Volume 8, Issue 4, April 2017

Recent advancements in the field of Nanomaterials and Nanotechnology

Ashutosh Tiwari

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 322-323
DOI: 10.5185/amlett.2017/4001

In 1959 a renowned physicist Richard Feynman in his talk “There's Plenty of Room at the Bottom” discussed about nanotechnology in which he described the possibility of synthesis via direct manipulation of atoms. The term "nano-technology" was first used by Norio Taniguchi in 1974. Nanotechnology works at the very initial level of atoms and molecules for the living systems. Nanotechnology accelerates the developments of many techniques and tools for society. At nanoscale, unifying features of nature give a new foundation for fundamental research and new potential applications. Nanotechnology brings knowledge, innovation, and integration of technology together with novel nanomaterials. Nanotechnology research has shown developments due to innovative, advantageous properties of nanomaterials.

Deflection behavior of focused-ion-beam deposited carbon nanocantilever and overhung structures

Prashant K Sarswat; Madhusudan Jagannathan

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 324-330
DOI: 10.5185/amlett.2017.6889

Elastic properties of nanostructures are crucial for the adequate design and long term use of nano/micro-electro-mechanical system (NEMS/MEMS) as well as their utility in nanoindentation. Carbon nanostructures were fabricated by focused ion beam (FIB) assisted deposition and milling using Naphthalene (C10H8) as a precursor gas. Cantilevers of size 3-10 µm were fabricated and their elastic properties were monitored. An end point load was applied by successive deposition of Pt or carbon in a form of vertical column. Euler–Bernoulli beam theory was applied to examine the mechanical properties of the cantilever. It has been observed that expected deflection of the carbon nano-cantilever is significantly different compared to most of the reported micro or nano-sized carbon or diamond structures. Initial investigation of such a discrepancy suggests that Ga implantation and presence of core-shell type structure are the main causes of altered mechanical properties. 

Stoichiometric dependent optical limiting in PLD SiOx thin films

Partha P. Dey; Alika Khare

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 331-335
DOI: 10.5185/amlett.2017.6931

In this letter, optical limiting property of the insufficiently oxidized silicon oxide (SiOx) thin films is reported. Films were deposited by Pulsed Laser Deposition technique using Q-switched Nd: YAG laser (532 nm) onto fused silica substrate at a substrate temperature of 400 °C by varying the O2 pressure in the range of 5×10 -5 to 0.5 mbar. Energy Dispersive X-Ray spectra showed the increase in oxygen content with increasing O2 pressure. Raman spectra of SiOx films depicted the presence of micron sized clusters composed of nanocrystalline Silicon embedded in uniform matrix of oxidized amorphous Silicon. The open Z-scan of the thin films, under cw He-Ne laser irradiation, showed strong reverse saturation absorption (RSA) features and non linear absorption (NLA) coefficient, β, was found to be decreasing from 23.5 cm/W to 1.64 cm/W,  with increase in O2 pressure from 5×10 -5 to 10 -1 mbar, respectively. Also, the SiOx films except that with maximum oxygen content showed optical limiting, where limiting threshold increases with increasing transparency controlled by oxygen content. The key feature of the present work is the tunability in linear absorption, nonlinear RSA and optical limiting in the SiOx films which can be used as novel material for optical switching application.

Polymer-nanoparticle coatings on macroporous silicon matrix

Liudmyla A. Karachevtseva; Mykola T. Kartel; Oleg O. Lytvynenko; Volodymyr F. Onyshchenko; Kostyantyn A. Parshyn; Olena J. Stronska

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 336-341
DOI: 10.5185/amlett.2017.1412

We synthesized light-emitting coatings of CdS nanocrystals in polyethyleneimine and polyethyleneimine with multiwall carbon nanotubes on macroporous silicon. The photoluminescence of CdS nanocrystals in polyethyleneimine on oxidized macroporous Si is more intense in comparison with substrates c-Si, macroporous Si, and macroporous Si with a microporous layer, and is maximal for structures with maximal intensity of the local electric field at the Si-SiO2 interface. This indicates a significant decrease of non-radiative recombination in the CdS-polyethyleneimine layer due to electron flow from the silicon matrix to the nanocrystal layer. The photoluminescence of polyethyleneimine with carbon multiwall nanotubes on macroporous Si with a microporous layer is about six times more intense in comparison with substrates c-Si, macroporous Si and oxidized macroporous Si. This indicates a non-radiative proton recombination decrease due to hydrogen atoms on the boundary between Si matrix with microporous layer and “polymer-nanoparticles” coating. 

La-doped CH3NH3BaI3: A promising transparent conductor

Jiban Kangsabanik; Aftab Alam

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 342-345
DOI: 10.5185/amlett.2017.1416

Hybrid perovskites (CH3NH3PbI3) is one of the most promising novel materials for solar harvesting. Toxicity of lead (Pb), however, has always remained a concern. We investigated the electronic structure of complete replacement of Pb by alkaline earths (Ca, Sr, Ba) and found them to be wide band gap (Eg) semiconductors (band gap ~ 3.7 to 4.0 eV), and hence not suitable as absorber material. This opens up a new avenue to explore these materials as transparent conductor (TC). We doped CH3NH3BaI3 (largest Eg) with La, which shifts its Fermi level (EF) at conduction band bottom and induces states at EF for conduction. This is precisely what is required for a transparent conductors. Optical and transport properties simulated from linear response (within Density Functional Theory (DFT)) calculations suggested it to be a very good TC material with a high figure of merit (s/a), where s is the electrical conductivity and a is the optical absorption coefficient. This claim is also supported by our calculated results on density of states at EF, effective mass, carrier concentration etc. at various La-doping. We propose CH3NH3(Ba1-xLax)I3  (x£12.5%) to be a good TC material to be used  in an all perovskite solar cell. 

Industrial grade LaCe1.85Pr0.03Nd0.06Ox/Na2CO3 nanocomposite for novel low-temperature semiconductor-ionic membrane fuel cell

Yanyan Liu; Wei Zhang; Baoyuan Wang; Muhammad Afzal; Chen Xia; Bin Zhu

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 346-351
DOI: 10.5185/amlett.2017.7052

Doped ceria electrolytes have attracted intensive attentions owing to their high ionic conductivity, low activation energy, good catalytic activity and feasibility for intermediate or even low temperature operations. This work reports an interesting industrial grade rare earth LaCe1.85Pr0.03Nd0.06-oxide composited with sodium carbonate (LCPN-oxide/Na2CO3) as the electrolyte in solid oxide fuel cells (SOFCs). The ‘symmetrical’ anode/electrolyte/cathode SOFC devices are fabricated using LCPN-oxide/Na2CO3 electrolyte and the lithiated transition metal oxide Ni0.8Co0.15Al0.05LiO2 (NCAL) pasted onto nickel foam as both anode and cathode. A power density of 362 mW/cm 2 is achieved at 550 o C for this device. A novel fuel cell device, semiconductor-ionic membrane fuel cell (SIMFC) is introduced here using the LCPN-oxide/Na2CO3 and NCAL as the mixed semiconductor-ionic conductor layer. The peak power density for this new energy conversion device reaches 916 mW/cm 2 at 550 o C with an open circuit voltage of 1.05 V. The results demonstrate that industrial grade LCPN-oxide/Na2CO3 can provide a new approach to utilize the enriched natural resources for next-generation cost-effective fuel cells. 

Synthesis, characterization and bio-evaluation of core-shell QDs with ZnSe, CdS and CdSe combinations

Sreenu Bhanoth; Anuraj Kshirsagar; Pawan K Khanna; Aakriti Tyagi; Ankita Leekha; Vijay Kumar; Anita Verma

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 352-361
DOI: 10.5185/amlett.2017.6495

Present article describes one-pot, two-stage, in-situ controlled atmosphere method for synthesis of core-shell quantum dots (QDs) comprising of ZnSe, CdS and CdSe combinations e.g. CdS/CdSe, ZnSe/CdS and ZnSe/CdSe. The present method emphasizes on creating an effective surface passivation of core as well as formation of passivated shell via utilization of cyclo-octeno-1, 2, 3-selenadiazole as a precursor for selenium. Synthesis of ZnSe/CdS was compared by using two different selenium precursors viz cyclo-octeno-1, 2, 3-selenadiazole (C8-SDZ) and cyclo-hexeno-1, 2, 3-selenadiazole (C6-SDZ). Optical properties (UV-Visible and PL spectroscopy) indicate narrow peak width with band gap ranging in between 2.30 eV to 2.56 eV. The XRD analysis revealed the formation of respective core-shell QDs with zinc blende crystal structure. TEM analysis showed formation of spherical shaped core-shell QDs with lattice spacing of 0.35 nm due to presence of (111) crystal plane.  By virtue of the excellent optical properties of ZnSe/CdS core shell QDs, this was subjected to bio-evaluation in terms of cytotoxicity and therapeutic efficacy. Approximately, 65% bio-toxicity was observed in MCF-7 with negligible haemolysis by ZnSe/CdS QDs. About, 34% tumour regression was shown by ZnSe/CdS QDs, as against 93% observed by Mitomycin C (Positive control) with respect to placebo (PBS).

Preparation of partially acetylated chitin nanofiber/polyethylene composite film

Keisho Iimori; Ryo Endo; Kazuya Yamamoto; Jun-ichi Kadokawa

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 362-367
DOI: 10.5185/amlett.2017.1451

Chitin is widely distributed in nature and an important renewable resource. However, it has been difficult to provide a wide variety of material applications from chitin, due to poor solubility and processability. In this study, we performed surface modification of self-assembled chitin nanofibers (CNFs) by acetylation and their composite fabrication with a commodity plastic, low density polyethylene (LDPE). The self-assembled CNF dispersion with DMF was first prepared by regeneration from a chitin ion gel with an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), using methanol, followed by exchange of a dispersion medium according to the previously reported method by us. Surface acetylation of the product was then performed by reaction of acetic anhydride in the dispersion to obtain partially acetylated CNFs, which formed a film by isolation. The composites of the film with LDPE with the different weight ratios were fabricated by pressing at 170 o C at 0.1 MPa. The SEM measurements of the products observed the morphologies that LDPE interpenetrated from surfaces into cross-sections of the partially acetylated CNF films with increasing the LDPE ratios. The tensile testing of the composite films indicated reinforcing effect of LDPE present in the composites.

Cytotoxicity studies of II-VI semiconductor quantum dots on various cancer cell lines

Sreenu Bhanoth; Aakriti Tyagi; Anita K. Verma; Pawan K. Khanna

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 368-376
DOI: 10.5185/amlett.2017.6456

Enhanced understanding of diseases at the molecular level has made a paradigm shift towards identifying new biological indicators especially in nanomaterials. It is important to make Quantum Dots (QDs) more than just passive bio-probes/labels for biological imaging and cellular studies as they offers “smart” multifunctional nano-platforms. For any biomedical, optoelectronic device application, evaluation of cytotoxicity coupled with cellular uptake and internalization of QDs are imperative. This paper describes the cytotoxic studies of hydrophilic and hydrophobic QDs, capped with polyvinyl pyrrolidone (PVP) and oleic acid in human breast adenocarcinoma MCF-7, Human Embryonic Kidney (HEK-293) and Ehrlich Ascites Carcinoma (EAC) cancer cells that indicated a concentration and time dependent response in a 48 hr assay. The enhanced fluorescence emitted from the cytoplasm confirmed that the QDs were efficiently internalized by the cells. 35% cytotoxicity was observed by core-shell ZnSe/CdSe QDs in HEK-293 cells, while the hydrophobic CdSe exhibited less cytotoxicity in both MCF-7 and EAC cell lines in 48 hrs. Increased LDH leakage and decreased MTT reduction was observed in a time dependent manner. The decrease rate of LDH was found in PVP-CdSe relative to the value obtained from untreated/control cells post 24 hr. The oleic acid coating renders the core-shell CdSe QDs to be more hydrophobic thus making them less toxic due to possibly weak interaction with the cells, and low ionization of cadmium. Based on our experimental observation the sequence of cytotoxicity of tested QDs was hydrophilic greater than hydrophobic in all three cell lines. 

Porous hydroxyapatite scaffolds fabricated from nano-sized powder via honeycomb extrusion

Mohammed Elbadawi; James Meredith; Mosalagae Mosalagae; Ian M. Reaney

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 377-385
DOI: 10.5185/amlett.2017.7063

In this study, we have developed hydroxyapatite (HA) scaffolds for synthetic bone graft from nano-sized HA particles using ceramic extrusion. We also demonstrate that these HA scaffolds show enhanced compressive strength (29.4 MPa), whilst possessing large pore sizes (> 600 µm) that are suitable for bone grafting. The extrusion process involved forming a ceramic paste by mixing the HA powder with a binder and distilled water. The ceramic paste was then fabricated using a ram extruder that was fitted with a honeycomb die to impart large, structured pores. Several green bodies were extruded and then subjected to the same drying and thermal debinding treatment. The samples underwent three different sintering temperatures and two varied dwell times, in order to determine the optimum sintering parameters. The scaffolds were then analysed for their chemical, physical, mechanical and biological properties to elucidate the effects of the sintering parameters on extruded HA scaffolds. The results revealed that the nano-sized particles exhibited a high sinterability, and XRD analysis showed phase purity until 1300 o C. At 1300 o C, trace amounts of phase impurities were detected, however, scaffolds sintered at this temperature exhibited the highest mean compressive strength. The findings demonstrated that traces of phase impurities were not detrimental to the scaffold’s compressive strength. In addition, scanning electron microscopy and density measurements revealed a highly densified solid phase was attained.

Determination of optimum cation to anion (Cd:S) ratio for the synthesis of mono sized CdS quantum dots through optical properties

Jai Kumar B; Sumanth Kumar D; Mahesh H. M

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 386-392
DOI: 10.5185/amlett.2017.6918

The CdS quantum dots (QDs) were synthesized using double injection aqueous method and systematic studies were carried to determine optimum cation to anion (Cd:S) ratio to obtain mono sized CdS QDs. An efficient and convenient method is designed by utilizing the optical properties (absorbance and transmission spectra) as qualitative tool. CdS QDs was synthesized by varying cadmium and sulfur concentration from 0.01M to 0.1M and 0.01M to 0.05M respectively keeping MPA and other precursors constant. Through Concentration Optimization by Optical Spectra (COOS) method, it was found that for 0.02M sulfur and 0.04M MPA, 0.03 to 0.05M cadmium was the most favorable concentration and similarly for 0.04M cadmium and MPA the optimum concentration of sulfur was 0.02M. CdS QDs optical band gap varied from 3.09 eV to 3.69 eV with quantum dots size decreasing from 3.22 nm to 2.45 nm, respectively for Cadmium concentration from 0.02M to 0.07M. For Sulfur concentration variation, band gap varied from 3.55 eV to 3.03 eV, with size of QDs increasing from 2.58 nm to 3.33 nm, respectively for concentration 0.01M to 0.05M. All this results shows that synthesized quantum dots were well under quantum confinement effect. Further, the proposed COOS method can be extended to all QDs synthesis to obtain the optimum cation to anion ratio to synthesis QDs with narrow size distribution.

High visible-light photocatalytic performance of natural hematite ore composited with ZnO nanomaterials

Xin X. Yu; Fang Z. Dong; Bao Dong; Liang Liu; Yan Wu

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 393-397
DOI: 10.5185/amlett.2017.7079

Natural hematite ore is used as a novel material for visible photocatalyst. The hematite was composited with needle-shaped ZnO via a hydrothermal approach. This hematite-based system exhibits excellent photodegradation for rhodamine (RhB) within 30 min when the hematite is hybridized with wurtzite -structured ZnO under visible light irradiation. The formation of a hybrid hetero-junction was shown by transmission electron microscope. The photocatalytic activity of the hetero-junction was evaluated by the photodegradation of RhB dye. The high photocatalytic activity observed under visible light is discussed on basis of the coupling of the hybrid hetero-junction band structure. 

Sustainability of aligned ZnO nanorods under dynamic shock-waves

M. Devika; N. Koteeswara Reddy; V. Jayaram; K. P. J. Reddy

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 398-403
DOI: 10.5185/amlett.2017.6890

In this article the sustainability of ZnO nanostructures under dynamic shock waves has been investigated. ZnO nanorods were synthesized on stainless steel (SS) substrates and exposed to shock waves in an inert atmosphere. The impact of shock waves on physical properties of ZnO nanostructures was analyzed. ZnO nanostructures grown on SS substrates exhibit excellent sustainability over different shock waves generated temperatures and pressures. The crystal structure and surface morphology of shock waves treated ZnO nanorods remain the same as untreated ones and however, the chemical stoichiometry and light emission properties are significantly changed. From these investigations it is emphasized that ZnO nanostructures could be adopted for various applications in space engineering technology where the surrounding temperature and pressure is below 8000 K and 2 MPa.

Synthesis of copper nanoparticles stabilized with cetylpyridinium chloride micelles

Nadejda N. Begletsova; Oksana A. Shinkarenko; Ekaterina I. Selifonova; Olga Yu. Tsvetkova; Andrey M. Zakharevich; Rimma K. Chernova; Aleksey A. Kletsov; Evgeny G. Glukhovskoy

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 404-409
DOI: 10.5185/amlett.2017.1423

In this paper a methodology of chemical synthesis of copper nanoparticles stabilized with surfactant cetylpyridinium chloride (CPC) micelles has been developed. By varying of the volume of a reduction agent hydrazine hydrate (HH) and value of pH of the reactionary environment the optimum conditions for synthesis of copper nanoparticles with a stable size ranging from 40 to 80 nm were found.  The copper nanoparticles obtained by this methodology have a widely perspective for use in such fields as medicine, chemistry, electronics (Langmuir-Blodgett films with conductive properties). The synthesized copper nanoparticles were characterized by scanning electron microscopy (SEM) and UV-visible spectroscopy.

Microstructural and tribological studies of Al2O3/ZrO2 nano multilayer thin films prepared by pulsed laser deposition

Balakrishnan G; Elangovan T; Shin-Sung Yoo; Dae-Eun- Kim; Kuppusami P; Venkatesh Babu R; Sastikumar D; Jung il Song

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 410-417
DOI: 10.5185/amlett.2017.6434

Nanostructured single layer aluminium oxide (Al2O3), single layer zirconium oxide (ZrO2) and the (Al2O3/ZrO2) nano multilayer films were deposited on Si (100) substrates at an optimized oxygen pressure of 3×10 -2 mbar at room temperature by pulsed laser deposition. The Al2O3 layer was kept constant at 5 nm, while ZrO2 layer thickness was varied from 5 nm to 20 nm. The X-ray diffraction (XRD) studies of single layer of Al2O3 film indicated the cubic γ-Al2O3, while the single layer of ZrO2 indicated both the monoclinic and tetragonal phases. The Al2O3/ZrO2 multilayer films of 5/5 nm and 5/10 nm indicated the tetragonal phase of ZrO2 with nanocrystalline nature. The FESEM and AFM studies showed the dense and smooth morphology of the films. The pin-on disc revealed that the 5/10 nm multilayer film has low friction coefficient ~ 0.10. The wear rate of multilayers film is half of the wear rate of the single layer films and 5/10 nm multilayer film showed a reduced wear rate when it is compared to other single and multilayers. The Al2O3-ZrO2 ceramics find wide applications in wear and corrosion resistance components, high temperature applications and bio-implant materials.

Effect of static charges on mechanical-to-electrical energy conversion of electrospun PVDF nanofiber mats

Hao Shao; Jian Fang; Hongxia Wang; Tong Lin

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 418-422
DOI: 10.5185/amlett.2017.1461

Polyvinylidene fluoride (PVDF) nanofiber mats prepared using electrospinning technique have been used for making mechanical-to-electrical energy conversion devices. However, the effect of residual charges on this energy conversion process has never been seriously considered yet. In this study, by removing residual charges from electrospun PVDF nanofiber mats using a solvent treatment method, the contribution of the charges to device energy harvesting performance was carefully examined. It has been found that isopropanol treatment could effectively remove most of residual charges from the nanofiber mats, without obviously affecting crystal structure of the fibers. The electric outputs decreased from 1.0 V and 1.2 μA to 0.45 V and 0.5 μA after the residual charges removal. It can be concluded that residue charges play an important role in mechanical-to-electrical energy conversion of electrospun nanofibers. The understanding obtained from this study may supply a strategy for enhancing electric outputs of piezoelectric devices in future. Copyright © 2017 VBRI Press.

Transient reflection spectra in topological nanocrystals of Bi2Se3, Bi2Te3, Bi2Te2Se

Faizan Ahmad; Rashmi Singh; Rachana Kumar; Mukesh Jewariya; Chandra Shekhar; Naresh Kumar; Pramod Kumar

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 423-427
DOI: 10.5185/amlett.2017.6898

The wavelength and time delay dependent reflection spectra of nano crystals Bi2Se3, Bi­2Te3 and Bi­2Te2Se were studied for ultrafast dynamics, using pump and probe spectroscopy. We observed only one transient peak for Bi2Se3 below 600nm, which decreases linearly with time delay. Three transient sharp peaks were observed for Bi2Te3 for wavelength dependent graph, which reveals about the ultrafast dynamics of charge carrier. We also observed oscillations in Bi2Se3 crystal above 600 nm which was absent in Bi2Te3 sample.  Bi2Te2Se showed a single transient spectrum peak at 482 nm with the highest peak for 103ps time delay. The curve fitted Time resolve (TR) trace for both Bi2Se3 and Bi2Te3 crystals at 492 nm wavelength, revealed almost the same results for rise and decay time. 

Mixed lipid/polymer nanostructures: From advanced materials to drug delivery systems

Natassa Pippa; Athanasios Skandalis; Costas Demetzos; Marcin Libera; Andrzej Marcinkowski; Barbara Trzebicka

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 428-434
DOI: 10.5185/amlett.2017.1414

The aim of this investigation was to study the alterations of the physicochemical characteristics of L-α-phosphatidylcholine, hydrogenated (Soy) (HSPC) and dipalmitoyl phosphatidyl choline (DPPC) liposomes, caused by the incorporation of a poly (oligoethylene glycol acrylate)-b-poly(lauryl acrylate) (POEGA-PLA) block copolymer at different molar ratios. We used Dynamic and Electrophoretic Light Scattering to determine the size and the ζ-potential; imaging techniques for investigate the structure and Static Light Scattering for quantifying the fractal morphology of the prepared nanosystems in situ. The size of mixed nanostructures became smaller with the incorporation of the block copolymer into the lipid membrane.  The size of the prepared nanosystems ranged between 50-80nm. The fractal dimension (df) decreased significantly with the incorporation of block copolymer into liposomal bilayers. The morphology of DPPC:POEGA-PLA mixed nanostructures (with df equal to 1.8) is open (more loose). On the other hand, the morphology of HSPC: POEGA-PLA (with df equal to 2.1) is more compact and dense. The molar ratio of the POEGA-PLA did not alter the morphology of the mixed nanostructures, expect from HSPC:POEGA-PLA system. Finally, we studied the drug loading properties of the mixed nanostructures in order to examine their properties as advanced Drug Delivery nanosystems. 

Synthesis and characterization of low temperature superparamagnetic cobalt ferrite nanoparticles

Kamlesh V. Chandekar; K. Mohan Kant

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 435-443
DOI: 10.5185/amlett.2017.6900

Cobalt ferrite (CoFe2O4) nanoparticles were synthesized by co-precipitation route at 80 °C. X-ray diffraction pattern (XRD) confirmed cubic inverse spinel structure of CoFe2O4 nanoparticles. The average crystallite size of CoFe2O4 nanoparticles estimated by X-ray line profile fitting was 12±2 nm for high-intensity peak (311). The particle size, distribution and surface morphology was estimated using Transmission electron microscopy (TEM) with average particle size of 16±2 nm. Raman spectra of CoFe2O4 nanoparticles exhibits phonon modes corresponding to tetrahedral sites (679 cm -1 ) and octahedral sites (465 cm -1 ) respectively. The saturation magnetization Ms for CoFe2O4 sample is found to be 63 and 82 emu/g at 300 K and 10 K respectively. The cubic magnetic anisotropy constant K1 and saturation magnetization Ms are obtained by fitting M versus H isotherm to the saturation approach law. By fitting, K1 and Ms is 2.16 x10 5 J/m 3  and 66 emu/g respectively at 300 K. The cubic magnetic anisotropy constant K1 = 5.49 x10 5  J/m 3  is evaluated at blocking temperature of 144 K. The particle size and L-S coupling is responsible for superparamagnetic behaviour of CoFe2O4 nanoparticles. Fitting of FC curve provides Curie temperature at Tc = 823K using modified Bloch’s law for CoFe2O4 nanoparticles. Tunable particle sizes by controlling the magnetic anisotropy and L-S coupling will tailor magnetic properties and usage in bio-medical applications

Titanium dioxide (TiO2) and silver/titanium dioxide (Ag/TiO2) thin films with self-cleaning properties

Ana Flávia R. Silva; Nelcy D. S. Mohallem; Marcelo M. Viana

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 444-448
DOI: 10.5185/amlett.2017.7093

In this work, TiO2 and Ag/TiO2 thin films were synthesized on glass by combination of sol-gel method and dip-coating deposition technique. Thermal treatment in temperatures ranging from 100 °C to 500 °C was used to evaluate changes in structure, morphology and texture of these materials. Adherent and microcrack-free films were obtained. The structural and morphological evolution with temperature was studied by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). Average particle size and roughness were determined by atomic force microscopy (AFM). The films were tested for wettability by measuring the contact angle between a drop of distilled water and the material surface. Results of hydrophobic/hydrophilic tests using UV-C irradiation showed that the films change their hydrophobic character to hydrophilic reaching even the superhydrophilic character which indicates their potential application as self-cleaning coatings. 

Optical properties of TiO2@C nanocomposites: Synthesized by green synthesis technique

Srikanta Karmakar; Subrata Biswas; Pathik Kumbhakar; Tapan Ganguly

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 449-457
DOI: 10.5185/amlett.2017.1421

In this work, we have reported an eco-friendly and cost-effective technique of synthesis of TiO2@Carbon nanocomposites (TCNs) material by a facile solvothermal treatment of banana (Musa balbisiana) bract extract. Yellow-green photoluminescence (PL) feature and efficient catalytic activities of green synthesized TCNs have been demonstrated. X-ray diffraction (XRD) data has revealed the simultaneous presence of rutile and anatase phases of TiO2 in the synthesized TCNs. The presence of amorphous carbon and TiO2 is also confirmed by Raman spectroscopy. The light emission characteristics of TCNs are studied by PL emission spectroscopy which has confirmed the presence of defect levels caused by oxygen vacancies and surface hydroxyl groups localized within the band-gap. The photocatalytic performance of the synthesized material has been systematically evaluated by observing the degradation of Methylene Blue (MB) dye under the incidence of ultraviolet-visible (UV-Vis)/visible light irradiation and manifested a superior UV-Vis light photo-catalytic activity far over the commercial TiO2 powder (CTP) under the same experimental conditions. A relatively higher electrochemical performance and 52 times larger cathodic current density is obtained in TCNs in compared to that of CTP. TCNs exhibit extremely high hydrogen evolution reaction catalytic activity with very small onset over potential.

Effect of charge transfer band on luminescence properties of Yb doped Y2O3 nanoparticles

Pratik Deshmukh; S. Satapathy; Anju Ahlawat; Khemchand Sahoo; P. K. Gupta

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 458-464
DOI: 10.5185/amlett.2017.6560

The photoluminescence properties of Yb doped Y2O3 nanoparticles were investigated in visible region to resolve the origin of dissimilar fluorescence peaks at different excited wavelengths and to explore possible use of Yb: Y2O3 for white light emission, excited by available near UV LED. The peak observed at 370 nm in photoluminescence excitation spectrum is due to expected transition of electrons from 2 F7/2 to charge transfer band (CTB) associated with non-centrosymmetric C2 centers however, the excitation peak at 335 nm is due to transition of electrons from 2 F7/2 to the CTB associated with distorted centrosymmetric C3i centers. The Yb doping in nano Y2O3 not only modify the CTB but also helps in transition of electron from these CTBs to ground 2 F5/2 and 2 F7/2 levels of Yb. Strong broad emission peak is observed at 503 nm which is assigned to transition from distorted CTB (C3i) to 2 F5/2 energy levels. The findings are important because broad emission (from ~400 to ~650 nm) at 335 nm excitation (available AlGaN LED wavelength) due to C2 and C3i centers in Yb: Y2O3 may be used for white light emission applications.

Ionic conductivity enhancement studies of composite polymer electrolyte based on poly (vinyl alcohol)-lithium perchlorate-titanium oxide

Chin-Shen. Lim; K. H. Teoh; H. M. Ng; Chiam-Wen Liew; S. Ramesh

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 465-471
DOI: 10.5185/amlett.2017.1410

In this study, poly (vinyl alcohol) (PVA), lithium perchlorate (LiClO4) and nano-sized titanium oxide (TiO2) were employed as host polymer, dopant salt and inorganic filler respectively. The influence of the inorganic filler on ionic conductivity, structural and morphological properties of the polymer matrix are investigated. Ionic conductivity of polymer electrolytes is measured by ac-impedance spectroscopy at ambient temperature. The polymer electrolyte exhibits the highest ionic conductivity of 1.26×10 -4 S cm -1 upon addition of 8 wt. % TiO2. Dielectric behavior proves that incorporation of nano-sized TiO2 particles shows a significant effect on the dielectric constant of the polymer electrolyte system. XRD analyses disclose that the addition of TiO2 reduces the crystallinity of the polymer electrolytes which enhances the flexibility of polymer chains. 

Streptavidin conjugated ZnO nanoparticles for early detection of HIV infection

L. A. Avinash Chunduri; Aditya Kurdekar; Bulagonda Eswarappa Pradeep; Mohan Kumar Haleyurgirisetty; Venkataramaniah K; Indira K. Hewlett

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 472-480
DOI: 10.5185/amlett.2017.6579

Streptavidin labelled fluorescent ZnO nanoparticles have been surface engineered to develop a fluorescent ZnO nanoparticle linked immunoassay (FZLIA) for the sensitive detection of HIV infection. ZnO nanoparticles were synthesized by a single step chemical precipitation method. Cysteine was used to graft carboxyl groups on to the surface of nanoparticles in a single step. Cysteine capped ZnO nanoparticles exhibited fluorescence at 546 nm when excited with 358 nm and FESEM confirmed the particle size to be 50-70 nm. FTIR and TGA confirmed the functionalisation of carboxyl groups by cysteine. The amount of cysteine grafted on the ZnO nanoparticles calculated as 68.1% from TGA analysis indicated the presence of large amount of carboxyl groups. ZnO nanoparticles were conjugated to streptavidin and the same were deployed as fluorescent probes in the development of the FZLIA platform for the early and accurate detection of HIV infection. The linear dose dependent detection range was from 25 pg/mL to 1000 pg/mL. HIV positive and HIV negative plasma samples were tested using FZLIA for the presence of HIV-1 p24 antigen. This immunoassay exhibited no false positive and false negative results with the clinical samples tested. This highly sensitive HIV-1 p24 antigen assay may be useful to improve blood safety by reducing the antibody negative window period in blood donors in resource limited settings where nucleic acid testing is not practical or feasible. This technology can be transferred to a lab-on-chip platform for use in resource limited settings and can also be easily adopted for the detection of other antigens.

Transport properties of blended cement based on dredged sediment and shells

Hassan Ez-zaki; Abdeljebbar Diouri; Siham Kamali-Bernard

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 481-485
DOI: 10.5185/amlett.2017.1434

This paper reports an experimental study carried out to investigate the influence of dredged sediments and shell powders on the transport properties of mortar. Blend based on the combination of marine by-products was used to replace a part of Portland cement, after thermal treatment. Cylindrical mortars and pastes were cast with water to binder ratio of 0.5 and 0.4, respectively. Control specimens were also cast. After 28 days of curing in water, the apparent porosity, the gas permeability, the chloride diffusion and accelerated carbonation was investigated. The results showed that the combination of dredged sediment and shell powder provides a positive effect on the transport properties. Besides, mortars containing 33% by weight of blend showed low gas permeability than that of the control mortar even apparent porosity is higher. In addition, the resistance to the chloride ingress is more pronounced for mortars with sediment:shell blend. The carbonation thickness is related to the carbonation age and replacement level. This blend proved better transport properties by the filler effect.

Electronic excitation induced modifications of nanostructured Ni-Ti shape memory alloy thin films

V. Kumar; R. Singhal; R. Vishnoi; M. Gupta; P. Sharma; M. K. Banerjee; K. Asokan; H. Sharma; A. Gupta; D. Kanjilal

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 486-492
DOI: 10.5185/amlett.2017.6211

In the present work, the effects of 120 MeV Au ion irradiation at different fluences ranging from 1×10 12 to 3×10 13 ions/cm 2 on structural and electrical properties of thin films of Nickel-titanium (Ni-Ti) shape memory alloys (SMAs) grown on Si substrate using DC magnetron co-sputtering is studied. The surface morphology, crystallization and phase transformation behaviour of these films were investigated using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Four-terminal resistivity measurement method. XRD pattern reveals that both the phases-martensite as well as austenite exist in the pristine film. Resistivity measurements revealed a two way transformation from cubic to rhombohedral and from rhombohedral to monoclinic phase in pristine film and decrease in its transformation temperature with increased fluence. At higher fluences 5×10 12 and 1×10 13 ions/cm 2 , films showed non-metallic behaviour which could be due to the disorder occurring in these films due to ion impact and precipitate formation. The elemental composition of pristine film is determined by Rutherford backscattering spectroscopy. 

Twining ZnO nanoparticles to nanorods with control growth and size-shape dependent interactions with cancer cells: Role of physical properties and cell inhibition

Vijay Bhooshan Kumar; Pradip Paik

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 493-499
DOI: 10.5185/amlett.2017.6474

In this work, we reported the control size and shape dependent cellular interactions of ZnO nanoparticles ranging from tiny nanodisks to nanorods, with carcinoma cells. These particles were synthesized through the wet chemical synthesis approach. Size and shape of the ZnO nanoparticles were tuned by varying the concentration of Igapal CO50. Size and shape dependent interactions were investigated with human carcinoma cells (K562, a Leukaemia Cancer Cells) without attaching any anticancer drugs and the results manifest that the size, shape and physical properties of ZnO nanoparticles are preferentially the critical factors in interactions and killing the cancer cells when no anticancer drugs were used. ZnO nanoparticles are used of aspect ratio from 1.3 to 5.5. Interaction and killing of carcinoma cells depend on the extent of defects and on the electro paramagnetic behavior of the ZnO nanoparticles. Further, Raman and EPR studies revealed that the size dependent phonon localization of oxygen defects of ZnO control the formation of singlet oxygen on interactions with cancer cells and regulate the anticancer effects of ZnO nanoparticles even in the absence of drugs. ZnO NPs with low aspect ratio is more vigorous in killing the carcinoma cells.

Single- and multi-layered porous titanium via metal injection moulding

Mohammed Menhal Shbeh; Russell Goodall

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 500-505
DOI: 10.5185/amlett.2017.7052

Titanium foams are advanced materials with macroporous structure that have a great potential in a variety of areas such as biomedical and functional applications. They are characterized by their reduced density and stiffness, with high permeability and excellent biocompatibility. One production technique for Ti foams with promising results is Metal Injection Moulding (MIM). So far most of the porous titanium produced by this technique has a very basic design with low percentage of porosity, thus limiting its potential in the biomedical industry, among others. In this study, the use of MIM in combination with a space holder to produce single and multi-layered porous Ti with high volume percentage of porosity will be explored. The results show that it is possible to produce Ti foam with a total volume percentage of porosity of 61 % through MIM technology. In addition, it is also feasible to combine different porous layers resulting in multi-layered porous titanium parts with gradient porosity that could have a huge potential in a wide range of applications, especially for biomedical implants, where these pores can promote bone ingrowth as well as reduce stiffness to match that of the natural bone, thus alleviating the stress shielding problem.

Low viscosity, stable TiO2 nano-fluid for oxidative photo-degradation of methylene blue

Ujjwal K Bhagat; Anuraj S. Kshirsagar; Ashish Gautam; Pawan K Khanna

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 506-517
DOI: 10.5185/amlett.2017.6960

The present article highlights a simple and effective method for preparation of nano-fluid (NF) by employing long carbon chain fatty acid, PVP and ethylene glycol stabilized anatase phase TiO2. The so-prepared nano-fluid (0.5 wt. %) was employed for advanced oxidative photo-degradation of MB with different concentrations (1-5 mL) under short (254 nm) and long UV (365 nm) irradiation against various concentrations (5, 15, 25 ppm).  The maximum degradation efficiency observed was 88% and 71% under short and long UV irradiation respectively. The photocatalytic degradation of the MB was also studied by reaction kinetics.  Initially, titania nanoparticles (NPs) were synthesized and characterized using various advanced tools such as UV-Visible, FTIR, Raman spectroscopy, BET, XRD, SEM/EDAX, TEM etc. for its size, surface area and morphological understanding.

Nanostructured carbon materials for hydrogen energetics

Peteris Lesnicenoks; Liga Grinberga; Laimonis Jekabsons; Andris Antuzevičš; Astrida Berzina; Maris Knite; Gatis Taurins; Šarūnas Varnagiris; Janis Kleperis ​

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 518-523
DOI: 10.5185/amlett.2017.7088

Hydrogen storage is one of the main problems, to catalyse wide hydrogen use in transportation, technology and energetics. Composites involving nanostructured carbon species could be the solution for hydrogen storage problem because of their promising surface/volume relation. Not only catalysis and gas sensing on graphene basis should be considered, but also metal decorated graphene structures for use in hydrogen storage should be an active field for research and development. Heat conductivity and large surface area of graphene-like materials can endorse research for hydrogen storage in low pressures and close to room temperature (RT) conditions - increasing possibility for RT-range devices in hydrogen energetics. For increased hydrogen storage investigations, we propose metal intercalated graphene structures, acquired during synthesis of graphene sheets. Intercalation, or decoration of graphene surfaces and edges have shown possibility to stabilize defects in graphene sheets. Graphene defects have shown to be sensitive against hydrogen gas and might as well prove themselves stable enough to achieve low pressure hydrogen storage. A simple method is proposed for synthesis of graphene sheet stacks (GSS). There is lack of research for synthesis of carbon nanomaterials from industrial graphite waste. Our research for stabilization of electrolyte solution and increased production amounts for hydrogen accepting samples continues.

Synthesis of Cu doped ZnO nanorods for photosensitive UV detection application

S. N. Sarangi; V. Siva; B. K. Padhi; P. K. Sahoo

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 524-530
DOI: 10.5185/amlett.2017.7022

We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to confirm the doping of Cu in ZnO nanorods. The PIXE measurements confirm the absence of any foreign element in parts per million level, except pure Cu doping in ZnO. The compressive stress in (002) peak develops after Cu doping is indicating the successful substitution of Cu +2 ions into Zn +2 lattice sites. The I-V measurement of 5% Cu doped ZnO device shows five orders of magnitude increase in current flow compared to 1% Cu doping.  Under ultraviolet (UV) light exposure further enhancement of the photocurrent in the devices has been observed, which demonstrates the capability of Cu doped ZnO nanorods as a potential UV photodetector. 

Electrochemical nanobiosensor for real-time detection of gap junction-mediated intercellular communication activity

Halina V. Grushevskaya; Nina G. Krylova; Igor V. Lipnevich; Taisija I. Orekhovskaja; Boris G. Shulitski

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 531-541
DOI: 10.5185/amlett.2017.7092

A capacitive nanobiosensor which consists of multiwalled carbon nanotubes (MWCNTs) covered by conducting oligomer of thiophene-pyrrole derivatives was constructed and fabricated to detect the gap junction-mediated communication between living cells in a monolayer. The sensor operates on screening and spin-dependent polarization effects in nanoheterostructures which present themselves MWCNTs decorated by organometallic complexes of high-spin Fe(II) and are fabricated by a Langmuir-Blodgett (LB) technique. The nanoheterostructures were deposited on transducer, which is an interdigital electrode system covered by a dielectric layer. As the cell monolayer density increased while the cells proliferated on the sensor surface, the sensor capacity decreased until the cell monolayer was confluent. This decrement is due to a forming network of the open gap junction channels (GJCs) in accordance with an electrochemical analysis performed. The monolayer capacity increases when adding GJC inhibitor (carbenoxolone) which leads to decrease of a number of the open GJCs. The technique has been used in real-time regime to establish some principles of menadione-mediated GJC-network fine-tuning. Menadione causes Ca 2+ -dependent GJ channels opening/closing.

ZnO sol-gel oxide coatings as materials for UV optical filters

Karolina Moszak; Anna Szczurek; Bartosz Babiarczuk; Beata Borak; Justyna Krzak

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 542-545
DOI: 10.5185/amlett.2017.7108

Ultraviolet light influences materials structure causing the decomposition and degradation of organic compounds. One of the ideas to reduce the harmful effects of light is to protect materials by sol-gel coatings. ZnO sol-gel thin films on a glass substrate were obtained as optical filters. The filter effect of synthesized coatings stabilized in different temperatures were characterized by UV-Vis transmittance spectroscopy. The morphology and elemental composition of coating surface was determined by SEM and EDX. Scratch resistance and adhesion have been evaluated by scratch test. The coatings present high transparency in the visible region and absorption in the UV region (270-360 nm). The results suggest that the obtained materials have proper parameters for UV optical filters. 

Gamma irradiation synthesis and in vitro drug release studies of ZnO/PVA hydrogel nanocomposites

Swaroop Kumaraswamy; Gangadhar Babaladimath; Vishalakshi Badalamoole; Somashekarappa H Mallaiah

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 546-552
DOI: 10.5185/amlett.2017.6819

In the present work, the synthesis of ZnO/PVA hydrogel nanocomposites was carried out using the gamma irradiation technique. The ZnO nanoparticles were synthesized using co-precipitation method and dispersed in the PVA solution. To prepare the ZnO/PVA hydrogel nanocomposites, the mixture was exposed to gamma irradiation dose of 25 kGy. The formation of ZnO nanoparticles in PVA matrix was confirmed using the powder X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and the UV-Visible Spectrophotometer (UV). The surface morphology of the hydrogels was studied using the Field Emission Scanning Electron Microscopy (FESEM). The swelling ratio and equilibrium degree of swelling (% EDS) were evaluated and there was drastic reduction in swelling and % EDS with the addition of ZnO nanoparticles to the PVA mixture. The l-ascorbic acid was loaded to the hydrogels and the release data was monitored by the absorption wavelength at 252 nm using UV. The drug release data was fitted to zero order, first order, Higuchi’s model, and Korsmeyer-Peppas’s model for the detailed analysis. The results suggest that ascorbic acid release from the hydrogel matrix follows the non-Fickian mechanism. 

Influence of anodization parameters on topographic and morphological properties of TiO2 nanotube arrays: A reconstruction from SEM measurements

A. Dussan; Heiddy P. Quiroz

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 553-556
DOI: 10.5185/amlett.2017.7109

In this work, we fabricated samples of titanium dioxide nanotube arrays via electrochemical anodization by using titanium foils as anode and cathode. A solution of water, ethyleneglycol, and ammonium fluoride (NH4F) at room temperature was used for the samples synthesis process. Different times and anodizing voltages were used during reaction. From X-ray diffraction (XRD) and micro-diffraction (mXRD) measurements, rutile and anatase phases were identified as function of deposition parameters. The Ti3O5 phase was observed by deconvolution of Debye-Scherrer rings of the microdiffraction spectra. Annealing processes were performed for all samples in the range between 273 and 723 K, without changes in the material’s morphological properties, while the crystalline structure was affected. Nanotube diameters varying between 30 and 42 nm were observed from SEM micrographs, when NH4F concentration was changed from 0.25 to 0.50 wt%. An alternating anodizing voltage generates the formation of nanotubes evenly spaced on the surface with nodes in bamboo-type form, while a smooth form for nanotubes was observed with constant applied voltage. From stereoscopic 3D micrographs, a reconstruction of the topographic surface of the TiO2 nanotubes was conducted. A correlation between synthesis parameters and morphological properties is presented. 

Synthesis and photoluminescence study on europium ion activated titania nanoparticle

Thoudam Nando Singhi; Thongam Gomti Devi; Shougaijam Dorendrajit Singh

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 557-564
DOI: 10.5185/amlett.2017.1432

Eu 3+ doped TiO2 (0.2-1at. %) is synthesized successfully by non-aqueous sol-gel technique at low temperature. They are characterized structurally and optically with the used of X-ray diffraction (XRD), UV-visible spectrophotometer, Photoluminescence (PL), microscopy (SEM) and Transmission electron microscopy (TEM). The anatine toretile phase transition is observed at 750 o C and lattice distortion ratios are reduced whereas crystallites sizes are found to increase with increases of temperature. The emission spectrum under excitation at the 7 F0→ 5 L6 (393nm) transition of the Eu 3+ ion shows broad emission bands arising from the 5 DJ (J=0, 1) levels and with the emission decays lifetime varying between 0.243 and 0.375ms for samples prepared at different temperatures. The Judd-Ofelt intensity parameters W2 are found in the range 6.57 - 17.14 x10 -20 cm 2 at different concentrations and temperatures. Quantum yield of all the samples are more than 80% at different temperature. The average decay lifetime decreases with the increase of Eu 3+ concentration. 

Influence of oxygen ions irradiation on the optical properties of photoanodes for dye sensitized solar cell

Amrik Singh; Devendra Mohan; Dharmavir S. Ahlawat; Sandeep Chopra

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 565-571
DOI: 10.5185/amlett.2017.6518

Indium Tin Oxide (ITO) coated glass acts as a substrate for photoanode of Dye Sensitized Solar Cells (DSSCs). The ITO substrate was irradiated by oxygen ion with different fluence (1x10 11 and 1x10 12 ions/cm 2 ) at 100 MeV energy. The TiO2 films were also subjected with same ion irradiation at 100 MeV of energy with fluence of 1x10 11 ions/cm 2 and 5x10 12 ions/cm 2 . At 100 MeV energy of O 7+ ion the electronic and nuclear energy loss for TiO2 film have been measured 7.38x10 -1 KeV/nm and 3.8x10 -4 KeV/nm respectively.  However, the electronic and nuclear energy loss of ion irradiation for ITO substrate were 7.4x10 -1 KeV/nm and 4.06x10 -4 KeV/nm respectively. Similarly longitudinal/ lateral straggling of ITO and TiO2 have been found 3.87 μm/2.50 µm and 3.62 µm/1.14 μm respectively. Further, the structural and optical properties of these samples were monitored by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible spectroscopy. It was found that oxygen ion (O 7+ ) irradiation of ITO film has slightly changed the crystallinity and transmission decreases. Furthermore, the particle size of TiO2 thin film has been obtained 80 nm corresponding to (101) plane of XRD pattern. In the case of ITO thin film the crystallite size and band gap changes from 62.35 nm to 53.89 nm and 3.993 eV to 3.971 eV at 1x10 12 ions/cm 2 respectively. Moreover this paper is also reporting that irradiation by swift heavy ion has changed the transmission of the ITO films, and its values decreases as compared to pristine (ITO) which degraded the performance of DSSC. Consequently, a very small value of absorbance is reported for ITO film. However, the absorbance of TiO2 film has found to increase with irradiation of oxygen ion at fluence of 1x10 12 ions/cm 2 and decreased at 5x10 12 ions/cm 2 . It is also confirmed that the absorbance of TiO2 film and TiO2/ITO photoanode increases with irradiation of oxygen ion at fluence of 1x10 12 ions/cm 2 and decreased at 5x10 12 ions/cm 2 .  The band gap values of TiO2 thin film were obtained to have a change from 3.37 eV (for pristine) to 3.44 eV at 5x10 12 ions/cm 2 . But the decrease in band gap is also found 3.17 eV at fluence of 1x10 12 ions/cm 2 . However, N719 dye loaded O 7+ (1x10 12 ions/cm 2 ) irradiated TiO2 film show high absorption as compared to other samples. Thus the dose of O 7+ irradiation at fluence 1x10 12 ions/cm 2 may fabricate more efficient DSSC and consequently future prospective of such type of photoanode materials for dye sensitized solar cells seems to be bright.

Electrochemcial sensing of anti-diabetic drug using hierarchically deposited PB nanocubes on carbon nanospheres layered on transparent glass electrode

Jagriti Narang; Chaitali Singhal; Vibhor Kaushal; C. S. Pundir

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 572-576
DOI: 10.5185/amlett.2017.7041

Prussian Blue nanocubes / carbon nanospheres (PB-CNS) heterostructure composed of perfectly cube and spherical composite on indium tin oxide (ITO) surface were developed for in vitro sensing of anti-diabetic drug i.e. Sitagliptin (STA). Detailed morphological, electrochemical, structural and optical characterization of PB-CNS/ITO electrode was done using DLS, SEM, EIS, CV. The sensor showed rapid response time (within 5 s) and the linear range from 0.001 to 10 mM with a shelf life of about 10 weeks under refrigerated conditions. We have also attempted to employ this electrode for assessment of STA in urine samples. The developed sensor exhibited high reproducibility and good storage stability.