Hkl Planes Research Articles

Of ZnO Nanoparticle using Sandoricum Koetjape Peel Extract as Bio-stabilizer under Microwave Irradiation

The use of sentul (Sandoricum koetjape) peel extract as a biostabilizer in the synthesis of zinc oxide (ZnO) nanoparticles has been carried out as an environmentally friendly production. This research was conducted by reacting a 0.2 M of Zn precursor (zinc nitrate hexahydrate) solution with Sentul peel extract (10g/l). The samples were varied based on the ratio of the volume of the Zn solution to the Sentul peel extract, i.e., 1:4, 2:3, 1:1, 3:2, and 4:1 where each sample was assigned a ZSk initial code. The ZnO synthesis used a microwave technique with a power of 360 Watt. Morphological, structural, optical absorption, and functional groups were analyzed based on the results of the characterization of SEM, XRD, UV-Vis, and FTIR Spectroscopy. SEM images show the morphology of ZnO particles in the form of semi-hollow spheres and macaron-like shapes. The particle size decreases with the addition of the volume of the Zn solution. The XRD diffraction pattern shows the diffraction peaks that correspond to the hkl plane of the wurtzite hexagonal structure of ZnO. The highest optical absorption of the UV-Vis spectrum occurred in the wavelength range of 300-360 nm. The FTIR spectrum represents the involvement of the O-H functional groups derived from the polyphenolic compound of sentul peel extract.

Characterization of electrodeposited Ni–MoS2 composite coatings under the influence of current density

In this paper, the influence of current density on electrodeposited Ni–MoS2 composite coatings has been studied for the first time. Low carbon steel alloy has been selected as a substrate. The Ni–MoS2 composite coatings are deposited at a temperature of 48 °C with applied current densities of (1, 2, 3 and 4 A/dm2 ). The x-ray diffraction (XRD) analysis of electrodeposited Ni– MoS2 coatings depicts a number of sharp peaks indicating a good crystallinity. Using ASTM database, the peaks at 14°, 32°, 33°, 39°, 49° and 58° correspond to (200), (100), (101), (103), (105) and (110) hkl planes respectively. The morphology was examined by scanning electron microscopy (SEM). Microhardness measurements show that all Ni–MoS2 samples are harder than low carbon steel substrate. EDX analysis of the Ni–MoS2 composite confirmed that the fraction of MoS2 increased with the increase of applied current density. The study of corrosion properties was carried out in a 0.6M NaCl solution. The potentiodynamic polarization curve of electrodeposited Ni–MoS2 confirmed that the corrosion resistance increases with the decrease of applied current density. In addition, Electrochemical tests show that the optimal value of applied current density is 3 A/dm2 in the sense of the least value of Ecorr = -314,1 mV and the best resistance was Rp = 9.52 K.cm2

Crystal growth and physico-chemical characterization of semi-organic [C4H12N2] ZnCl4·H2O single crystal for laser applications

Optical high-quality semi-organic piperazinium tetrachlorozincate monohydrate, [C4H12N2] ZnCl4·H2O (PTCZ), single crystals were grown by conventional solution method. The structure of grown crystal was confirmed by the single-crystal X-ray diffraction (SXRD) analysis. The material phase purities and its various (hkl) planes have been confirmed by the powder X-ray diffraction (PXRD) analysis at room temperature. The different functional groups were confirmed by the Fourier transform infrared (FTIR) spectroscopy. The optical quality of the PTCZ single crystal and band gap energy have been identified by the UV–Vis–NIR spectral analysis and also calculated refractive index of the material. The thermal stability of the PTCZ single crystal was investigated by TG–DTA. The hardness-related properties were analyzed by microhardness tester. The dielectric properties have been measured on the grown single crystal and the electronic polarizability value has been calculated with various theoretical approaches. The etching was carried out on the grown crystal to find the dislocation density. The crystal atomic perfection has been investigated by the high-resolution X-ray diffraction (HRXRD) or Rocking curve (RC) analysis. The Z-scan measurement has been carried out to find third-order optical susceptibility (χ(3)) of the grown single crystal using solid-state laser (640 nm).

Investigation of opto-electronic properties and morphological characterization of magnesium niobate ceramics synthesized by two-stage process

Orthorhombic magnesium niobate is known to exhibit exceptional dielectric and photoluminescence properties. With the intention to evaluate these properties, MgNb2O6 (MN2) was synthesized at 900 °C for 6 h through a two-stage process. The phase examination was done by XRD and Raman spectroscopy. XRD analysis confirmed orthorhombic crystal structure with average crystallite size of 41 nm, approximately. The d-value and (hkl) plane corresponding to highest intensity was examined 2.9486 Å and (311), respectively. Raman spectroscopic analysis clarified various vibration bands of MN2 ceramics. The grain size was assessed close to 87 nm from FESEM analysis considering the grain distribution plot. The microstructure analysis by HRTEM reveal nanoparticles of average size of 41.83 nm. The clear lattice image and prominent spots in SAED confirm crystallinity of prepared ceramics. The PL result of the prepared ceramics at 900 °C indicated blue emission spectrum near 442 nm. The material prepared at 900 °C exhibited band gap of 2.65 eV using diffuse reflectance spectroscopic analysis. The dielectric constant (εr) and tanδ were also investigated where εr was measured 27.8 and 20.8 for material prepared at 800 and 900 °C, respectively. Low tanδ (dielectric loss) was also noted in present investigation.

Synthesis, crystal growth, and physicochemical characterization of 4-aminopyridinium 4-nitrophenolate 4-nitrophenol (4AP4NP) single crystals for NLO applications

The organic nonlinear optical (NLO) single crystal of 4-aminopyridinium 4-nitrophenolate 4-nitrophenol (4AP4NP) single crystal was grown by the solution method at room temperature. The unit cell parameters of the grown 4AP4NP single crystal were confirmed by single-crystal X-ray diffraction (SXRD) measurement. The various (hkl) planes of the grown crystal and their average lattice strain were analyzed by powder X-ray diffraction (PXRD). The crystalline perfection of the 4AP4NP single crystal was analyzed by high-resolution X-ray diffraction (HRXRD) measurement. The optical quality of 4AP4NP single crystal and its cut-off energy were analyzed by UV–Vis–NIR. The photoluminescence (PL) study reveals that the grown crystal has high-intense green emission at 500 nm. The thermal stability of the grown crystal was analyzed by TG/DTA. The mechanical stability was analyzed by Vickers microhardness measurement. The dislocation density of 4AP4NP crystal has been investigated by etching studies. Laser-induced damage threshold (LDT) of the 4AP4NP crystal was analyzed by Q-switched Nd:YAG laser of wavelength 532 nm. The optical homogeneity of 4AP4NP was determined by the birefringence interferometry technique. The dielectric measurement has been carried on the grown crystal. The electronic polarizability (α*) of the grown crystal was determined by various theoretical calculations. The second-harmonic generation (SHG) and third-order nonlinear optical properties of the grown 4AP4NP crystal were analyzed by Kurtz–Perry powder and Z-scan technique, respectively.

Simple and fast method for determination of preferred crystallographic orientation of nanoparticles: A study on ZnS/kaolinite nanocomposite

Crystallographic orientation of nanoparticles anchored on surface of solid crystalline matrix plays an important role in the resulting activity (e.g. the catalytic activity) of such structured nanocomposites. Possibility to predict the crystallographic orientation can thus be advantageous in many areas of materials science. This study presents a simple method of such prediction by determining the structure compatibility of two crystal structures based on the average number of pairs of overlapping atoms calculated from the mutual rotation of two (hkl) planes: one plane belonging to the nanoparticle crystal structure, the second one belonging to the matrix crystal structure. In this work, the structure compatibility of photocatalytic ZnS nanoparticles and tetrahedral kaolinite surface was studied. Results were compared with molecular simulations and with the high-resolution transmission electron microscopy analysis performed on a sample of the real ZnS/kaolinite nanocomposite. All three approaches led to identical result: the same preferred crystallographic orientation of ZnS on the tetrahedral surface of kaolinite was found. The method of determining structure compatibility is the fastest of the three approaches used, and thus appears to be very suitable for the purpose of predicting the preferred crystallographic orientation.

Structural, optical and morphological properties of zinc -doped cobalt-ferrites CoFe2−xZnxO4 (x=0.1-0.5)

Cobalt-ferrite (CoFe2O4) based nanoparticles are appropriate candidates for electrical, optical, and magnetic applications for electrical appliances. In the current study, a coprecipitation technique was used to prepare Zinc doped cobalt ferrites with compositions CoFe2−xZnxO4 (x=0.1-0.5) at various percentages using Zinc and Co-nitrate as precursors. The analysis of crystal phase structure, hkl planes, average crystalline size, volume, and lattice parameters of the unit cell of CoFe2-xZnxO4 doped (NPs) was carried under X-ray diffraction (XRD). X-ray spectra analysis, FT-IR Spectra, UV Visible Spectra, and SEM studies shown that the as-synthesized powders were contained of nano-crystallite size (42– 53nm) cubic-spinel phase with irregularly-structure. Calcination at low temperature (80˚C) of the precursor followed through sintering (500°C for 3h) con-sequence in a single-phase cubic-spinel shape with an average particle size of 42-53nm, as shown by scanning electron micrographs images. Sharp peaks and intense diff raction features in XRD pattern show that an increase in Zn doping concentration in cobalt spinel ferrite increases the crystalline behavior of the cubical spine phase. In cubical structure ferrites crystal lattices, the absorption band at low frequency is noticed above 400cm-1 but in the range of 300- 600cm-1 of the Fourier Transform Infrared bands were attributed to the tremblant of the ions of metal. The absorbance results of UV Spectra indicate that Zinc doped Cobalt Ferrite specimen had symbolic absorbance in the range of 660-900nm wavelength range of the conspicuous region. The Zn-doped cobalt-ferrite have a high strain derivative that could be a prospective material for electrical devices.

Seed-Mediated Synthesis and Photoelectric Properties of Selenium Doped Zinc Oxide Nanorods

Pristine ZnO and selenium doped ZnO (Se-ZnO) nanorods were successfully synthesized using seed-mediated hydrothermal method. The growth solution of both pure and Se-doped ZnO nanorods employed zinc nitrate hexahydrate (ZNH) and hexamethylenetetramine (HMT) as a precursor and surfactant, respectively. As a dopant source, selenium salt solution was obtained by reacting selenium powder with sodium borohydride at low temperature. The as-prepared pure ZnO and Se-doped ZnO nanorods were characterized using field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-Visible spectroscopy (UV-Vis), and Photoluminescence (PL) spectroscopy. FESEM images show that the geometric shape of Se-ZnO nanoparticles is nanorods with a hexagonal cross-section. The XRD pattern shows the diffraction peak of the sample at the angles of 2θ: 34.44°, 36.25° and 47.54° which represents the hkl plane of (002), (101) and (102), respectively. The crystalline size calculated from XRD data is found to be in the range of 35-42 nm. The UV-Vis spectrum shows that Se-ZnO nanorods strong absorption peaks appeared in the range of 300-380 nm for all samples. Se doping has slightly altered the band gap energy of pure ZnO nanorods around 0.01 eV. The peak of the photoluminescence spectra of the sample at 470 nm indicates the blue emission band.

Synthesis, characterization and Rietveld refinement of AgBr@KNi [FeC6N6]0.7[CoC6N6]0.3/SiO2 nanocomposite

Abstract We report here the formation of nanocomposite of Bromargyrite doped in Prussian blue composite in the matrix of silica i.e. AgBr@KNi [FeC6N6]0.7[CoC6N6]0.3/SiO2. This was successfully synthesized by the wet chemical precipitation procedure. The as-prepared sample and sample sintered at 500, 700, 900, and 1100 °C were structurally analysed by XRD. The result of XRD and Rietveld Refinement showed that the as-prepared sample was converted into the AgBr@Fe2O3/SiO2. The refinements of the prepared samples were done by Fullprof Suite Software. With the Rietveld Refinement and XRD analysis, we achieved some microstructural and structural parameters like intensity, hkl planes, Wyckoff positions of atoms (x/a, y/b, z/c), size of the crystal, and R-factors (χ2, Rp, Rwp, Rexp). The size of crystal of as-prepared sample and AgBr@Fe2O3/SiO2 nanocomposite (1100 °C) was obtained as 3.89 nm and 34.64 nm respectively. The value of goodness fit factor was also achieved from the Rietveld Refinement.

An Investigation on Microstructural, Morphological, Optical, Photoluminescence and Photocatalytic Activity of WO3 for Photocatalysis Applications: An Effect of Annealing

The presence of carcinogenic dyes in industrial wastewater is a serious problem that hazards the water bodies and nano-catalysts are key members that are used to purify it. Therefore, this work investigates the synthesis of tungsten oxide (WO3) nanoparticles with various annealing temperatures in the range of 100–600 °C by the co-precipitation method for photocatalysis applications. The improvement in crystallinity of the nanoparticles achieved through annealing temperature and the crystallite size was an increase from 10 to 34 nm. The structural parameters of the prepared samples were characterized using XRD reveals the formation of stable monoclinic structure. FESEM morphological images confirmed the formation of irregularly shaped nanoplates. HRTEM and SAED patterns confirmed the growth of nanocrystalline WO3 nanoparticles. Parameters like (hkl) planes and interplanar spacing values obtained from HRTEM studies agreed well with the results of XRD. The elemental presence and chemical compositions were confirmed from EDS and XPS studies, respectively. The presence of functional groups has been verified through FTIR spectroscopy studies. Considerable decrements in the energy gap of WO3 NPs were observed with annealing from 2.89 to 2.61 eV. The defects/oxygen deficiencies were examined through photoluminescence. The photocatalytic performance of WO3 NPs was assessed by degrading the methylene blue dye. The parameters obtained from Pseudo first-order kinetic studies confirmed that 600 °C annealed WO3 NPs have higher photocatalytic activity.

Annealing Temperature Effect of ZnO Seed Layer on Integrated Photosupercapacitor Performance

Photosupercapacitor is an integrated device for harvesting and storing solar energy into electrical energy. Photosupercapacitor is constructed by solar cell and supercapacitor. In the solar cell with DSSC type, one of the influential variables is photoanode performance. The photoanode with ZnO layer plays a role in light absorption, charge mobility, and electrical properties, which are influenced by crystal structure and nanoscale morphology. One of nanoscale morphology of ZnO that widely used is nanorods. This work is focussed to investigate the effect of annealing temperature on seed layer ZnO to growth nanorods shape in photoanode of photosupercapacitor and its performance. The seed layer ZnO nanoparticle was deposited onto FTO substrate by a screen printing method. The ZnO nanorod was grown by dippin FTO/ZnO in solution (Zinc nitrate, HMT, and DI water) under 100 °C. The photosupercapacitor was constructed by DSSC and ZnO symmetric supercapacitor which integrated by using aluminum foil substrate. The annealing temperature on ZnO nanoparticles affected on increasing crystal size of ZnO seed. All of the samples show ZnO wurtzite phase with the highest peak located on the hkl plane (101), but ZnO nanorod growth to hkl plane (100). The DSSC part efficiency produced around 0.874%. The resulting efficiency of photosupercapacitor is around 0.549%. The annealing temperature causes the value of specific capacitance to decrease, because of decreasing DSSC performance.

High-performance solid state supercapacitors based on intrinsically conducting polyaniline/MWCNTs composite electrodes

The electrochemical behavior of the prepared solid state supercapacitors based on the composites of polyaniline (PANI) with multiwalled carbon nanotubes (MWCNTs) have been reported in this study. The PANI/MWCNTs composites are prepared by simple chemical oxidation polymerization method with different doping concentrations (2, 4, 6 and 8 wt%) of MWCNTs. X-ray diffraction studies performed on the pristine and composite samples reveal the semi-crystalline nature of PANI, with three well visualized reflections at 2θ values of 16, 22 and 25o, corresponding to the hkl planes (011), (020) and (200) respectively, of PANI. The absence of crystalline peaks of MWCNTs in the composites reveal the complete wrapping of PANI chains over the MWCNTs. Field emission scanning electron microscopy studies reveal the agglomerated structural form of the prepared samples. Raman spectroscopic studies confirm the growth of PANI and its composites with MWCNTs, consisting of all the characteristic bands of PANI. The electrochemical activity of the prepared supercapacitor is recorded through cyclic voltammetry. The prepared supercapacitor with 8 wt% doping concentration of MWCNTs, has significantly high values of 446.89 F/g, 248.29 Wh/kg and 16,865.12 W/kg for the specific capacitance, energy density and power density, respectively. The high values of these parameters for the supercapacitor with 8 wt% doping concentration of MWCNTs can be attributed to the high electrical conductivity, low internal resistance and inherent porous nature of MWCNTs. The PANI-MWCNTs composites have more stability with capacitance retention of 83.97% for PANI/MWCNTs composite (8 wt%), whereas, pristine PANI exhibits only 64.12% of the original capacitance after 10,000 cycles and the stability increases with the increase in doping concentration of MWCNTs.

Optical sensing of hydrogen peroxide using starch capped silver nanoparticles, synthesis, optimization and detection in urine

Silver nanoparticles were synthesized using starch as a capping shell, AgNO3 as a source of silver and sodium borohydride (NaBH4) as a reducing agent. The nanoparticles were confirmed by their localized surface plasmonic resonance (LSPR) Ultraviolet-visible (UV–Vis) absorbance at 403 nm. Dynamic light scattering (DLS) reveals that starch capped silver nanoparticles (SAgNPs) mean size were 4.13 nm/diameter; the structure of SAgNPs was identified as face-centered cubic (FCC) using XRD analysis. HRTEM micrograph and contrast intensity profile confirms Ag atomic lattices at a distance of 2.35 Å and 2.03 Å corresponding to (111) and (200) hkl plane. The scope of SAgNPs to detect hydrogen peroxide (H2O2) in aqueous media and in urine samples was investigated. Volumes of SAgNPs, pH, temperature and time effect were used as parameters to optimize the detection of H2O2. The SAgNPs assay was compared with a commercially available assay kit. Linear responses were obtained with slopes and regression factors of (0.1025; r2=0.9883) and (0.0776; r2=0.9940) for SAgNPs and the assay kit respectively. Limit of detection (LOD) of 3.70 µM was obtained in the 0.45–121 µM range while, a LOD of 10.5 nM was obtained in the 4.70–32.0 nM range for the SAgNPs test. Values in the range of (9.22 ± 0.30 – 17.89 ± 0.28) and (8.43 ± 0.06 – 26.81 ± 0.19) μM of H2O2 were assessed by using SAgNPs and assay kit respectively, in urine samples collected from seven apparently healthy men aged between 20 and 40 years old.

Synthesis and characterization of CZTS thin films from compound target deposited by RF sputtering method

A potential way to improve the quality of Copper-Zinc-Tin-Sulfide (Cu2ZnSnS4(CZTS) absorber thin film by one step process of Radio Frequency (rf) sputtering using a single compound target is proposed for thin film solar cells. Structural and Optical characterizations were carried out using X-ray Diffractometer, Raman spectrophotometer and UV-VIS spectrophotometer. The X-ray diffraction analysis showed hkl planes of (002), (110), (112) and (212). Raman results confirmed the existence of secondary phases of SnS, Cu2-xS and CTS. The optical absorption coefficient of the thin film was found to be greater than 104cm−1 indicating a direct band gap nature of the samples. The optical band energy was calculated and found to be in the range of 1.51eV to 2.4 eV. The band gap energy obtained is more appropriate for photovoltaic applications.

Development of a Stress Sensor for In-Situ High-Pressure Deformation Experiments Using Radial X-Ray Diffraction

We developed a stress sensor for in-situ deformation experiments using synchrotron radial X-ray diffraction. This stress sensor provided nearly diffraction-plane-independent stress that, when used in series with a sample, reduced the uncertainty of the average stress estimation acting on a sample. Here, we present the results of a study where pyrope was used as a stress sensor. Using a Deformation-DIA (D-DIA) high-pressure deformation apparatus, pyrope, olivine and alumina were deformed in the same run/cell assembly placed in series along the compression direction. Deformation experiments were conducted at pressures between 4 and 5 GPa and temperatures between 730 and 1273 K with strain-rates between 10−5 and 10−6 s−1. Stresses estimated from various (hkl) planes in pyrope were nearly the same; i.e., pyrope is plastically isotropic with ≤10 % variation with (hkl). However, stresses from various (hkl) planes in olivine and alumina varied by approximately a factor of 3. Comparisons between average stresses inferred from pyrope and those from different diffraction planes in olivine and alumina showed that the average stress in these materials evolved from low-end stress, estimated from various (hkl) planes at small strain, to high-end stress at a large strain. This suggests that the rate-controlling slip system in these materials changes from the soft to the hard slip system with strain.

Surface plasmon resonance effect of Ag metallized SnO2 particles: Exploration of metal induced gap states and characteristic properties of Ohmic junction

Ag metallization on the surface of SnO2 catalyst was performed by the photoreduction method, and its presence was confirmed by the (111), (200), (220), and (311) hkl planes of Ag metal by powder X‐ray diffraction technique. Further lattice parameters “a” and “c” of the SnO2 tetragonal unit cell show prominent changes on metallization. Ultraiolet‐visible absorption spectrum of Ag‐SnO2 shows the extended adsorption in the visible region up to almost ~565 nm due to the surface plasmon resonance (SPR) effect. Percentage composition of the elements present in the SnO2 and Ag‐SnO2 samples were confirmed by the energy‐dispersive X‐ray analysis and the inductively coupled plasma‐atomic emission spectroscopic analysis techniques, and the spherical morphology of these samples were confirmed by the scanning electron microscopy. The photoluminescence technique confirms the reduction of recombination of photogenerated charge carriers by 44% in the case of Ag‐SnO2. The metal‐metal oxide contact was found to be Ohmic rather than Schottky. The higher activity of the Ag‐SnO2 nanoparticles are correlated to the SPR effect, metal‐induced gap states, inherently created structural defects, the ability of Sn to show multiple oxidation states, variation in the surface oxygen concentration, and also to the Ohmic junction. Synergistic effect between electronic/intrinsic defect energy levels of Ag‐SnO2 photocatalyst with the redox potential of the fast red dye leads to the higher quantum efficiency.

Sb doping influence on structural properties of ZnO thin films

Pure and Sb doped ZnO thin films were homogeneously prepared at room temperature on the soda-lime glass substrates (SLG) via the spin coating technique. The effects of the Sb ratio on structural properties, morphological properties and optical properties were studied via x-ray diffraction (XRD) device, scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) spectrometry, respectively. Crystalline size (D), the (hkl) planes, and dislocation density (δ) for ZnO thin films were investigated via the XRD pattern. The influence of Sb doping on the preferred crystal orientation and lattice parameters of ZnO thin films were discussed in detail. Optical measurements of ZnO thin films with 0, 1, 2 and 3% Sb concentrations showed a significant effect as a function of Sb dopants on the optical energy band gap. All of the SEM images indicated that while pure ZnO thin films had an apparent nanofiber structure, nanofiber structures disappeared with the increase of doping ratio, and more homogeneous films were obtained.

Spectral, dielectric, mechanical and optical characteristics of LPDMCl single crystal for nonlinear optical applications

A potent semiorganic third order acentric crystal Poly[μ-chlorido-heptachlorido-μ3-l-proline-μ2-l-proline-tetramercury(II)] (LPDMCl) with the chemical formula [Hg4Cl8(C5H9NO2)2]n was crystallized by slow evaporation in water and thereby its second and third order optical nonlinearities are explored using the technique of SHG powder test of Kurtz-Perry and Z-scan single beam respectively. The grown crystalline material was analyzed by single crystal XRD, which discloses the acentric space group P1 of the material with the crystal system of triclinic. From XRD analysis, the obtained peaks were indexed correlated to the orientations of (hkl) plane thus displaying the crystalline purity and perfection. FTIR spectrum detailed the diverse vibrational modes, which signifies the functional groups in LPDMCl. Surface topology of the crystallized salts was accomplished by the examination of SEM. Mechanical, dielectric, linear and nonlinear optical investigation were performed to affirm LPDMCl as an aspiring candidate in establishing proficient nonlinear optical and optical power limiting device for practical applications.

Efficient UV photodetectors based on Ni-doped ZnS nanoparticles prepared by facial chemical reduction method

Ni-doped ZnS nanoparticles are synthesized by simple hydrothermal process for the utilization in UV photodetectors. Surface morphology of the prepared samples is investigated through high resolution transmission electron microscopy (HRTEM), which reveals that the prepared nanoparticles are smaller than 20 nm. The well visualized selected area electron diffraction rings suggests the nanocrystalline nature of the prepared nanoparticles with (hkl) planes (111), (220) and (311). The structural analysis is done by x-ray diffraction (XRD) studies; which reveal the decrease in crystallite size with increase in Ni-doping concentration. The device performance of the photodetectors is tested under UV-A light (wavelength ≈365 nm) and found that the ability of the prepared devices increases with increase in Ni-doping concentration. This can be attributed to the enhanced surface to volume ratio and increase in charge carrier concentration. The adsorption-desorption of oxygen molecules on the nanoparticles' surface is considered to be the mechanism for UV photodetection.

Planar Heterojunction Solar Cell Employing a Single-Source Precursor Solution-Processed Sb2S3 Thin Film as the Light Absorber.

We discuss here a solution-processed thin film of antimony trisulphide (Sb2S3; band gap ≈ 1.7 eV; electronic configuration: ns2np0) for applications in planar heterojunction (PHJ) solar cells. An alternative solution processing method involving a single-metal organic precursor, viz., metal–butyldithiocarbamic acid complex, is used to grow the thin films of Sb2S3. Because of excess sulphide in the metal complex, the formation of any oxide is nearly retarded. Sb2S3 additionally displays structural anisotropy with a ribbon-like structure along the [001] direction. These ribbon-like structures, if optimally oriented with respect to the electron transport layer (ETL)/glass substrate, can be beneficial for light-harvesting and charge-transport properties. A PHJ solar cell is fabricated comprising Sb2S3 as the light absorber and CdS as an ETL coated on to FTO. With varying film sintering temperature and thickness, the typical ribbon-like structures predominantly with planes hkl: l = 0 stacked horizontally along with respect to CdS/FTO are obtained. The morphology of the films is observed to be a function of the sintering temperature, with higher sintering temperatures yielding compact and smooth films with large-sized grains. Maximum photon to electricity efficiency of 2.38 is obtained for PHJ solar cells comprising 480 nm thick films of Sb2S3 sintered at 350 °C having a grain size of few micrometers (>5 μm). The study convincingly shows that improper grain orientation, which may lead to nonoptimal alignments of the intrinsic structure with regard to the ETL/glass substrate, is not the sole parameter for determining photovoltaics performance. Other solution-processing parameters can still be suitably chosen to generate films with optimum morphology, leading to high photon to electricity efficiency.