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Zinc(II) 8-hydroxyquinoline (Znq2) green luminescent material and its blended thin film in a poly(methyl methacrylate) (PMMA) matrix have been prepared. XRD analysis confirms the formation of the compound and its presence in the PMMA blended thin film. The orbital molecular geometry, quantum chemical calculations and band gap energy of Znq2 phosphor have been confirmed from the DFT study. The morphology of the phosphor was shown by the SEM images. UV–Vis absorption, photoluminescence and decay analysis of zinc(II) 8-hydroxyquinoline phosphor confirms its suitability as a green emitter for organic light-emitting diodes. Uniform distribution of Znq2 powder in the PMMA matrix and its roughness was estimated by AFM analysis. Luminescence decay study was utilized to demonstrate its lifetime analysis by the time-correlated single-photon counting (TCSPC) system.

Polymer solar cells (PSCs) based on binary and ternary active layers were built using PBDB-T polymer as donor and two non-fullerene acceptors (MPU2 and MPU3) with different DPP cores and terminal units but different conjugation length. The studied binary PSCs showed PCE (power conversion efficiency) values of 8.22% (PBDB-T:MPU2) and 9.77% (PBDB-T:MPU3). The VOC measured using the MPU3-based acceptor was higher than that obtained using MPU2 – this difference is attributed to a higher LUMO energy level of MPU3. MPU2 and MPU3 present complementary absorptions in the wavelength range where PBDB-T exhibits a poor absorption, thus the combination of these materials offers great potential for the fabrication of ternary PSCs. The solar cell with an optimized ternary layer PBDB-T:MPU2:MPU3 (1:1:1) showed an PCE value of 10.78%, higher than those obtained for the binary devices due to the enhanced of JSC and FF values. And, since the emission of MPU3 partially overlaps with the absorption of MPU2, the transfer of energy from MPU3 to MPU2 can improve the exciton utilization efficiency and achieve enhanced overall power conversion efficiency in this ternary solar cell.

In the present study, crystallization of amorphous-Si (a-Si) in Al/a-Si bilayer thin films under thermal annealing and ion irradiation has been investigated for future solar energy materials applications. In particular, the effect of thickness ratio (e.g. in Al : a-Si, the ratio of the Al and a-Si layer thickness) and temperature during irradiation on crystallization of the Si films has been explored for the first time. Two sets of samples with thickness ratio 1 : 1 (set-A: 50 nm Al/50 nm a-Si) and thickness ratio 1 : 3 (set-B: 50 nm Al/150 nm a-Si) have been prepared on thermally oxidized Si-substrates. In one experiment, thermal annealing of the as-prepared sample (of both the sets) has been done at different temperatures of 100 °C, 200 °C, 300 °C, 400 °C, and 500 °C. Significant crystallization was found to initiate at 200 °C with the help of thermal annealing, which increased further by increasing the temperature. In another experiment, ion irradiation on both sets of samples has been carried out at 100 °C and 200 °C using 100 MeV Ni7+ ions with fluences of 1 × 1012 ions per cm2, 5 × 1012 ions per cm2, 1 × 1013 ions per cm2, and 5 × 1013 ions per cm2. Significant crystallization of Si was observed at a remarkably low temperature of 100 °C under ion irradiation. The samples irradiated at 100 °C show better crystallization than the samples irradiated at 200 °C. The maximum crystallization of a-Si has been observed at a fluence of 1 × 1012 ions per cm2, which was found to decrease with increasing ion fluence at both temperatures (i.e. 100 °C & 200 °C). The crystallization of a-Si is found to be better for set-B samples as compared to set-A samples at all the fluences and irradiation temperatures. The present work is aimed at developing the understanding of the crystallization process, which may have significant advantages for designing crystalline layers at lower temperature using appropriate masks for irradiation at the desired location. The detailed mechanisms behind all the above observations are discussed in this paper.

C60/Ag/Au multilayer thin films are synthesized on glass substrate by thermal co-deposition method followed by ion irradiation by high energy ion beam of 120 MeV Au ions using Pelletron accelerator. The effect of ion irradiation by 120 MeV Au ions on the optical and structural properties of the synthesized multilayer thin film samples at different fluences ranging from 6 × 1012 to 3 × 1013 ion/cm2 is investigated. By UV–visible spectroscopy, optical studies of pristine and Au ion irradiated samples are examined. Surface Plasmon Resonance (SPR) peaks of Au and Ag nanoparticles are obtained at wavelength ∼687 nm and ∼628 nm, respectively after irradiation at a fluence of 3 × 1013 ions/cm2. Atomic force microscopy was performed to analyze the surface morphology after irradiation. Due to ion irradiation, overall roughness estimated to be increased with increasing fluence. TEM revealed the growth of metal nanoparticles in size due to agglomeration after irradiation. I–V measurements are preformed to study the electrical properties after irradiation with 120 MeV Au ion.

Bi-functional nanocomposite thin films of fullerene C60 and C70 containing Au NPs were synthesized using thermal co-evaporation method. Different atomic concentrations of Au metal varying from 5 to 35 at.% was chosen to get the Au NPs with different sizes in fullerene matrix. The thickness of films and metal concentration is confirmed by Rutherford backscattering spectroscopy (RBS). UV-visible spectrum shows the excitation of SPR band in all samples except for the lowest metal concentration which is ~ 5 at.% and SPR is red shifted with increasing concentration of Au. The shift in SPR position with increasing metal concentration for both Au-C60 and Au-C70 is nearly linear. X-ray diffraction spectroscopy indicates the formation of bigger size particles with increasing metal concentration in both the cases of Au-C60 and Au-C70, which is further confirmed by transmission electron microscopy results. Au-C60 and Au-C70 (could) be interesting nanocomposites for surface-enhanced Raman scattering studies.

The aim of this work was to develop the better combination of CoFe2O4 (CFO) and BaTiO3 (BTO) nanoparticles with enhanced dielectric properties. For this purpose, CFO/BTO nanocomposites at (0, 20, 40, 60, 80, and 100) wt% were synthesized using solid state method. The structural, optical and dielectric properties were investigated using the X-ray diffractometer, UV–Vis spectroscopy, and LCR meter respectively. The crystallite sizes of CFO and BTO were found to be 5.6 nm and 36.2 nm, respectively, by Scherrer’s formula. The uniform and nonuniform strains were determined using Hall method. The absorption edge and energy band gap were estimated from UV-B to visible range. The FESEM and EDX were used to confirm the crystallite size and pure formation of CFO/BTO nanocomposites with different concentration of BTO. The dielectric constant, dissipation factor and activation energy were observed higher for 20 wt% BTO as compared with other wt%, which is optimum combination of CFO/BTO nanocomposites.

In this work, the thin films of vanadium oxide on Si substrate were deposited by RF sputtering and pulsed laser deposition method. The as-deposited samples were annealed in argon atmosphere at 500°...

Cu-C70 nanocomposite thin film is synthesized via thermal co-evaporation method. The atomic concentration of Cu in the thin film is found to be ~4.5 at.% using Rutherford backscattering spectroscopy. Sequential thermal annealing is performed in an inert atmosphere (in presence of Ar) at various temperatures. Surface plasmon resonance (SPR) is spotted at ~585 nm for the sample annealed at 300 °C and the SPR peak is shifted towards ~621 nm for the sample annealed at 400 °C. In order to determine the modifications arising in the structure of fullerene C70 matrix due to annealing, Raman spectroscopy is used. At the highest temperature of 400 °C, the high-intensity Raman active modes of fullerene C70 can still be observed which shows that fullerene C70 is not completely transformed into amorphous carbon upto this temperature. Transmission electron microscopy is performed to determine the size of particles which is obtained ~35 nm for the sample annealed at 400 °C. The red shift in SPR wavelength at 400 °C is ascribed to the growth of Cu nanoparticles.

Copper metal embedded fullerene C60 thin films are deposited on various substrates via resistive heating co evaporation technique. Rutherford back scattering simulated spectrum confirms the thickness and composition of thin film to be ~ 32 nm and ~ 18 at%, respectively. The deposited thin films are irradiated by 120 MeV Ag ion beam for different fluences within the range, from 1 × 1012 to 3 × 1013 ions/cm2. UV–vis absorption spectroscopy study reveals the appearance of surface plasmon resonance (SPR) band in pristine thin film at ~ 622 nm; this phenomenon is ascribed to the presence of copper nanoparticles in C60 matrix. The SPR band intensity increases with rising fluences, which is suggestive of the growth of Cu nanoparticles. Growth of Cu nanoparticles is further confirmed by transmission electron microscopic (TEM) and X-ray diffraction (XRD) study. Whereas the conversion of C60 into amorphous carbon (a-C) is confirmed by Raman spectroscopy, XRD results of pristine Cu–C60 thin film record the presence of Cu2O within the nanocomposite thin film. However, both X-ray photoelectron spectroscopy (XPS) and XRD studies on irradiated thin film samples authenticate the growth of Cu metal nanoparticles with concurrent removal of oxygen.

Low energy ion irradiation is an interesting tool to accomplish the bulk modifications of different materials. The impact of low energy ion bombardment is studied on Cu-C70 nanocomposite thin films prepared by thermal co-deposition technique. A beam of 180 keV Ar ions was used for this purpose which results in a drastic change in structural, optical and electrical properties. It is demonstrated that surface plasmon resonance (SPR) was successfully induced with ion irradiation initially at a fluence of 3 × 1014 ions cm−2 and is observed to be first red shifted and then blue shifted on increasing fluence of ion irradiation. The results of Raman spectroscopy reveal the progressive transformation of fullerene C70 into amorphous carbon with increasing fluence. The I(D)/I(G) ratio is calculated to analyze amorphous carbon and improved ordering of amorphous carbon at higher fluences is observed. TEM images verified the continuous growth of copper nanoparticles subjected to low energy ion irradiation with increasing fluence which is ascribed to the agglomeration of particles as pointed by EDS mapping images. FTIR results show that the destruction of fullerene C70 matrix is initiated at a fluence of 3 × 1014 ions cm−2, which coincides with the appearance of SPR band. The transformation of fullerene into amorphous carbon and the growth of copper nanoparticles was found to be responsible for increase in conductivity with fluences as confirmed by I-V measurements.

Two D–A–D small molecules with a DPP acceptor core and Zn-porphyrin donor with different electron-donating substituents, namely, 2,6-bis(dodecyloxy)phenyl and 5-hexylthieno[3,2-b]thiophen-2-yl at mesopositions, VC4 and VC5, were synthesized, and their optical and electrochemical properties were investigated. The results reveal that both molecules are suitable as donors for organic solar cells (OSCs) in which PC71BM is employed as the acceptor. Overall power conversion efficiencies of 8.05% (Jsc = 13.83 mA/cm2, Voc = 0.91 V, and FF = 0.64) and 8.89% (Jsc = 16.98 mA/cm2, Voc = 0.79 V, and FF = 0.663) were obtained, respectively. The high Voc value for the VC4-based OSC correlates with the deeper HOMO, whereas the high Jsc value for VC5 may be attributed to the extended absorption spectrum toward the longer wavelength region. Moreover, the relatively high FF value for VC5-based OSCs as compared to the VC4 counterparts may be related to the more balanced charge transport in the active layer, reduced charge re...

Nanocomposite of fullerene C70 embedded with Cu nanoparticles is synthesized using thermal co-deposition method. The temperature dependency of SPR and size of Cu nanoparticles are assessed by thermal annealing in inert atmosphere up to a temperature of 350 °C. Rutherford backscattering spectroscopy is performed to assess the thickness of the film and the atomic fraction of Cu metal. The UV-visible absorption spectra on as-deposited and annealed samples reveal that the SPR peak of Cu nanoparticles appears at 300 °C and its evolution with further rise in temperature takes place with a red shift and broadening of the peak at 350 °C. The thermal induced growth of Cu nanoparticles at higher temperature is responsible for the red shift. Raman spectra show the decrease in the intensity of vibrational modes of fullerene C70 with temperature due to breaking of bonds among carbon atoms in fullerene molecules. Transmission electron microscopy confirms the evolution of Cu nanoparticles with bi-modal distribution at 350 °C. Atomic force microscopy is performed to observe the variation in the morphology and roughness of nanocomposite film with temperature. The evolution of Cu nanoparticles and excitation of SPR with temperature makes it an interesting nanocomposite for SPR sensing applications.

We have designed an A–π–D–π–A small-molecule triad consisting of a bacteriochlorin (BC) donor central core linked with two diketopyrrolopyrrole (DPP) acceptors via ethynyl bridges (BC-DPP-1). BC-DPP-1 has a narrow optical bandgap of 1.38 eV with highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of −4.93 eV and −3.40 eV, respectively, and it was used as an electron donor along with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an acceptor for solution-processed small-molecule organic solar cells. After optimizing the weight ratio between BC-DPP-1 and PC71BM and pyridine as a solvent additive and subsequent solvent vapor annealing using THF, an organic solar cell based on the optimized BC-DPP-1:PC71BM showed an overall power conversion efficiency of 7.48%. Since BC-DPP-1 shows a weak absorption band in the 650–750 nm wavelength region, we used a second small molecule having strong absorption in this spectral region and prepared the ternary active layer BC-DPP-1 : SM : PC71BM, varying the weight ratio between the two donors and keeping the amount of PC71BM constant. The ternary active layer BC-DPP-1 (70% w/w):SM (30% w/w):PC71BM showed the best photovoltaic performance. After the optimization of the ternary active layer (i.e., the solvent additive and subsequent solvent vapor additive), the organic solar cell showed overall power conversion efficiency of 9.88%. The improved power conversion efficiency resulted from the enhancement of Jsc, Voc and FF as compared to the binary counterpart. Since BC is an analog of porphyrins and chlorophylls, these results demonstrate that benefiting from the narrow band gap of BC-DPP-1 (i.e., organic solar cells with light harvesting in the NIR region of the solar spectrum) can be a real improvement. Moreover, the low energy loss (0.48 eV) as compared to the binary counterpart (0.58 eV) also confirms the suppressed recombination in the ternary organic solar cells.

Plasmonic nanocomposite thin film containing Cu metal nanoparticles in fullerene C60 matrix is developed by thermal co-evaporation method on glass substrate. In order to excite the surface plasmon resonance (SPR), thermal annealing is performed from 100 °C to 400 °C on as-deposited thin film in an inert atmosphere (continuous flow of Ar gas) for 30 min. SPR is successfully generated at ∼694 nm for the film annealed at a temperature of 300 °C which is further blue shifted at ∼684 nm at a temperature of 400 °C. The film thickness and Cu metal atomic concentration is found to be ∼70 nm and ∼27 at.%, respectively using Rutherford Backscattering Spectroscopy. Raman spectroscopy is used to identify the structural changes occurring in fullerene C60 matrix with thermal annealing. The transformation of fullerene C60 into amorphous carbon is observed with increasing temperature. Transmission electron microscopy is used to confirm the growth of Cu nanoparticles with increasing temperature and particle size is found to be 27.9 nm for the film annealed at 400 °C. The modifications in surface morphology of annealed samples are studied by field emission electron microscope (FE-SEM) and atomic force microscope (AFM). The absence of Copper oxide in the annealed samples is confirmed by X-ray photoelectron spectroscopy. Current vs. voltage measurements are performed to quantify the increased conductivity of annealed samples.

The effect of 220 keV Ag ion beam irradiation on the optical and structural properties of thermally co-deposited Au-C60 nanocomposite thin films on a quartz substrate is investigated by irradiating samples at different doses. To determine the exact gold (Au) concentration in the film and thickness of the film, Rutherford Backscattering Spectrometry (RBS) was utilized on the as-deposited film. The Surface Plasmon Resonance (SPR) of Au nanoparticles embedded into the fullerene C60 matrix was seen at 721 nm in the as-deposited sample. A ∼34 nm redshift in SPR wavelength was obtained at a dose of 1 × 1014 ions/cm2 which was mainly due to the increase in the size of Au nanoparticles with irradiation. At higher doses, a blue shift of ~67 nm was obtained at a dose of 1 × 1016 ions/cm2 which was due to the transformation of fullerene C60 matrix into amorphous carbon with a much lower dielectric constant at higher doses. The progressive transformation of fullerene C60 into amorphous carbon with increasing doses was confirmed by Raman spectroscopy. The size of Au nanoparticles in the highest dose irradiated sample was found to be ∼3.9 nm by High-Resolution Transmission Electron Microscopy (HRTEM) bright-field measurements. The size modifications of nanoparticles and SPR wavelength tuning of these nanoparticles are very much needed to use them in organic solar cell.

Under swift heavy ion irradiation at different fluences, the structural transformations of fullerene C70 thin film prepared by thermal evaporation are investigated. Fullerene C70 thin films are irradiated with 65 MeV Ni ions beam at different fluences from 1 × 1012 to 1 × 1014 ions/cm2. The impact of energetic ions on the fullerene molecule leads to the extinction of C70 molecule. In order to study the stability of fullerene C70 under ion irradiation, damage cross section and ion track radius of damaged cylindrical zones are determined using fullerene C70 vibration modes and their change at different fluences as recorded by Raman spectroscopy. Damage cross section is found to be 1.01 × 10−13 cm2, and ion track radius of damaged cylindrical zone is found to 1.8 nm. Fullerene C70 is completely converted from crystalline structure to amorphous carbon at a fluence of 1 × 1014 ions/cm2.

Gold–fullerene C60 nanocomposite thin films prepared by thermal co-deposition were irradiated by a high energy beam of 120 MeV Ag ions using Pelletron accelerator. Absorption spectra revealed a large and progressive tuning of surface plasmon resonance wavelength when the films were irradiated at higher fluences. This blue shift (~ 119 nm) can be ascribed to the evolution of fullerene into amorphous carbon upon bombardment of high energy ions at higher fluences and causes a shift in refractive index of the matrix. Raman spectra ascertained this transformation with the presence of two bands: D and G band. Ion irradiation also leads to the formation of bigger size Au nanoparticles with well defined spherical shape at higher fluences as confirmed by TEM. XRD results demonstrated decrease in FWHM of diffraction peaks indicating the increase in particle size which is in agreement with the result obtained from TEM analysis.

In this study, we analyzed changes in the phases of aluminum tris 8–hydroxyquinoline (Alq3) after thermal treatment at different temperatures and their photo–physical properties. We prepared α–Alq3 phosphor via the co–precipitation method. Improvements in the phase purity due to stagnation of the α–phase and the transformation from α to e–Alq3 were achieved by thermal treatment in an Ar atmosphere. The initial formation, stagnation, improvement in the phase purity, and conversion to e–Alq3 were confirmed by X–ray diffraction (XRD) analysis. The XRD results were also validated by Fourier–transform infrared spectroscopy and Nuclear magnetic resonance spectroscopy. Ultraviolet–visible (UV–Vis) absorption spectroscopy was conducted in the presence of acidic and basic media at concentrations of 10−6 M to 10−3 M, respectively. The modifications in the UV–Vis absorption spectra indicated changes in the band gap energy (Eg) after thermal treatment. The variations in Eg for α and e–Alq3 supported the stagnation and transformation of the phase. Photoluminescence (PL) analysis of the as–prepared α–Alq3 determined a λemi maximum at 516 nm. A minor blue shift of Δλ = 2 nm was observed as the PL intensity increased for the annealed α–Alq3. A large blue shift of Δλ = 18 nm as the PL intensity decreased was due to the change in phase from α to e–Alq3. PL study of the α and e–Alq3 phases in acidic solvent detected blue shifts, whereas red shifts occurred in the basic solvents due to variations in their dielectric constants. The mechanism related to the solvatochromatic effect on the shifts in PL emission was also determined in this study. Thermogravimetric analysis was employed to determine the thermal stability of the prepared phosphors.

A low bandgap D–D–A (D = donor; A = acceptor) type conjugated molecular triad TPA-SN5-DCV has been implemented in solution-processed organic solar cells using PC71BM as acceptor. The molecule showed a narrow optical energy gap of 1.59 eV, and a broad absorption spectrum ranging from 350 to 750 nm. Cyclic voltammetry measurements were used to estimate the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels and are −5.10 and −3.53 eV, respectively. After the optimization of the donor and acceptor (PC71BM) weight ratio, the device based on as cast TPA-SN5-DCV:PC71BM (1:2) active layer exhibited overall PCE of 3.34%, which was improved to 6.31% using 0.3 vol % 1,8-diiodooctane (DIO) as solvent additive (SA). Further optimization of the DIO-treated active layer via thermal annealing (TA) resulted in a markedly improved PCE of 7.26%. The enhancement in PCE after either SA or SA + TA treatment is largely accredited to the increase in both JSC and FF, which is associated with ...

The spin-coated thin films of Poly(3-Hexylthiophene) (P3HT) on the glass and Si (double side polished) substrates have been irradiated with 55 MeV Si+4 swift heavy ions (SHI) at fluences in the range from 1 × 1010 to 1 × 1012 ions/cm2. Structural modifications produced by energetic ions are observed by characterization of pristine and irradiated P3HT thin films. Different techniques like high-resolution X-ray diffraction (HR-XRD), micro-Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to analyze the structural changes in the material. A significant increase in crystallinity and room temperature electrical conductivity of P3HT film has been detected on exposure to the heavy ions. The observed increase in the electrical conductivity with increased fluences is explained in the light of improved ordering of polymer chains after irradiation. Mott's variable range hopping model has been used to explain the conduction mechanism in the material in the temperature range of 230–350 K. The modification in surface properties also observed using AFM analysis and contact angle measurement. It is observed that nature of the P3HT thin films remains hydrophobic after irradiation.

Structural as well as optical modifications in zinc oxide (ZnO) thin film with Ag ion implantation were carried out in the present study. The pure ZnO thin films were synthesized by RF-magnetron sputtering technique at room temperature. 120 keV Ag ion beam was used for Ag ion implantation with different implantation dose from 3 × 1014 to 3 × 1016 ions/cm2 by negative ion implantation facility. The thickness and composition of pure ZnO and Ag implanted film at higher dose 3 × 1016 ions/cm2 were estimated by Rutherford backscattering spectroscopy. The change in surface stoichiometry was estimated by using X-ray photoelectron spectroscopy with Ag ion implantation. The modifications in structural features with Ag ion implantation in ZnO films were observed by X-ray diffraction technique (XRD). The pure ZnO thin film was preferentially grown in c-axis direction with crystallite size ~10.6 nm confirmed by XRD. Surface morphology of the pure and Ag implanted ZnO thin films was estimated by atomic force microscopy and revealed the roughness and grain size were increased with increasing the implantation dose. The transmittance of the films was decreased drastically at higher implantation dose as corroborated by UV–visible spectroscopy. Raman spectroscopy of the films was used to understand the lattice defects and disordering during Ag ion implantation. At the higher dose, the film was entirely oriented in c-axis confirmed by X-ray pattern, which can be beneficial for device fabrication.

The formation of silver (Ag) nanoparticles in a ZnO matrix were successfully synthesized by RF-magnetron sputtering at room temperature. As prepared Ag-ZnO nanocomposite (NCs) thin films were annealed in vacuum at three different temperatures of 300 °C, 400 °C and 500 °C, respectively. The structural modifications for as-deposited and annealed films were estimated by X-ray diffraction and TEM techniques. The crystalline behavior preferably along the c-axis of the hexagonal wurtzite structure was observed in as-deposited Ag-ZnO film and improved significantly with increasing the annealing temperature. The crystallite size of as-deposited film was measured to be 13.6 nm, and increases up to 28.5 nm at higher temperatures. The chemical composition and surface structure of the as-deposited films were estimated by X-ray photoelectron spectroscopy. The presence of Ag nanoparticles with average size of 8.2 ± 0.2 nm, was confirmed by transmission electron microscopy. The strong surface plasmon resonance (SPR) band was observed at the wavelength of ∼565 nm for as-deposited film and a remarkable red shift of ∼22 nm was recorded after the annealing treatment as confirmed by UV-visible spectroscopy. Atomic force microscopy confirmed the grain growth from 60.38 nm to 79.42 nm for as-deposited and higher temperature annealed film respectively, with no significant change in the surface roughness. Thermal induced modifications such as disordering and lattice defects in Ag-ZnO NCs thin films were carried out by Raman spectroscopy. High quality Ag-ZnO NCs thin films with minimum strain and tunable optical properties could be useful in various plasmonic applications.

A series of dysprosium (Dy) doped LiMn2O4 based spinel cathode materials, LiMn2 − xDyxO4 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) for Li ion rechargeable battery application were synthesized by sol-gel process. The physical properties were explored through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray diffraction (EDX), field emission scanning electron microscopy (FE-SEM), and micro-Raman spectroscopy. Swagelok cell configurations were used for electrochemical characterizations e.g. cyclic voltammetry, rate performance, cycleability and AC impedance. The doping amount of dysprosium has improved the surface morphology (particle size

Hf 1-x Zr x O 2 gate dielectric thin films were deposited on Si (100) substrates by RF reactive co-sputtering with the variation in the RF power of zirconium target. The compositional, morphological, structural and optical properties of Hf 1-x Zr x O 2 films with various Zr content are systematically investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction and Raman spectroscopy, respectively. The electrical properties of the co-sputtered thin films were studied by capacitance-voltage and current density-voltage measurements. The Zr content in sputtered Hf 1-x Zr x O 2 film was found to be increased up to 19% at a RF power of 90 W. With the increase in Zr content, the enhancement in the crystalline behaviour of co-sputtered film is observed. FESEM micrographs depicted the increase in the grain size with rise in RF power of Zr target. The major generated phase of Hf 1-x Zr x O 2 film is the zirconium-substituted monoclinic phase as revealed from Raman spectroscopy study. The oxide (Q ox ) and interface charge density (D it ) were estimated from the high frequency (1 MHz) Capacitance–voltage curve. The D it has a minimum value for the film deposited at a RF power of 45 W for Zr target, which is due to the reduction of unsaturated bonds and structural relaxation at the Hf 1-x Zr x O 2 /Si interface.

In the present work, we study the annealing and swift heavy ion (SHI) beam induced modifications in the optical and structural properties of sandwiched structured Carbon-gold-Carbon (a-C/Au/a-C) nanocomposite (NCs) thin films. The NCs thin films were synthesized by electron-beam evaporation technique at room temperature with ∼30 nm thickness for both carbon layer and ∼6 nm for gold layer. Gold-carbon NCs thin films were annealed in the presence of argon at a temperature of 500 °C, 600 °C and 750 °C. The NCs thin films were also irradiated with 90 MeV Ni ions beam with different ion fluences in the range from 3 × 1012, 6 × 1012 and 1 × 1013 ions/cm2. Surface plasmon resonance (SPR) of Au nanoparticles are not observed in the pristine film but, after annealing at temperature of 600 °C and 750 °C, it was clearly seen at ∼534 nm as confirmed by UV–visible absorption spectroscopy. 90 MeV Ni irradiated thin film at the fluence of 1 × 1013 ions/cm2 also show strong absorption band at ∼534 nm. The growth and size of Au nanoparticle for pristine and 90 MeV Ni ion irradiated thin film with fluence of 1 × 1013 ions/cm2, were estimated by Transmission electron microscopy (TEM) images with the bi-model distribution. The size of the gold nanoparticle (NPs) was found to be ∼4.5 nm for the pristine film and ∼5.4 nm for the irradiated film at a fluence of 1 × 1013 ions/cm2. The thickness and metal atomic fraction in carbon matrix were estimated by Rutherford backscattering spectroscopy (RBS). The effect of annealing as well as heavy ion irradiation on D and G band of carbon matrix were studied by Raman spectroscopy.

High energy ion irradiation significantly affects the size and shape of nanoparticles in composites. Low concentration metal fraction embedded in fullerene matrix in form of nanocomposites was synthesized by thermal co-evaporation method. Swift heavy ion irradiation was performed with 120 MeV Au ion beam on Cu-C60 nanocomposites at different fluences 1 × 1012, 3 × 1012, 6 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Absorption spectra demonstrated that absorption intensity of nanocomposite thin film was increased whereas absorption modes of fullerene C60 were diminished with fluence. Rutherford backscattering spectroscopy was also performed to estimate the thickness of the film and atomic metal fraction in matrix and found to be 45 nm and 3%, respectively. Transmission electron microscopy was performed for structural and particle size evaluation of Cu nanoparticles (NPs) in fullerene C60 matrix. A growth of Cu nanoparticles is observed at a fluence of 3 × 1013 ions/cm2 with a bi-modal distribution in fullerene C60. Structural evolution of fullerene C60 matrix with increasing fluence of 120 MeV Au ion beam is studied by Raman spectroscopy which shows the amorphization of matrix (fullerene C60) at lower fluence. The growth of Cu nanoparticles is explained using the phenomena of Ostwald ripening.

Metal-fullerene nanocomposite thin films with low concentration of Cu metal embedded in fullerene matrix have been synthesized using thermal co-deposition method. An ion irradiation with 120 MeV Ag ions beam was performed to assess the radiation effects for Cu (3%)-C60 nanocomposites at different fluences 1 × 1012, 6 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Optical properties and surface morphology of nanocomposite thin films were studied using UV-visible spectroscopy and atomic force microscopy, respectively. Absorption spectra demonstrated that absorption intensity of nanocomposite thin film was increased and modes of fullerene were diminished with fluence. The thickness of the film and atomic metal fraction in matrix were estimated by Rutherford backscattering spectroscopy and found to be ∼45 nm and 3%, respectively. Transmission electron microscopy was performed for structural and particle size evaluation of Cu nanoparticles (NPs) in matrix at higher fluence. Structural evolution of copper-fullerene C60 nanocomposite thin films with increasing fluence of 120 MeV Ag ion beam was studied by Raman Spectroscopy, which confirmed the amorphization of matrix (fullerene C60) at higher fluence.

Hf1−xTixO2 dielectric thin films were deposited on Si (100) substrates by RF reactive co-sputtering with the variation in RF power of Ti target. The compositional, morphological, structural and optical properties of Hf1−xTixO2 films with various Ti concentration were systematically investigated by X-ray photoelectron spectroscopy (XPS), Field emmission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman spectroscopy techniques respectively. The electrical properties of the co-sputtered thin films were studied by capacitance–voltage and current density–voltage measurements. The XRD study has shown the enhancement in the the crystalline property of Hf1−xTixO2 film up to 60 W of Ti target power and amorphous like behaviour was observed for higher RF power. The Ti content in Hf1−xTixO2 was calculated from the XPS measurements, where the Ti content was found to be increased with rise in RF power. FESEM micrographs depict the increase in grain size upto the RF power 60 W. The Raman spectrum of the Hf1−xTixO2 film has shown that the major generated phase was titanium-substituted monoclinic phase of HfO2. The flatband voltage (Vfb) and oxide charge density (Qox) were extracted from the high frequency (1 MHz) C–V curve. The Dit has a minimum value for the film deposited at 60 W RF power of Ti target. The leakage current density of the Hf1−xTixO2 films was found to be minimum for the RF power 60 W.

Fullerene C60 thin films with a thickness of ∼120 nm were synthesized by thermal evaporation method on glass substrate. The deposited thin films are irradiated with 90 MeV Ni ions in the fluence range from 1 × 109 to 3 × 1013 ions/cm2. The pristine and irradiated fullerene C60 thin films are examined to study the effect of energy deposition by 90 MeV Ni ions on the optical and structural properties by UV–visible absorbance spectroscopy and Raman spectroscopy, respectively. UV–visible absorbance spectroscopy study reveals that the absorbance peaks decline with the fluence and at particular fluence (∼3 × 1013 ions/cm2) all the absorbance peaks disappear. Apart from this, a decrease in band gap has also been observed with increasing fluence. Raman study confirms that the effect of 90 MeV Ni ion irradiation is observed in two phases. In the lower fluence region, polymerization of C60 molecules is observed and in higher fluence region, destruction of the molecules comes into picture. At fluence 3 × 1013 ions/cm2, fullerene C60 thin film transformed into amorphous carbon (a-C). The transformation of fullerene into a-C is also confirmed through conductivity measurement.

The modifications produced by 55 MeV Si 4+ swift heavy ion irradiation on the phenyl C 61 butyric acid methyl ester (PCBM) thin films (thickness ∼ 100 nm) has been enlightened. The PCBM thin films were irradiated at 1 × 10 10 , 1 × 10 11 and 1 × 10 12 ions/cm 2 fluences. After ion irradiation, the decreased optical band gap and FTIR band intensities were observed. The Raman spectroscopy reveals the damage produced by energetic ions. The morphological variation were investigated by atomic force microscopy and contact angle measurements and observed to be influenced by incident ion fluences. After 10 11 ions/cm 2 fluence, the overlapping of ion tracks starts and produced overlapping effects.

Cu-C60 nanocomposite thin films are synthesized by co-deposition restive heating method on glass, silicon, and TEM grid substrates. Rutherford backscattering spectroscopy (RBS) analysis is used for determining the composition of Cu and thickness of thin film which one found to be ∼13 at% and ∼28 nm, respectively. The deposited thin films are irradiated with 100 keV Ag ion at different fluences ranging from 1 × 1014 to 3 × 1016 ions/cm2. Being of low energy, Ag ions got implanted in SiO2 substrate up to a depth of 30–40 nm that results in wide surface plasmon resonance (SPR) band in combination with SPR of Cu nanoparticles. UV-visible absorption spectroscopy demonstrates the SPR peak arises due to copper nanoparticles embedded in fullerene C60 matrix on irradiation of nanocomposite thin film and its variation under implantation of Ag nanoparticles in SiO2 substrate. Structural modifications due to ion irradiation are analyzed by Raman and transmission electron microscopy (TEM). Raman spectroscopy study reveals the transformation of fullerene C60 into amorphous carbon (a-C) with increasing fluence. Variation in particle distribution is observed under TEM. The average particle sizes are found to be ∼4 ± 0.7 and ∼6 ± 0.4 nm for pristine and 100 keV Ag ion-irradiated thin films, respectively. Atomic force microscopy (AFM) confirms the increase in grain size with increase in roughness of nanocomposite thin films under the effect of implantation. X-ray photoelectron spectroscopy (XPS) confirms the presence of Cu and C from their chemical bonding in Cu-C60 nanocomposite thin films.

In the present work, swift heavy ion (SHI) irradiation induced modifications in structural and optical properties of Ag-ZnO nanocomposite thin films have been investigated. Ag-ZnO nanocomposite (NCs) thin films were synthesized by RF magnetron sputtering technique and irradiated with 100 MeV Ag7+ ions at three different fluences 3 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Rutherford Backscattering Spectrometry revealed Ag concentration to be ∼8.0 at.%, and measured thickness of the films was ∼55 nm. Structural properties of pristine and irradiated films have been analyzed by X-ray diffraction analysis and found that variation in crystallite size of the film with ion irradiation. X-ray photoelectron spectroscopy (XPS) indicates the formation of Ag-ZnO nanocomposite thin film with presence of Ag, Zn and O elements. Oxidation state of Ag and Zn also estimated by XPS analysis. Surface plasmon resonance (SPR) of Ag nanoparticle has appeared at ∼475 nm in the pristine thin film, which is blue shifted by ∼30 nm in film irradiated at fluence of 3 × 1012 ions/cm2 and completely disappeared in film irradiated at higher fluences, 1 × 1013 and 3 × 1013 ions/cm2. A marginal change in the optical band gap of Ag-ZnO nanocomposite thin film is also found with increasing ion fluence. Surface morphology of pristine and irradiated films have been studied using Atomic Force Microscopy (AFM). Raman and Photo-luminance (PL) spectra of nanocomposite thin films have been investigated to understand the ion induced modifications such as lattice defects and disordering in the nanocomposite thin film.

In current research work, we are presenting dysprosium (Dy) doped spinel cathode materials LiMn 2-x Dy x O 4 (x=0.0, 0.01, 0.02, 0.03) and it’s applications as cathode materials in lithium ion rechargeable batteries (LIRB) using a simple and sober sol-gel process. New materials were characterized using x-ray diffractometer and scanning electron microscope (SEM) which informed about the spinel phase purity and small grain size (∼1µm) compared to pristine LiMn 2 O 4 . The elementary electrochemical characterizations revealed that reversible and fast diffusion of Li + ions have improved reversibility and initial specific capacity 124.18 and 124.68 mAhg -1 for Dy01 and Dy02 respectively which 103% of 120 mAhg -1 specific capacity LiMn 2 O 4 at C/10 rate. The AC impedance spectra showed that the reduction in overall impedance via Dy doping in LiMn 2 O 4 . The galvenostatic charge-discharge study revealed the improved rate performance of doped LMO-Dy02 cathode.

Nanoparticles of gold in carbon are synthesized by co-sputtering of gold and graphite in high vacuum chamber using neutral Ar atom beam. Thin films are deposited on glass, Si and carbon coated Cu TEM grid substrates. These films are irradiated with 120 MeV Ag ions at different fluences 1x1012, 5 x1012, 1 x 1013 and 3 x 1013 ions/cm2 using Pelletron accelerator. The structural and optical properties of pristine and irradiated nanocomposite thin films are characterized by transmission electron microscopy and UV-visible absorption spectroscopy, respectively. The Au nanoparticles are observed to be too small (~ 1.5 nm) to excite the plasmon resonance in the pristine film. With ion irradiation, a clear but broad SPR peak is found at ~ 526 nm for the nanocomposite thin film irradiated at a fluence of 1 x 1013 ions/cm2, which is slightly red shifted to ~ 529 nm at a fluence of 3 x 1013 ions/cm2 with a broader width. The red shift is ascribed to the growth of the particles due to enhanced diffusion and ostwald ripening. The average particle size at 3 x 1013 ions/cm2 fluence is found to be ~ 2.1 nm. The sharp rings in selected area electron diffraction pattern also confirmed the growth of the Au nanoparticles.

We have synthesized LiMn2–xFexO4 (x = 0, 0.25, and 0.50) cathode materials for applications in Li ion rechargeable batteries via sol-gel method. We studied thermal characteristics of as synthesized materials using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In order to optimize the synthesis conditions, we studied X-ray diffraction (XRD) of synthesized cathode materials at various temperatures, based on the transitions obtained from DSC/TGA. The XRD results can be co-related to the thermal behavior of the synthesized cathode materials and the synthesis conditions optimized.

This study presents the comparative modifications in optical, structural and morphological properties of fullerene C70 thin film induced by swift heavy ion irradiation and thermal annealing. Fullerene C70 thin films are prepared by resistive heating method on quartz substrates. One set of the films are irradiated with 125 MeV Au ions at different fluences varying from 1×1012 to 3×1013 ions/cm2 and second set of the films are annealed at temperatures varying from 50 to 350 C for 30 minutes. The UV-visible spectroscopy and Raman spectroscopy are performed on pristine, irradiated and annealed films to investigate the modification in optical and structural properties after irradiation and annealing. UV-visible spectra show that the optical band gap of fullerene C70 film decrease with increasing fluence and temperature. The experiment using Raman scattering exhibits the transformation of fullerene C70 into amorphous carbon at higher fluences and higher temperatures as well. This transformation is evidenced by the presence of D and G bands of amorphous carbon in irradiated and annealed films. Atomic force microscopy is performed to observe the variation in surface roughness of films variation with irradiation and temperature. Swift ion irradiation induces the cylindrical zone so called “ion track” made of amorphous materials with in the fullerene C70 thin films. The damage cross-section and radius of cylindrical zone is calculated to be 2.8 ×10-13 cm2 and 3.0 nm respectively using the kinetics of damage of fullerene C70.

The modifications of Poly(3-Hexylthiophene) (P3HT) thin films have been investigated by irradiating with 90 MeV Ni7+ ions at different fluences (1 × 109 to 1 × 1011 ions/cm2). Thin films have been characterized by micro-Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), UV-visible absorption Spectroscopy, Photoluminescence spectroscopy (PL), Atomic Force Microscopy (AFM) and small angle X-ray scattering (SAXS) analysis. The narrow FWHM of C=C mode and the larger intensity ratio of C-C and C=C modes are identified at low fluences. The IR active modes with increased intensity indicates the increased conjugation length, while the XRD analysis revels the improved crystallinity with enhanced molecular ordering. The XPS analysis shows that chemical bonding nature near the film surface is not affected by irradiation. The room temperature electrical conductivity is found to be increased from 2.48 × 10−6 to 1.35 × 10−5 Ω−1cm−1 at the fluence of 1 × 1010 ions/cm2. The temperature dependence of dc conductivity has been explained using Mott's variable range hopping model. SAXS detector images confirm the presence of ion tracks and density variation between the track core and halo regions. It is found that less intense heating effect in the halo region of ion path could induce the molecular ordering of P3HT.

In this study, nanoparticles of pure zinc oxide (ZnO) and ZnO doped with iron of various doping concentrations (Zn1- xFexO) are analyzed using fluorescence spectroscopy. Excitation and emission spectra using various operating wavelengths were collected. Individual spectra and excitation emission matrix were analyzed. Various peaks including strong ultraviolet (UV) emission peaks and strong blue emission peaks that are corresponding to the near-band-edge emission (NBE) and defect emission (DE) peaks were studied based on the peak intensities, peak wavelengths, and NBE peak to defect peak ratios. The Zn1-xFexO materials were also analyzed using X-ray diffraction and optical absorption spectroscopy. The variation in the band gap energy and in the NBE emission energy with dopant concentration was analyzed. A red-shift was observed with the NBE emission peak. The NBE to DE ratio initially increases from pure ZnO to Zn0.97Fe0.03O and then decreases as the dopant concentration increases.

Herein, we report blue-emitting methoxy-substituted 2, 4-diphenyl quinoline phosphor prepared using acid-catalyzed Friedlander reaction along with the enhancement in the phase purity due to employed thermal treatment in Ar atmosphere. Improvement in the phase purity of the phosphor leading to a change in their optical properties is reported. XRD and FTIR analyses confirm the formation and improvement in the phase purity of the phosphor. TG/DTA analysis endorses the change in their behavior and thermal stability. The modification in optical band gap of the phosphors due to thermal treatment has been confirmed from the UV–vis spectroscopy. Enhancement in the fluorescence intensity of blue-emitting phosphor due to thermal treatment has been described through photoluminescence analysis. Luminescence decay profile has also been recorded using time-correlated single-photon counting (TCSPC) system for the lifetime analysis of the phosphors which supports the obtained PL analysis. The overall study indicates that methoxy-substituted 2, 4-diphenyl quinoline phosphor which was annealed at 90 °C in Ar atmosphere serves better fluorescence intensity, thermal stability and lifetime profile, and may be utilized for the organic display applications.

Au-Fullerene nanocomposite thin films synthesized by thermal co-evaporation method are irradiated by low energy (2.6 MeV) Ar ions at fluence ranging from 1 × 1014 ions-cm−2 to 3 × 1016 ions-cm−2. To avoid the retrogression of attributes of fullerene subjected to presence of Au, selected concentration and thickness of gold film is kept very small. UV–visible spectroscopy demonstrates the surface plasmon resonance (SPR) peak at 677 nm for the pristine film and at 590 nm after irradiation at fluence of 1 × 1014 ions-cm−2, displaying a shift of 87 nm towards lower side. This confirms that the refractive index of fullerene decreases as an influence of exposure to Ar beam irradiation. Shift in refractive index is explained on the basis of Mie theory which is established by the existence of D and G band after irradiation as displayed in the results of Raman Spectroscopy. A slight increase in the size of Au nanoparticles in irradiated films is observed which is illustrated by TEM images. Atomic Force Microscopy (AFM) images indicate the varying roughness of thin films after irradiation and morphology is determined by SEM images. I-V characterization shows the conductive behavior of Au-fullerene nanocomposite film before and after irradiation at different fluence. There are two phenomena occurring simultaneously with the increase in ion irradiation fluence; one is increase in the size of metal nanoparticle and another is transformation of fullerene in amorphous carbon. This leads to the change in the SPR position of metal fullerene nanocomposite thin film, making ion irradiation as an effective tool to enhance and optimize the optical properties of metal fullerene nanocomposite thin film.

There is an increasing demand for fast and sensitive determination of antidepressants in human body fluids because of the present scenario of rising depression cases at the global level. A simple and sensitive voltammetric method using edge plane pyrolytic graphite electrode (EPPGE) as a novel sensor is presented for the determination of antidepressant fluvoxamine in urine and blood plasma samples of obsessive-compulsive disorder (OCD) patients. EPPGE is delineated the first time for this determination. EPPGE exhibited strong electrocatalytic activity and enhanced reduction signal towards the sensing of fluvoxamine. Fluvoxamine gave a well-defined reduction peak at ~ – 670 mV using EPPGE. The fluvoxamine reduction peak current was linear to its concentration in the range 5.00 × 10−9 – 0.1 × 10−6 mol L−1 and the limit of detection was found to be 3.5 × 10−9 mol L−1. The pre-eminence of EPPGE over mercury electrodes has been proved in terms of sensitivity and imperative analytical parameters. The pH study reveals the involvement of an equal number of electrons and protons in the reduction reaction mechanism. The frequency study indicated the adsorption controlled irreversible reaction mechanism. The stability and reproducibility of the offered sensor were also found most favorable. The interference study confirmed the optimum selectivity of the proposed sensor. The edge plane pyrolytic graphite sensing platform is recommended as a potential contender for the accurate and fast determination of fluvoxamine in depression medications as well as biological specimens of OCD patients.

Fullerene C 70 thin films were deposited by resistive heating on glass substrates and the thickness were approximated to be 150 nm. The effect of energy deposition by 55 MeV Si ions on the optical and structural properties of the prepared thin film samples is investigated. The samples were irradiated with 55 MeV Si ions within fluence range from 1 × 10 12 to 3 × 10 13 ions/cm 2 . For optical studies, the pristine and the Si ion irradiated samples are examined by UV–visible absorption spectroscopy and Raman spectroscopy. UV–visible absorption studies reveal that the absorption peaks of irradiated samples decrease with a decrease in the band gap of the thin films. The damage cross-section ( σ ) and radius of damaged cylindrical zone ( r ) are determined as ∼0.6 × 10 −13 cm 2 and ∼1.41 nm, respectively from the Raman spectra. Raman studies also suggest that at higher fluence (up to 3 × 10 13 ions/cm 2 ), the damage caused by the SHI results in partial amorphization of fullerene C 70 thin film. Modification in the surface properties has been investigated by atomic force microscopy; it has revealed that the roughness decreases and average particle size increases with the increase in fluences.

Phenyl C61 butyric acid methyl ester (PCBM) is a fullerene derivative and most commonly used in organic photovoltaic devices both as electron acceptor and transporting material due to high electron mobility. PCBM is easy to spin caste on some substrate as it is soluble in chlorobenzene. In this study, the spin coated thin films of PCBM (on two different substrate, glass and double sided silicon) were irradiated using 90 MeV Ni7+ swift heavy ion beam at low fluences ranging from 1 × 109 to 1 × 1011 ions/cm2 to study the effect of ion beam irradiation. The pristine and irradiated PCBM thin films were characterized by UV–visible absorption spectroscopy and fourier transform infrared spectroscopy (FTIR) to investigate the optical properties before and after irradiation. These thin films were further analyzed using atomic force microscopy (AFM) to investigate the morphological modifications which are induced by energetic ions. The variation in optical band gap after irradiation was measured using Tauc’s relation from UV–visible absorption spectra. A considerable change was observed with increasing fluence in optical band gap of irradiated thin films of PCBM with respect to the pristine film. The decrease in FTIR band intensity of C60 cage reveals the polymerization reaction due to high energy ion impact. The roughness is also found to be dependent on incident fluences. This study throws light for the application of PCBM in organic solar cells in form of ion irradiation induced nanowires of PCBM for efficient charge carrier transportation in active layer.

The effect of energy deposition in fullerene C70 (∼150 nm) thin film deposited by resistive heating method on glass, quartz and silicon substrates was investigated. The samples were irradiated with 90 MeV Ni ion beam at the fluences ranging from 1 × 1012 to 3 × 1013 ions/cm2. The pristine and Ni ion irradiated samples were examined for morphological and optical changes by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), UV–visible absorption spectroscopy and Raman spectroscopy. After ion irradiation, bigger grains are shown on surface as revealed by SEM analysis indicating the agglomeration of the smaller particles into bigger particles at the surface. UV–visible absorption studies reflect that the direct band gap of the film decreases with increase in ion fluence. At higher fluence, fullerene C70 is transformed into amorphous carbon (a-C) which is confirmed by Raman spectroscopy. The damage cross-section (σ) and radius of the damaged cylindrical zone (r) are approximated to be ∼1.72 × 10−13 cm2 and ∼2.3 nm, respectively using Raman active vibrational modes.

Different rare-earth elements (Dy, Gd, Tb and Yb) doped LiMn 2 O 4 spinel active material were prepared by sol-gel method. The rare earth doping elements decrease particle size but do not affect the formation of cubic spinel structure. Further, these dopants have strong influence in the overall electrical properties of the cathodes prepared from them. In the cyclic voltammetry measurements, two pairs of separated redox peaks are observed, independently to dopants. LiMn 2 O 4 doped gadolinium (Gd) and dysprosium (Dy) exhibit a comparable room temperature rate capability to pristine LiMn 2 O 4 with discharge capacity of 94.5 mAh g -1 and 82.3 mAh g -1 , respectively, versus 73.4 mAh g -1 for pristine LiMn 2 O 4 at a rate of C5. Terbium (Tb) and ytterbium (Yb) doping show, on the other hand, lower performance. After 50 cycles at C2, the capacity fade is 7% for LiMn 1.95 Dy 0.05 O 4 and 14% for LiMn 1.95 Gd 0.05 O 4 , whereas for LiMn 2 O 4 it is 32%. The improved cycling performance of LiMn 2 O 4 doped with Gd and Dy is attributed to the powder size and atomic radius of the elements. Differences of the capacity retention on cycling are attributed to superior structural stability due to rare earth doping. These results indicate that improved cathode materials doped with rare earth element are suitable for lithium-ion battery applications, This work is funded by FCT – Fundação para a Ciência e a Tecnologia, in the framework of the PTDC/CTM-ENE/5387/2014 and PTDC/EEI-SII/5582/2014 projects. A. G. and C.M.C. also thanks the FCT for the grant SFRH/BD/90313/2012 and SFRH/BPD/112547/2015, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology (INT/Portugal/P-02/2013) 2014-2016. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program. SLM thanks the Diputación de Bizkaia for financial support under the Bizkaia Talent program; European Union’s Seventh Framework Programme; Marie Curie Actions – People; Grant agreement nº 267230.

The Al-induced crystallization of amorphous (a)-Si under thermal annealing and swift heavy ion irradiation has been investigated. The c-Al (50 nm)/a-Si (150 nm) thin films have been prepared on thermally oxidized Si-substrates. A set of samples have been annealed at temperatures ranging from 100 °C to 500 °C to achieve crystallization. Another set of similar samples have been irradiated at an elevated temperature of 100 °C using 100 MeV Ni+7 ions at fluences of 1 × 1012 ions-cm−2, 5 × 1012 ions-cm−2, 1 × 1013 ions-cm−2, and 5 × 1013 ions-cm−2. The crystallization of a-Si is observed at annealing temperature of 200 °C. The crystallinity increases with increasing temperature. On the other hand, irradiation using swift heavy ion leads to crystallization of a-Si at significantly lower temperature of 100 °C. The irradiation induced crystallization is explained in terms of creation of vacancies, interstitials and mixing of Si and Al atoms at a-Si/c-metal interface due to energy deposited by swift Ni ions.

LiMn2-xGdxO4 (x=0.00, 0.01 and x=0.04) spinel active material were prepared by sol-gel method. The morphology, crystal structure, thermal stability and electrochemical properties of the synthesized samples were evaluated. Gd-doping maintains the cubic spinel structure of LiMn2O4, leads to a decrease of the average particle size, and has a strong influence on the electrochemical properties of the cathodes. LiMn2-xGdxO4 cathode materials show two pairs of separated redox peaks, independently of the Gd-doping. After 40 charge-discharge cycles at C2, the discharge capacity was 55.9 mAh.g-1 and 33 mAh.g-1 for x=0.04 and x=0, respectively, corresponding to a capacity retention of 80% and 70%, respectively. The Gd-doped with x=0.04 showed improved cycling performance with respect to pristine LiMn2O4 due the smaller particle size and superior structural stability, showing its suitability for lithium-ion battery applications., The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013. A. G., C.M.C. and S. F. thank the FCT for grants SFRH/BD/90313/2012, SFRH/BPD/112547/2015 and IF/01516/2013, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology grant INT/Portugal/P-02/2013, 2014-2016. The authors are thankful for HRTEM and Raman characterization support from MRC, MNIT, Jairpur, INDIA. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. SLM thanks financial support from the Basque Government Industry Department under the ELKARTEK Program.

Fullerene C70 thins films of thickness ∼150 nm are prepared on quartz and glass substrates with thermal deposition technique. The films are irradiated with different ions (Au, Ag, Ni, Si) having different energies in order to vary the electronic energy loss (Se). The samples are also irradiated with range of fluence i.e. 1×1012 ions/cm2 to 3×1013 ions/cm2 for each energetic ion beam. The damage cross sections due to ion beam irradiation with different energetic ions (120 MeV Ag, 120 MeV Au, 90 MeV Ni, 55 MeV Si and 55 MeV Ni) are determined with Raman spectroscopy. A curve is plotted between electronic energy loss (Se) and damage cross section (σ) that is helpful to determine the damage cross section in fullerene C70 for any electronic energy loss. In addition, radius (r) of ion track can be approximated for any Se value from the constructed curve between r and Se.

The structural and optical properties of bulk heterojunction (BHJ) organic solar cell devices have been studied before and after heat treatment. The BHJ structure is fabricated by making the blend of Poly [3-hexylthiophene] (P3HT) and Phenyl C61 butyric acid methyl ester (PCBM) for active layer. After the heat treatment at 140 °C temperature, the device is characterized by X-ray diffraction (XRD) measurement, Raman spectroscopy and UV-visible absorption spectroscopy. The reduced intensity of XRD peak corresponding to (100) plane and decreased crystallite size was observed after annealing. The Raman peak intensity corresponding to C=C stretching mode and optical absorption peak intensity is also found to be reduced after the heat treatment to the device. The diminished intensitiesafter annealing may be due to diffusion of Al into active layer.