Response on the “Comment on “Re-exploring the double-melting behavior of semirigid-chain polymers with an in-situ combination of synchrotron nanofocus X-ray scattering and nanocalorimetry” by Dimitri A. Ivanov et al. [Euro. Polym. J. 81 (2016) 598–606.

In our recent article entitled “re-exploring the double-melting behavior of semirigid-chain polymers with an in-situ combination of synchrotron nanofocus X-ray scattering and nanocalorimetry” (European Polymer Journal 81 (2016) 598–606), we investigated complex thermal behavior of a typical semirigid-chain polymer, poly(trimethylene terephthalate), PTT. In the comment on our paper published by Furushima and colleagues (EUROPOL_2017_495), our interpretation of the multiple melting phenomenon was seriously questioned. In particular, it was argued that the main drawback in our paper was due to the fact that the critical heating rate above which the PTT structure does not reorganize after isothermal melt crystallization at 180°C should be 2000°C·s−1, i.e. higher than the rate of 1000°C·s−1 used in our experiments. It is noteworthy that the authors of the Comment performed all their experiments on a different grade of PTT, which makes quantitative comparison with the recrystallization rates in our experiments problematic. In the present paper, we employ a combination of X-ray scattering with fast single-photon-counting X-ray detection and custom-built ultrafast chip calorimeter to show that the claims of Furushima and colleagues are not relevant to our case and, therefore, cannot be generalized. Indeed, even for a PTT sample melt-crystallized at 150°C, which recrystallizes on heating much faster than the sample crystallized at 180°C, the critical heating rate is safely below 500°C·s−1. To further clarify the issue, we discuss on a general misconception in the literature concerning the interpretation of double melting peaks in DSC traces as being indicative of a melting/recrystallization process. Since many works in the field including the discussed one are based entirely on calorimetric data, the direct information on the structure is simply missing. Therefore, such interpretations of the thermal behavior evoking the so-called “single crystal population” are clearly inadequate. By contrast, on the basis of on-time X-ray scattering recorded simultaneously with ultrafast chip calorimetry we unambiguously show that even in the absence of reorganization processes a uniform population of PTT crystals formed at isothermal conditions exhibits double melting. In agreement with our earlier publications (e.g., Macromolecules 41 (2008) 9224–9231) this is explained by strong interactions between amorphous and metastable crystalline regions, which are very characteristic for the semirigid-chain polymer family.

Growth of organic crystals via attachment and transformation of nanoscopic precursors

A key requirement for the understanding of crystal growth is to detect how new layers form and grow at the nanoscale. Multistage crystallization pathways involving liquid-like, amorphous or metastable crystalline precursors have been predicted by theoretical work and have been observed experimentally. Nevertheless, there is no clear evidence that any of these precursors can also be relevant for the growth of crystals of organic compounds. Herein, we present a new growth mode for crystals of DL-glutamic acid monohydrate that proceeds through the attachment of preformed nanoscopic species from solution, their subsequent decrease in height at the surface and final transformation into crystalline 2D nuclei that eventually build new molecular layers by further monomer incorporation. This alternative mechanism provides a direct proof for the existence of multistage pathways in the crystallization of molecular compounds and the relevance of precursor units larger than the monomeric constituents in the actual stage of growth.

Reaction of amorphous/crystalline SiOC/Fe interfaces by thermal annealing

The development of revolutionary new alloys and composites is crucial to meeting materials requirements for next generation nuclear reactors. The newly developed amorphous silicon oxycarbide (SiOC) and crystalline Fe composite system has shown radiation tolerance over a wide range of temperatures. To advance understanding of this new composite, we investigate the structure and thermal stability of the interface between amorphous SiOC and crystalline Fe by combining various experimental techniques and simulation methods. We show that the SiOC/Fe interface is thermally stable up to at least 400 °C. When the annealing temperature reaches 600 °C, an intermixed region forms at this interface. This region appears to be a crystalline phase that forms an incoherent interface with the Fe layer. Density functional theory (DFT) Molecular dynamics (MD) is performed on the homogeneous SiFeOC phase to study the early stages of formation of the intermixed layer. Both experimental and simulation results suggest this phase has the fayalite crystal structure. The physical processes involved in the formation of the intermixed region are discussed.

The impact of Si/Al ratio on properties of aluminosilicate aerogels

The Si/Al ratio is a key parameter of acid-base, structural, textural and, consequently, catalytic properties of amorphous crystalline (micro- and mesoporous) aluminosilicates. The changes of structural and textural characteristics of Al-Si aerogels with gradual increase of aluminum content are investigated. Aerogels were prepared via sol-gel method using prehydrolysed tetraethoxysilane and aluminium isopropoxide stabilized by acetylacetone. The gelation of the obtained sols took place in the presence of ammonia with the following drying in supercritical isopropanol. It was shown all aluminum reacts with prehydrolyzed tetraethoxysilane forming spherical particles in case the content of Al in the samples is less than 20 mol %. Aluminum drives the increase of interparticle coupling leading to the particle agglomeration, which is associated with the increase of the particle size and decrease of specific surface area and pore volume. For the samples with the aluminum content of >50 mol % the formation of pseudoboehmite plate-like particles is observed. The pseudoboehmite particles prevent the sintering of SiO2 particles that leads to the increase of the aerogel specific surface area and pore volume. In case the high aluminum content (>80 mol %) the silica particles serve as a connector between boehmite plates. The ratio between Brønsted and Lewis acid sites decreases gradually with the increase of aluminum content of the aluminosilicate aerogels.

Effect of SiO2/Al2O3 Molar Ratio on Microstructure and Properties of Phosphoric Acid-based Metakaolin Geopolymerss

The phosphoric acid-based metakaolinite geopolymeric materials with different SiO2/Al2O3 molar ratios were prepared from metakaolinite, Al2O3 powder and phosphoric acid. X-ray diffraction (XRD), Thermogravimetry and Differential Scanning Calorimeter (TG-DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to determine the reaction process and phase formation. The results indicated that different SiO2/Al2O3 ratios raw materials can generate geopolymers composition of the amorphous phase and quartz crystalline phase. The still existed quartz peaks indicate that quartz from metakaolinite did not totally take part in the chemical reaction or dissolve into the gel phase of geopolymers. The best performance was observed in the geopolymeric material prepared with SiO2/Al2O3 molar ratio of 1.4 due to the proper obtained Si-O-Al-O-P-O- bonds in geopolymeric structures. The acid-based geopolymers were stable below 1450 °C. These geopolymers have a potential use in fireproofing materials, since they display important high temperature stability.

Nanostructural Characterization of the Fe3O4/ZnO Magnetic Nanocomposite as an Application in Medicine

In the present work, we synthesize Fe3O4/ZnO nanocomposite by sol-gel method using iron nitrate, ethylene glycol, zinc acetate dehydrate, and ammonium carbonate as precursors. Amorphous matrix and crystalline grains were formed in composite as well. The nanostructural properties of the nanocomposite were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and colloidal stability was checked out by Zeta potential. The biological effects of Fe3O4/ZnO nanocomposite were investigated by microculture tetrazolium test (MTT) against MCF-7 breast cancer cells as usage in medicine. Crystallite size, lattice strain, and dislocation density of the nanoparticles were estimated with Williamson-Hall method. The obtained results show that the highest death rate of Michigan Cancer Foundation-7 (MCF-7) cancer cells was for Fe3O4/ZnO nanocomposite with the molar ratio is 1:10 in the lower concentration (49 μ g/ml). Therefore, these nanocomposites due to their small size, colloidal stability, magnetic properties, and nontoxicity can be a good candidate as option in medicine application.

Cover Caption

May Online Cover: Moisture‐mediated interactions between deliquescent crystalline ingredients and amorphous solids, from Feature Article “Moisture‐Mediated Interactions Between Amorphous Maltodextrins and Crystalline Fructose” by Alpana Thorat, Krystin N. Marrs, Mohamed K. Ghorab, Vincent Meunier, Laurent Forny, Lynne S. Taylor, and Lisa J. Mauer. Image credits: Matt Allan, Seda Arioglu, and Julieta Ortiz, Purdue Univ. students. p. 1142.

The effects of thin coatings on the mechanical properties and resistance to annealing-induced embrittlement of bulk metallic glass

The effect of thin coating on the strength, plasticity and resistance to annealing-induced embrittlement was investigated for Zr50.7Cu28Ni9Al12.3 bulk metallic glass (BMG). To maintain the BMG structure in the most extent, very thin amorphous CuZr and crystalline W coatings were used. The crystalline coating performed much better in improving BMG plastic deformation than the amorphous one, for its superior retarding effect on shear band (SB) dynamics. Besides the coatings, softer layers near the sputtered surfaces also contributed to the enhanced plasticity of the coated BMG. The presence of these softer layers also led to the slightly lower strength of both amorphous CuZr and crystalline W coated BMGs relative to the uncoated ones. The BMG with crystalline W coating exhibited much better resistance to annealing-induced embrittlement than the amorphous CuZr-coated and uncoated ones, due to its much enhanced decomposition processes upon annealing. These experimental results provide useful guidance on choosing suitable coating materials to elevate BMG plasticity and avoid annealing-induced embrittlement.

Influnce of exposure with Xe radiation on heterojunction solar cell a-SiC/c-Si studied by impedance spectroscopy

The photovoltaic efficiency of heterostructures a-SiC/c-Si may be the same or even better in comparison with conventional silicon structures when suitable adjustment of technological parameters is realized. The main advantage of heterojunction formed amorphous SiC thin film and crystalline silicon compared to standard crystalline solar cell lies in high build-in voltage and thus a high open-circuit voltage. Solar cells can be exposed to various influences of hard environment. A deterioration of properties of heterostructures (a-SiC/c-Si) due to irradiation is examined in our paper using impedance spectroscopy method. Xe ions induced damage is reflected in changes of proposed AC equivalent circuit elements. AC equivalent circuit was proposed and verified using numerical simulations. Impedance spectra were also measured at different DC bias voltages due to a more detailed understanding correlation between Xe ions induced damage and transport phenomenon in the heterostructure.

Enhanced pulmonary absorption of poorly soluble itraconazole by micronized cocrystal dry powder formulations

Micronized cocrystal powders and amorphous spray-dried formulations were prepared and evaluated in vivo and in vitro as pulmonary absorption enhancement formulations of poorly soluble itraconazole (ITZ). ITZ cocrystals with succinic acid (SA) or l-tartaric acid (TA) with a particle size diameter of <2μm were successfully micronized using the jet-milling system. The cocrystal crystalline morphologies observed using scanning electron microscopy (SEM) suggested particle shapes that differed from those of the crystalline or spray-dried amorphous ITZ. The micronized ITZ cocrystal powders showed better intrinsic dissolution rate (IDR) and pulmonary absorption profile in rats than that of the amorphous spray-dried formulation and crystalline ITZ with comparable particle sizes. Specifically, in rat pharmacokinetic studies following pulmonary administration, micronized ITZ-SA and ITZ-TA cocrystals showed area under the curve from 0 to 8h (AUC0–8h) values approximately 24- and 19-fold higher than those of the crystalline ITZ and 2.0- and 1.6-fold higher than the spray-dried ITZ amorphous values, respectively. The amorphous formulation appeared physically instable during the studies due to rapid crystallization of ITZ, which was its disadvantage compared to the crystalline formulations. Therefore, this study demonstrated that micronized cocrystals are promising formulations for enhancing the pulmonary absorption of poorly soluble compounds.

Flexible and stretchable polyurethane/waterglass grouting material

Flexibility and stretchability are of ever increasing importance in constructing high-performance grouting materials. Herein, a facile, effective and cost-efficient strategy to make organic-inorganic hybrid chemical grouting material in a “flexible and stretchable” way was based on polymerization of carbon double bond and excellent synergistic interactions among N-Methylol acrylamide, butenediol, waterglass and prepolymer. Upon the optimal percentages of waterglass (44%), N-Methylol acrylamide (3.5%), butenediol (1.5%), Alkylphenol polyoxyethylene (OP-9, 0.5%), 2,2′-azobis[2-(2-imidazolin-2-yl)propane] (0.35%), 2,2-dimorpholinodiethylether (DMDEE, 0.15%) and prepolymer (50%), the obtained polyurethane/waterglass grouting material with three-dimensional interpenetrating network structure displayed an excellent flexibility, satisfactory compressive strength of 13.4MPa at 50% compression state, and relatively large elongation of up to 60% with a stable stretching for 200times. The grouting material was mainly composed of amorphous polyurethane and crystalline polysilicic acid/NaHCO3/Na2CO3 composite, and its probable formation mechanism was proposed. Additionally, the grouting material possessed favorable thermal stability and repairment performance for roadway cracks. This work may open a simple and convenient avenue for the preparation of organic-inorganic hybrid chemical grouting material with flexibility and stretchability.

A facile synthesis about amorphous CoS2 combined with first principle analysis for supercapacitor materials

The structure and electrochemical properties of amorphous CoS2 and crystalline CoS2 have been studied with both experimental characterization and theoretical calculations. In the field of experimental characterization, a facile chemical precipitation method is used to synthesize amorphous and crystalline CoS2 samples with calcining temperatures of 200 and 280 °C, respectively. Comparing with crystalline CoS2, amorphous structure of CoS2 manifests great electron conductivity, effective porous structure, and exhibit a high specific capacitance of 996.16 F g−1 at current density of 0.5 A g−1, excellent rate capability of 89.8% retention with the current density ranging from 0.5 to 5 A g−1, and a great cycling stability of 97.6% retention after 10,000 cycles at 2 A g−1 in 6 mol L−1 KOH aqueous electrolyte. In the area of theoretical calculation, we used the first principle and obtained the band structure with band gap of 0.00369 eV and DOSs with high locality of D-orbital from 69.88689 electrons/eV main peak, in the CoS2 amorphous. The result confirms that amorphous CoS2 have higher conductivity than crystalline CoS2 in theory. In addition, the as-assembled asymmetric supercapacitor of Co-S-200//AC also exhibits the maximum specific capacitance of 104 F g−1 within a cell voltage from 0 to 1.5 V at current density of 0.5 A g−1 and indicates a great cycling stability of 95.68% and excellent capacitance behavior. All results demonstrate a great potential of amorphous CoS2 active material for supercapacitors.

Polyglycerol-based organic-inorganic hybrid adhesive with high early strength

The rapid achievement of high strength adhesive is of ever increasing importance for underground construction. Herein, a simple and effective strategy to make an adhesive in a “high early strength” way was based on excellent crosslinking and synergistic interactions among tripolyglycerol, waterglass and polyaryl polymethylene isocyanate (PAPI). The resultant organic-inorganic hybrid adhesive with three-dimensional interpenetrating network structure showed an excellent mechanical performance, the compressive strength could reach more than 50 and 60MPa after curing for 2 and 4h, respectively. The adhesive was mainly composed of amorphous polyurethane and crystalline polysilicic acid/NaHCO3 composite, and its probable formation mechanism was proposed. Furthermore, the adhesive was thermally stable below 260°C and presented a favorable adhesion performance for dry/wet sands with various sizes. This work may open a simple and convenient avenue for the preparation of organic-inorganic hybrid adhesive with high early strength.

Microgroove machining on crystalline nickel phosphide plating by single-point diamond cutting

Electroless nickel phosphide (Ni–P) plating is used as a new mold material to fabricate microgrooves on glass molding process because of its excellent mechanical properties and machinability. Amorphous Ni–P will be crystallized at high temperature during the glass molding process. Crystalline Ni–P plating leads to mold deformation, which may reduce the mold accuracy and shorten the service life. In this study, the amorphous plating is heated to its annealing temperature at nearly 600 °C to make it transform to crystalline state in advance. Thus, the hardness of the plating increased from 614 to 941 HV; the deformation of the mold with crystalline plating similar to glass molding condition is removed by ultraprecision turning. Finally, microgrooves are fabricated on crystalline Ni–P plating. In the experiments, matrices with amorphous plating and crystalline plating are used in microgroove machining on an ultraprecision machine. Subsequently, machined form accuracy and surface quality for the two plating layers are compared. Under the condition of different cutting speeds, the surface roughness of the crystalline Ni–P plating distributed in the interval of about 60 nm; the amorphous Ni–P plating distributed in the interval of about 80 nm correspondingly. The results proved that the microgrooves machined on the crystalline plating exhibited better performance than its amorphous counterpart.

Charge-Transfer through Ultrathin Film TiO2 on n-Si(111) Photoelectrodes: Experimental and Theoretical Investigation of Electric Field-Enhanced Transport with a Nonaqueous Redox Couple

Ultrathin film amorphous (a-TiO2) and anatase crystalline (c-TiO2) titanium dioxide were investigated as corrosion passivation layers on n-type Si(111). Varying thicknesses of TiO2 (5–60 A) were deposited on n-Si(111)–CH3 substrates by atomic layer deposition (ALD) at 150 and 240 °C, thus yielding a-TiO2 and c-TiO2, respectively. The phase and morphology of the TiO2 films were determined using a combination of XRD, Raman spectroscopy, XPS, AFM and SEM. The electronic properties of a-TiO2 and c-TiO2 films were compared using 4-point sheet resistance and electrochemical impedance spectroscopy. Substrates functionalized with c-TiO2 exhibited higher conductivity, lower charge transfer resistance, and comparable anticorrosion behavior to a-TiO2. The photoelectrochemical response of n-Si(111)–CH3|TiO2 electrodes as a function of TiO2 thickness was characterized using cyclic voltammetry with ferrocene in acetonitrile. A thickness of 20 or 40 A was required to block charge transport through a-TiO2 and c-TiO2, res...

Rietveld refinement for Sr(Ba)-bearing ye'elimite

Ye'elimite-containing cements are of growing research interest owing to their characteristic properties. Strontium (barium) (Sr(Ba))-bearing ye'elimite is synthesised by the substitution of Sr2+(Ba2+) ions for Ca2+ ions in ye'elimite. Here, Rietveld refinement for Sr(Ba)-ye'elimite is reported. The effect of strontic and baric substitutions on the crystal system of ye'elimite is analysed. Additionally, the crystalline phases and potential ACn (amorphous and non-quantified crystalline phase) contents, in clinkers containing Sr(Ba)-ye'elimite, are determined. As substitutions increase, the crystal system of Sr-bearing ye'elimite transforms from an orthorhombic system to a cubic system, but Ba-bearing ye'elimite remains cubic throughout the process. In the clinkers, the Sr-bearing ye'elimite reaches 97% (wt%) and the Ba-bearing ye'elimite is greater than 94% (wt%), with insignificant amounts of amorphous and non-quantified crystalline phase (ACn) contents. With a higher degree of substitutions, the lattice parameters of Sr(Ba)-bearing ye'elimite exhibit linear growth trends.

High-Quality Bi2Te3 Single Crystalline Films on Flexible Substrates and Bendable Photodetectors**Supported by the National Basic Research Program of China under Grant No 2012CB619200, the National Natural Science Foundation of China under Grant Nos 61290304, 11074265 and 11174307, the Natural Science Foundation of Shanghai under Grant No 16ZR1441200, and the Frontier Science Research Project (Key Programs) of Chinese Academy of Sciences

Recently, great efforts have been made in the fabrication of arbitrary warped devices to satisfy the requirement of wearable and lightweight electronic products. Direct growth of high crystalline quality films on flexible substrates is the most desirable method to fabricate flexible devices owing to the advantage of simple and compatible preparation technology with current semiconductor devices, while it is a very challenging work, and usually amorphous, polycrystalline or discontinuous single crystalline films are achieved. Here we demonstrate the direct growth of high-quality Bi2Te3 single crystalline films on flexible polyimide substrates by the modified hot wall epitaxy technique. Experimental results reveal that adjacent crystallites are coherently coalesced to form a continuous film, although amounts of disoriented crystallites are generated due to fast growth rate. By inserting a quartz filter into the growth tube, the number density of disoriented crystallites is effectively reduced owing to the improved spiral interaction. Furthermore, flexible Bi2 Te3 photoconductors are fabricated and exhibit strong near-infrared photoconductive response under different degrees of bending, which also confirms the obtained flexible films suitable for electronic applications.