Synthesis and Characterisation of Indium Tin Oxide Thin Films for Dye-Sensitised Solar Cells using Natural Fruit Extracts

The study focuses on the application of natural fruit extract of blackberry in dye-sensitised solar cells (DSSC) as a photosensitiser. The widespread availability of the fruits and juices, high concentration of anthocyanins in them ease of extraction of anthocyanin dyes from these commonly available fruits, enable them as a novel and inexpensive candidates for solar cell fabrication. Anthocyanins are naturally occurring biodegradable and non-toxic compounds that can be extracted with minimal environmental impact and provide environmentally benign alternatives for manufacturing dyes in DSSC synthesis. Indium tin oxide (ITO) thin films are synthesised using sol-gel and spin-coating techniques. ITO characteristics are determined by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transforms infrared spectra (FTIR) measurements. To find the transmittance percentage in the visible region of thin films, atomic force microscope (AFM) and UV-Vis spectroscopy analyses were done. The nanocrystalline phase of the synthesised ITO films was confirmed through XRD. SEM was used to analyse the morphology of the synthesised ITO films. Cubic, columnar (edge length ~ 35-45 nm) and rod-shaped (~110 x 14) particles were observed. Narrow size distribution was observed for spherical particles in the range of ~13-15 nm. The FTIR analysis revealed the presence of carboxyl and hydroxide functional groups. The AFM analysis revealed the uniform spread of the synthesised dye, while the visible region absorbance and transmittance of the synthesised ITO films were confirmed through UV-vis spectroscopy. The thin films showed 83-86% of average transmittance. Finally, we fabricated a dye-sensitised solar cell with desired properties. The characterisation results confirmed that the synthesised material could be used in the DSSC application.

Study on nanocrystalline grain size and quantitative change in Fe–Cu–Mo–Si–B soft magnetic alloy

In this paper, we studied the grain size and volume fraction change of [Formula: see text]-Fe(Si) nanocrystalline phase as a function of Cu, Mo and Si content in Fe[Formula: see text]Cu[Formula: see text]Mo3Si[Formula: see text]B9, Fe[Formula: see text]Cu1Mo[Formula: see text]Si[Formula: see text]B9, Fe[Formula: see text]Cu1Mo3Si[Formula: see text]B[Formula: see text], and also the annealing temperature and time in Fe[Formula: see text]Cu1Mo3Si[Formula: see text]B9 alloy. Cu is an element promoting ultrafine structure and crystallization progresses, it causes the grain size of the [Formula: see text]-Fe(Si) phase to decrease suddenly, the volume fraction of [Formula: see text]-Fe(Si) phase to increase only by adding 0.5 at.% Cu. Also, Mo causes the grain size of [Formula: see text]-Fe(Si) phase to decrease like Cu, while suppressing the increase of the volume fraction of [Formula: see text]-Fe(Si) phase, Si has no little effect on the grain size of [Formula: see text]-Fe(Si) phase, diffuses into the inner part of [Formula: see text]-Fe(Si) phase upto Si 13.5 at.%, but suddenly increases grain size above Si 13.5 at.%. The microstructure of Fe[Formula: see text]Cu1Mo3Si[Formula: see text]B9 alloy is nearly completed at 520[Formula: see text]C for about 20 min, the grain size is approximately 13.8–14.1 nm, the volume fraction of [Formula: see text]-Fe(Si) phase is within 61–66%, initial permeability at 1 kHz is within 59,800–61,100.

Study on Properties and Heat Treatment Process of Fe75.9Cu1Si13B8Nb1.5Mo0.5Dy0.1

The soft magnetic properties of Fe[Formula: see text]Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] nanocrystalline alloy were studied which is designed on the basis of the Finemet type alloys. The X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), electric inductance measuring-testing instrument and MATS soft magnetic material AC/DC tester were used to study the effects of the effective permeability ([Formula: see text], saturation magnetic induction ([Formula: see text]), coercivity ([Formula: see text]), and hysteresis losses ([Formula: see text]) at 100[Formula: see text]kHz and 0.2[Formula: see text]T under factors such as different annealing temperatures, different thicknesses, and whether there is a need for transverse field for annealing. The results show that the commercial amorphous alloy ribbons Fe[Formula: see text] Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] have complete amorphous structure in as-cast state, and [Formula: see text]-Fe nanocrystalline phase precipitates on the amorphous matrix after vacuum annealing. Fe[Formula: see text] Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] alloy has high [Formula: see text] value and good thermal stability, which can better control the formation of nanocrystalline structure. The transverse magnetic field annealing can greatly increase the [Formula: see text] of the material and reduce the [Formula: see text], which is more significant for the ribbons. The optimum annealing process of Fe[Formula: see text]Cu1Si[Formula: see text]B8Nb[Formula: see text]Mo[Formula: see text]Dy[Formula: see text] alloy is that the transverse magnetic field of 1000[Formula: see text]Gs is applied and the temperature is kept at 833[Formula: see text]k for 30[Formula: see text]min. And the best properties for [Formula: see text] are 1.39[Formula: see text]T, for [Formula: see text] is 4.6[Formula: see text]A/m and [Formula: see text]@1[Formula: see text]kHz, [Formula: see text]@100[Formula: see text]kHz. With the high frequency and miniaturization of electronic components, this material has potential application value.

Thermal Transport Evolution Due to Nanostructural Transformations in Ga-Doped Indium-Tin-Oxide Thin Films

We report on a comprehensive theoretical and experimental investigation of thermal conductivity in indium-tin-oxide (ITO) thin films with various Ga concentrations (0–30 at. %) deposited by spray pyrolysis technique. X-ray diffraction (XRD) and scanning electron microscopy have shown a structural transformation in the range 15–20 at. % Ga from the nanocrystalline to the amorphous phase. Room temperature femtosecond time domain thermoreflectance measurements showed nonlinear decrease of thermal conductivity in the range 2.0–0.5 Wm−1 K−1 depending on Ga doping level. It was found from a comparison between density functional theory calculations and XRD data that Ga atoms substitute In atoms in the ITO nanocrystals retaining Ia-3 space group symmetry. The calculated phonon dispersion relations revealed that Ga doping leads to the appearance of hybridized metal atom vibrations with avoided-crossing behavior. These hybridized vibrations possess shortened mean free paths and are the main reason behind the thermal conductivity drop in nanocrystalline phase. An evolution from propagative to diffusive phonon thermal transport in ITO:Ga with 15–20 at. % of Ga was established. The suppressed thermal conductivity of ITO:Ga thin films deposited by spray pyrolysis may be crucial for their thermoelectric applications.

Synthesis and characterization of Co–B–Fe–Ti nanosized alloyed powders

In this study, novel Co60Fe18Ti18B4 alloy powders have been synthesized with high compositional homogeneity using a high-energy ball milling technique. The structural, morphological and mechanical properties of the nanosized alloyed powders were examined using different analytical techniques, including scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry and X-ray diffraction. According to the X-ray diffraction analysis for both Co powder and Co60Fe18Ti18B4 alloy powders, with increasing milling time, the content of Co-based (hcp) solid solution decreased and Co-based (fcc) solid solution increased. The mechanical properties of the material were also investigated by Vickers micro-hardness testing. The micro-hardness value of the Co60Fe18Ti18B4 alloy was found as 120.08 HV. After sintering (1 h– 1000 °C), the hardness improved remarkably (536.32 HV). Furthermore, results indicate that the synthesized Co-based alloy powder has both glassy and nanocrystalline phase forms.

Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon

One-dimensional periodic surface structures were formed by femtosecond laser irradiation of amorphous hydrogenated silicon (a-Si:H) films. The a-Si:H laser processing conditions influence on the periodic relief formation as well as correlation of irradiated surfaces structural properties with their electrophysical properties were investigated. The surface structures with the period of 0.88 and 1.12 μm were fabricated at the laser wavelength of 1.25 μm and laser pulse number of 30 and 750, respectively. The orientation of the surface structure is defined by the laser polarization and depends on the concentration of nonequilibrium carriers excited by the femtosecond laser pulses in the near-surface region of the film, which affects a mode of the excited surface electromagnetic wave which is responsible for the periodic relief formation. Femtosecond laser irradiation increases the a-Si:H films conductivity by 3 to 4 orders of magnitude, up to 1.2 × 10−5 S∙cm, due to formation of Si nanocrystalline phase with the volume fraction from 17 to 28%. Dark conductivity and photoconductivity anisotropy, observed in the irradiated a-Si:H films is explained by a depolarizing effect inside periodic microscale relief, nonuniform crystalline Si phase distribution, as well as different carrier mobility and lifetime in plane of the studied samples along and perpendicular to the laser-induced periodic surface structures orientation, that was confirmed by the measured photoconductivity and absorption coefficient spectra.

Processing and Optical Properties of Eu-Doped Chloroborate Glass-Ceramic

An europium doped BaO–B2O3–BaCl2 chloroborate glass-ceramic containing a BaCl2 nanocrystalline phase was produced by melt-quenching followed by glass crystallization during annealing. Structural and morphological investigations using x-ray diffraction and scanning electron microscopy have shown fvBaCl2 nanocrystals of about tens of nm size accompanied by a smaller amount of the BaB2O4 crystalline phase. Photoluminescence spectra have indicated the reduction of Eu3+ to Eu2+ during processing in air or a reducing atmosphere. The spectra analysis showed the presence of Eu3+ ions in the borate glass matrix, while the Eu2+ were incorporated in both the BaCl2 nanocrystals and glass matrix. Thermoluminescence properties were due to the recombination of F(Cl) centers and Eu2+ related hole centers produced by irradiation within the BaCl2 nanocrystals. The color impression of the samples and the photoluminescence quantum efficiency were influenced by the glass processing.

A new olanzapine cocrystal obtained from volatile deep eutectic solvents and determined by 3D electron diffraction

A previously unknown cocrystal of olanzapine and phenol was identified from a volatile deep eutectic solvent as the intermediate species in the crystallization of olanzapine. This new nanocrystalline phase was investigated by electron diffraction, powder X-ray diffraction and differential scanning calorimetry. The structure was determined by simulated annealing using 3D electron diffraction data and confirmed using DFT-D optimizations. Olanzapine and phenol cocrystallize in the triclinic space group P 1, supporting the hypothesis of a dimeric growth unit, where a centrosymmetric dimer is stabilized by multiple weak C—H...π interactions and forms double N—H...N hydrogen bonding with adjacent dimers.

Towards a Correlation between Structural, Magnetic, and Luminescence Properties of CeF3:Tb3+ Nanocrystals

In this study, we report on the structural, magnetic, and optical properties of Tb3+-doped CeF3 nanocrystals prepared via a polyol-assisted route, followed by calcination. X-ray diffraction analysis and electron microscopy investigations have shown the formation of a dominant Ce0.75F3 nanocrystalline phase (of about 99%), with a relatively uniform distribution of nanocrystals about 15 nm in size. Magnetization curves showed typical paramagnetic properties related to the presence of Ce3+ and Tb3+ ions. The magnetic susceptibility showed a weak inflexion at about 150 K, assigned to the cerium ions’ crystal field splitting. Under UV light excitation of the Ce3+ ions, we observed Tb3+ green luminescence with a quantum yield of about 20%.