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Group-IV monochalcogenides have recently shown great potential for their thermoelectric, ferroelectric, and other intriguing properties. The electrical properties of group-IV monochalcogenides exhibit a strong dependence on the chalcogen type. For example, GeTe exhibits high doping concentration, whereas S/Se-based chalcogenides are semiconductors with sizable bandgaps. Here, we investigate the electrical and thermoelectric properties of gamma-GeSe, a recently identified polymorph of GeSe. gamma-GeSe exhibits high electrical conductivity (~106 S/m) and a relatively low Seebeck coefficient (9.4 uV/K at room temperature) owing to its high p-doping level (5x1021 cm-3), which is in stark contrast to other known GeSe polymorphs. Elemental analysis and first-principles calculations confirm that the abundant formation of Ge vacancies leads to the high p-doping concentration. The magnetoresistance measurements also reveal weak-antilocalization because of spin-orbit coupling in the crystal. Our results demonstrate that gamma-GeSe is a unique polymorph in which the modified local bonding configuration leads to substantially different physical properties.

We report on the fabrication of TiO2 nanospheres (NSs) monolayer arrays for enhancement of light extraction quantum efficiency of GaN-based light-emitting diodes (LEDs). The fabricated TiO2 NSs monolayer arrays composed of different phases of anatase (An-) and amorphous (Am-) TiO2, the arrays were transferred onto the topmost layer of LED chips via facile icing transfer method. The LED chips covered with Am-TiO2 NSs monolayer arrays shows 3.0- times enhanced light output power intensity compared with reference LED chips at a fixed injection current of 100 mA. The enhanced light extraction of LED chips by Am-TiO2 NSs monolayer can be attributed to an high transmittance (91.1%) in visible and increased light extraction probability of photons generated in LEDs, resulting from the enhanced light coupling efficiency by reduced total internal reflection (TIR). Finite-difference time-domain (FDTD) simulation results also agreed well with the experimentally observed results. Based on the experimental and theoretical results, our suggested Am- and An-TiO2 NSs arrays can be considered as a very facile and effective method to improve the device performance of various visible LEDs chips.

Scanning transmission electron microscopy (STEM) is an indispensable tool for atomic-resolution structural analysis for a wide range of materials. The conventional analysis of STEM images is an extensive hands-on process, which limits efficient handling of high-throughput data. Here, we apply a fully convolutional network (FCN) for identification of important structural features of two-dimensional crystals. ResUNet, a type of FCN, is utilized in identifying sulfur vacancies and polymorph types of MoS

Scanning transmission electron microscopy (STEM) is an indispensable tool for atomic-resolution structural analysis for a wide range of materials. The conventional analysis of STEM images is an extensive hands-on process, which limits efficient handling of high-throughput data. Here we apply a fully convolutional network (FCN) for identification of important structural features of two-dimensional crystals. ResUNet, a type of FCN, is utilized in identifying sulfur vacancies and polymorph types of ${MoS_2}$ from atomic resolution STEM images. Efficient models are achieved based on training with simulated images in the presence of different levels of noise, aberrations, and carbon contamination. The accuracy of the FCN models toward extensive experimental STEM images is comparable to that of careful hands-on analysis. Our work provides a guideline on best practices to train a deep learning model for STEM image analysis and demonstrates FCN's application for efficient processing of a large volume of STEM data., 24 pages, 5 figures

In this paper, we report a one-step, sunlight-irradiated synthesis of ZnO nanostructures (NSs) covered with Ag nanoparticles (NPs) using Tamarindus indica pulp extract (TPE) and their applications to photocatalytic and antibacterial activity. TPE contains phytochemicals that act as reducing and stabilizing agents for the distribution of uniform Ag NPs of approximately 5 nm on the surface of ZnO NSs. The photocatalysis of the synthesized bare ZnO and ZnO/Ag (0.5 wt%) NSs was evaluated under UVA light and dye degradation results for methylene blue (MB) are 68% for ZnO and 94% for ZnO/Ag after 120 min. For methylene orange (MO), bare ZnO and ZnO/Ag NSs were degraded 40% and 81%, respectively, after 150 min. Moreover, the photocatalyst also showed good recycling stability even after five cycles. In addition to dye degradation, the ZnO/Ag NSs were able to show antibacterial activity against E. coli, P. aeruginosa, S. aureus, and B. subtilis at a concentration of 2 mg/ml. They showed higher activity against Gram-positive than gram-negative bacteria, which showed the influence of Ag metal on the enhanced photocatalytic and antibacterial activity of ZnO NSs. Our findings suggested that ZnO/Ag NSs can be synthesized by a facile and ecofriendly method using TPE and showed superior performance for UVA photocatalysis and antibacterial activity compared to bare ZnO.

Advanced oxidation processes triggered by nanoscale materials are promising owing to the in-situ generation of reactive radicals that can degrade toxic organic pollutants. In the present study, zinc sulfide (ZnS) nanoparticles with polyethylene glycol-4000 (PEG-4000) and polyvinylpyrrolidone (PVP) cappings were prepared using the chemical precipitation method and characterized thoroughly. Optical and structural characteristics of the capped ZnS nanoparticles were investigated and compared with those of uncapped ZnS nanoparticles. Results showed that PVP and PEG capped ZnS nanoparticles exhibited smaller crystallite size of 1.42 and 1.5 nm, respectively, as compared to uncapped ZnS (1.93 nm). Consequently, band gap energies of capped ZnS nanoparticles were higher which enable them to work as solar photocatalyst. The photocatalytic performance of the PEG, PVP-capped, and uncapped ZnS nanoparticles were evaluated against methyl orange (MO) dye and showed 85%, 87%, and 80% dye removal efficiencies, respectively. Degradation rate constant derived using Langmuir-Hinshelwood model revealed faster degradation kinetics bycapped ZnS photocatalysts owing to broader light absorption range. A possible dye degradation mechanism based on the energy levels positions was proposed to explain the route of photocatalytic degradation of MO by ZnS materials. It was inferred that the generation of reactive oxygen species by photogenerated electron-hole pairs facilitate degradation of MO dye molecules under sunlight illumination. It is expected that this work will provide insights into the development of strategies employed to achieve enhanced photocatalysis by nanoscale materials through organic capping.

A series of calcium oxide–magnesium oxide (CaO–MgO) catalysts were prepared under the effects of different precipitating agents and using varied Mg/Ca ratios. The physiochemical characteristics of the prepared catalysts were analyzed using XRD, FE-SEM, BET, FTIR, and TG/DTA techniques. Quantification of basic active sites present on the surface of the CaO–MgO catalysts was carried out using the Hammett indicator method. The as-prepared mixed oxide samples were tested for propylene carbonate (PC) synthesis through the alcoholysis of urea with propylene glycol (PG). The effects of the catalyst composition, catalyst dose, reaction temperature, and contact time on the PC yield and selectivity were investigated. The maximum PC yield of 96%, with high PC selectivity of 99% and a urea conversion rate of 96%, was attained at 160 °C using CaO–MgO catalysts prepared using a Mg/Ca ratio of 1 and Na2CO3 as a precipitating agent. The best-performing catalysts also exhibited good reusability without any significant loss in PC selectivity. It is expected that the present study will provide useful information on the suitability of different precipitating agents with respect to the catalytic properties of the oxides of Ca and Mg and their application in the synthesis of organic carbonates.

Partial phase modification of zinc hydroxystannate (ZHS) is an effective technique for improving its light absorption capacity. In this study, a zinc hydroxystannate/zinc-tin oxide (ZHS/ZTO) heterostructure was synthesized via chemical co-precipitation followed by annealing. The as-prepared heterostructure revealed cubic crystal morphology along with high-intensity diffraction peaks in the XRD pattern. The XPS analysis of ZHS/ZTO heterostructures demonstrated the presence of key elements (Zn, Sn, and O) in their most stable ionic forms. The photocatalytic degradation efficiencies of the prepared samples were tested against methyl orange (MO) and tetracycline (TC) in an aqueous medium under UVC (254 nm) radiation. Under optimized conditions, maximum degradation efficiencies of 99% for MO and 97% for TC were observed in 120 and 180 min, respectively. Further, the predominant role of OH˙ radicals in the photocatalytic removal of MO and TC was evident through scavenging experiments. 2nd order kinetic model was outperformed in simulating the degradation mechanism of both targets over 1st and zero-order kinetic models. Finally, a photocatalytic degradation mechanism is proposed based on the energy values estimated for the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) using UPS analysis.

Although ZnO nanostructure-based photodetectors feature a well-established system, they still present difficulties when being used in practical situations due to their slow response time. In this study, we report on how forming an amorphous SnO2 (a-SnO2) shell layer on ZnO nanorods (NRs) enhances the photoresponse speed of a ZnO-based UV photodetector (UV PD). Our suggested UV PD, consisting of a ZnO/a-SnO2 NRs core–shell structure, shows a rise time that is 26 times faster than a UV PD with bare ZnO NRs under 365 nm UV irradiation. In addition, the light responsivity of the ZnO/SnO2 NRs PD simultaneously increases by 3.1 times, which can be attributed to the passivation effects of the coated a-SnO2 shell layer. With a wide bandgap (~4.5 eV), the a-SnO2 shell layer can successfully suppress the oxygen-mediated process on the ZnO NRs surface, improving the photoresponse properties. Therefore, with a fast photoresponse speed and a low fabrication temperature, our as-synthesized, a-SnO2-coated ZnO core–shell structure qualifies as a candidate for ZnO-based PDs.

Metal–semiconductor–metal UV photodetectors consisting of transferable zinc-tin-oxide (ZTO) microsphere (MS) monolayers with different phases and sizes are reported. From the experimental results, the crystallized Zn2SnO4 (c-ZTO)-MS-monolayer-based photodetectors present higher performance than amorphous ZnSnO3 (a-ZTO)-based photodetectors. The external quantum efficiencies of the a-ZTO- and c-ZTO-MS-based UV photodetectors are 16.7% (at 320 nm) and 580.9% (at 310 nm), respectively. Moreover, the UV-to-visible rejection ratios of the a-ZTO and c-ZTO are 20 (320 nm/400 nm) and 1484 (310 nm/400 nm), respectively, indicating that both fabricated ZTO MS UV photodetectors present great visible-blind properties. To further improve the optoelectronic device performance, the c-ZTO-MS-based UV photodetector is optimized using various sphere diameters, namely, 0.79, 0.99, 1.24, and 1.51 μm. The best photodetecting properties are obtained for the 1.24 μm c-ZTO MS detector, showing a 51.1-fold improvement in photocur...

We report the efficient biogenic synthesis of silver nanoparticles (Ag NPs) using silver nitrate and extracts of different parts of Theobroma cacao: the husk (h-Ag NPs), pulp (p-Ag NPs), and seed (s-Ag NPs). In addition, we have tested the antibacterial and photocatalytic activities of the Ag-NPs. The Ag NPs obtained from husk, pulp, and seed extracts show variation in the particle size, dispersion, and morphology. UV–visible absorbance measurements reveal surface plasmon resonance bands at 425, 438, and 462 nm for the s-Ag, h-Ag, and p-Ag NPs, respectively. Transmission electron microscopy studies revealed the formation of monodisperse spherical Ag NPs with diameter ranging from 6 to 18 nm. Fourier transform infrared measurements of the as-synthesized Ag NPs indicate differences in the phytochemicals decorating the NP surfaces, which led to differences in the zeta potential, hydrodynamic radius, and polydispersity index. The p-Ag, h-Ag, and s-Ag NPs exhibited photocatalytic activity on exposure to sunlight from sun, achieving 35%, 29%, and 24% degradation of methylene blue (MB) within 60 min, respectively. Further, the p-Ag NPs showed 98.3% MB photodegradation after 180 min. The photocatalytic rate constants for the degradation of MB were also calculated. Finally, we found that the biogenic nanoparticles affect bacterial growth, possibly by causing protein leakage and cell death. The p-Ag NPs showed better antibacterial activity against Bacillus subtilis and Escherichia coli than h-Ag and s-Ag. The photocatalytic and antibacterial activities of the Ag NPs synthesized with T. cacao mainly depend on the particle size and the biomolecules on the surface of the NPs.

Ag@CuO core shell nanostructures (ACCS NSs) was successfully synthesized using Ocimum tenuiflorum leaf extract when applied for non-enzymatic glucose sensor. SEM, HR-TEM, XRD, UV–vis, and FTIR were used to estimate the structural, optical and morphological properties of ACCS NSs. Cyclic voltammetry and ampherometry were used to determine the electrochemical and electrocatalytic characteristics of 0.2 wt% ACCS NSs with screen-printed electrodes (SPEs) to sense glucose in 0.1 M NaOH solution. Optimum potential was obtained at + 0.4 V of current response with a linear range of 1 to 9.2 mM. In addition, 0.2 wt% ACCS NSs with SPEs had a low detection limit of 0.006 μM and sensitivity of 3763.44 μA mM−1 cm−2. Modified ACCS/SPE electrodes were highly selective for glucose in the presence of chlorine ions, sugars and non-sugar compounds. It could be inferred from the evidence that the ACCS NSs performs effectively in the aspect of non-enzymatic glucose sensing.

The emergence of multidrug-resistant

In this study, we investigated the effects of InGaN/GaN-based interlayer (IL) and electron emitting layer (EEL) consisting of a GaN barrier layer grown with different metal-organic (MO) precursors of gallium (Ga), which were grown underneath the active layer. The growth behavior of GaN with triethyl Ga (TEGa) showed an increasing growth time due to a lower growth rate compared with GaN grown with trimethyl Ga (TMGa), resulting in the formation of columnar domains and grain boundary with reduced defect. UV-A light emitting diode (LED) chips with three types of ILs and EELs, grown with different MO sources, were fabricated and evaluated by light output power (LOP) measurements. The LOP intensity of UVLED-III with the GaN barrier layer-based IL and EEL grown by TEGa was enhanced by 1.5 times compared to that of the IL and EEL grown with TMGa at 300 mA current injection. Use of the GaN barrier layer in ILs and EELs grown by TEGa improved the crystal quality of the post grown InGaN/GaN multiple quantum well, which reduces leakage current. Therefore, for the UV-A LED with ILs and EELs grown with TEGa MO precursors, electrical and optical properties were improved significantly.

Not long ago, new industrial products were developed using fungal secondary metabolites. Fungi have numerous secondary metabolites such as terpenoids, xanthones, steroids, phenols, chinones, tetralones, cytochalasins, enniatins, benzopyrones, flavonoids, alkaloids, cardiac glycosides, tannins, and saponins. In recent years, cancer has become a dreadful disease all over the world, and more than 6 million new cases are reported every year. Fungi have tremendous chemical diversity, and they also play important roles in the development of numerous clinically useful anticancer agents. The productivity and vulnerability of novel metabolites from microorganisms make them essential, readily available, renewable, and everlasting sources of novel structures bearing pharmaceutical potential. Shrewdness from fungal research could provide substitute methods of natural product drug discovery that could be reliable, economical, and environmentally safe.

We report on the application of graphene (Gr)/copper (Cu) shell/core nanowires (NWs) as a transparent conducting electrode (TCE) for optoelectronic devices. First, we optimize the synthesis conditi...

An enzyme-free glucose sensor developed based on silver nanoparticles (Ag NPs) via bio-mediated route using Ocimum tenuiflorum leaves extract. The Ag NPs were characterized by X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Particle size analyzer (PSA), Scanning electron microscopy (SEM), Energy-dispersive X-ray (EDAX) spectroscopy, and Transmission electron microscopy (TEM), to study structural, optical and morphological properties. The electrocatalytic activity of Ag NPs towards the oxidation of glucose in the 0.1 M NaOH electrolyte solution was analyzed. The Ag NPs was coated on Glassy carbon electrode (GCE) and reports indicating the outstanding capability such as high sensitivity (895.8 μAmM−1cm−2), linear range (1–8.9 mM), response time (

We report on the formation of transferable microspheres monolayers consisting of ZnSnO3 (ZTO) synthesized via fast ethanol precipitation and their application to GaN-based light-emitting diodes (LEDs) to improve device performance. ZTO microspheres with diameters of 820 ± 20 nm (ZTO-1), 910 ± 10 nm (ZTO-2), and 1200 ± 10 nm (ZTO-3) were synthesized and arrayed to form a monolayer using polydimethylsiloxane (PDMS) and a unidirectional rubbing method. ZTO-1, ZTO-2, and ZTO-3 monolayers exhibited optical transmittance percentages of 94.4%, 92.98%, and 87.09% at 450 nm, respectively. Effects of ZTO monolayers on the light extraction efficiency of LEDs were evaluated using LED chips sized 800 μm × 800 μm. LEDs with a ZTO-3 monolayer as a top layer had a light extraction efficiency of ∼144%, relative to regular LEDs, as well as improved electrical properties, as evidenced by a decrease in Vturn on of ∼0.6 V and a decrease in Ron by 0.036 kΩ. XPS analysis indicated that the improvement in the electrical properti...

We demonstrate the green light-emitting diodes (LEDs) using n-In2O3 nanorods (NRs)/p-GaN based pn junction with an insertion of thin Ga2O3 layer. In order to form the oxide interfacial layer between n- and p-material, O2 plasma treatment was conducted on p-GaN surface. The X-ray photoelectron spectroscopy patterns clearly show the formation of thin Ga2O3 layer on p-GaN surface via O2 plasma treatment. After formation of Ga2O3 layer on p-GaN surface, water droplet contact angle is decreased from 55° to 39°, which means that the surface is converted toward to more hydrophilic properties. The In(OH)3 NRs with 300 nm-length and 150 nm-diameter are uniformly grown on plasma treated p-GaN surface by using hydrothermal method. After then, final In2O3 NRs were obtained by phase change from as-grown In(OH)3 NRs without the morphology change by calcination process. The electroluminescence of fabricated LEDs using n-In2O3/Ga2O3/p-GaN heterojunction shows the green emission (λ ∼ 554 nm) at forward bias condition. As a possible light emission mechanism from our suggested heterostructures, the various defects energy states mediated green emissions were considered with band diagram.

Research based on ZnO as a potential candidate in solar cells continues to draw greater attention as it provides an interlink between nanoparticles and improves the efficiency of electron transport towards the transparent conducting oxide electrode by reducing the recombination rate with holes. In the present investigation, ZnO paste is prepared using the solid-state synthesis technique. The preparative protocol was optimized by a screening of various precursor materials to get a smooth and viscous paste. The binder-free protocol is the key to successful paste preparation. The preliminary approach is the preparation of the ZnO paste mixture and its deposition on FTO substrate by doctor blade technique using a binder. The paste of ZnO with Indium, Tin doped paste was utilized without using the additional binder. Device tests of experimental DSSCs were performed with dye D149. The overall power conversion efficiency of the optimized ZnO-based DSSC reaches 1.16% and increases to 4.26% after the Sn doped ZnO. Indium doped ZnO DSSC shows 3.41% power conversion efficiency.

We report on the formation of a pn junction through the use of CuO/Cu1-xInxO core/shell nanowire (NW) structures for application in photodetectors. The CuO NWs arrays were prepared by simple heat-treatment of Cu foil at 500 °C in ambient air in a furnace. The Cu1-xIn xO nanocomposites synthesized by reflux condensation were drop-casted onto prepared p-CuO NWs arrays to form a core/shell pn junction. Investigation of Cu1-xInxO nanocomposites containing differing amounts of In2O3 (from pure CuO nanocomposites to nanocomposites including 80% In2O3) exhibits the changed electrical polarity that varies from p-type to n-type. Following the formation of the indium tin oxide (ITO) electrode on the Cu1-xIn xO shell surface, the observed current–voltage (I–V) curves clearly showed typical rectifying p-n diode characteristics. Our suggested p-n heterojunction yielded a 3.48-fold increase in photocurrent level upon Xe lamp illumination when compared with current in the dark state. Additionally, the fabricated core/shell p-n junction exhibited a photoresponsivity of 0.045 A/W at 374 nm.

We report the control of structural, optical, and electrical properties of solution processed copper (Cu) nanowires (NWs) by varying the capping agent concentration and demonstrating the enhanced light extraction of GaN-based light-emitting diodes (LEDs) using Cu NWs. Cu NWs were prepared by a simple solvothermal method, and the capping agent concentration effects on the growth of Cu NWs were systematically investigated. The different diameters of Cu NWs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible absorption, and conductivity measurements. All characterization results showed high aspect ratio nanowires with efficient transmittance and conductivity properties. When the synthesized Cu NWs were adopted as a transparent conducting layer, the electroluminescence intensity was improved by its spreading effects. This work will elucidate the influence of capping agents on the physical properties, optical properties, and electrical conductivity of Cu NWs for use as a transparent conductor in optoelectronic devices. Keywords: Copper nanowire, Capping agent, Transparent conductor, Light emitting diode

The structure, morphology and chemical doping in metal oxide are important factors that can influence on its photocatalytic activity. In this work, a facile and template free reflux method has been used to synthesize ZnO nanostructures for the morphology control of cubes, maize corn seeds, and rods at low temperature. The photocatalytic activity of ZnO with different morphology was evaluated towards degradation of methyl orange under UV light illumination. Among all the morphology controlled ZnO, the maize corn seed shaped ZnO shows the superior photocatalytic activity. Moreover, the influence of Cu contents on the structural, optical, and photocatalytic activity of ZnO maize corn seed was also investigated systematically. The photocatalytic experiment towards the degradation of methyl orange revealed that the 0.5 mol% Cu doped ZnO exhibits 3.5 fold higher photocatalytic activity than pure corn seed shaped ZnO. The enhancement of photocatalytic activity by Cu ions substituting in ZnO lattices is attributed to synergetic effect of Cu and ZnO, increase the separation of photogenerated electron-hole pairs, oxygen vacancy, decrease in crystallite size and the higher surface to volume ratio. Based on scavengers test, it was found that both superoxide and hydroxyl radicals are mainly actives species involved for the degradation of methyl orange.

Environment-friendly photocatalysts under sunlight with wide spectral responses for wastewater treatment are currently an exciting area of research. Herein, we report the synthesis of Sn doped N-TiO2 nanoparticles with different contents of Sn by a greener microwave assisted method. The phase purity, morphology, particle size, optical properties, and elemental composition were systematically analyzed by various sophisticated analytical techniques. The X-ray diffraction (XRD) patterns revealed Sn doped N-TiO2 nanoparticles in the anatase phase. The shift of XRD peaks observed at lower angle and the XPS results indicate the successful doping of Sn4+ in the lattice of N-TiO2. The optical absorption edges of Sn-doped N-TiO2 showed an obvious red shift that plays a crucial role in the photocatalytic activity under abundant sunlight. We further explored Sn doped N-TiO2 for photodegradation of methyl orange (MO) and Zopiclone (Z-class drug) under sunlight irradiation. A maximum of 95% and 91% of MO and Zopiclone were photodegraded over 0.25% Sn doped N-TiO2 under sunlight within 80 and 120 min, respectively, which is ∼7-fold higher than bare N-TiO2. The enhanced photocatalytic activity could be attributed to combined effects of reduced crystallite size, suppressed recombination rate of photogenerated electron-hole pairs, and increased optical absorption towards visible light that establish their impending use to treat polluted water. The possible mechanism for high photocatalytic activity of Sn doped N-TiO2 has also been discussed.

In the present work, we report the photoresponse characteristics of the hybrid heterojunction consisting of polypyrrole (PPy) sandwiched between p-Si substrate and n-Cu x In 1−x O film. Experimental results revealed that the PPy interlayer influence the electronic conduction through the hybrid heterojunction. Structural analysis by X-ray diffraction showed the diffraction peaks corresponding to CuO and In 2 O 3 , while the optical absorption spectra exhibited strong absorption in both the UV as well as visible regions. Morphological analysis by scanning electron microscopy showed the uniform coverage on the Si substrate, and the effective binding of Cu x In 1−x O and PPy. Raman spectroscopy showed the vibration modes corresponding to CuO, In 2 O 3 and PPy. The p-Si/PPy/n-Cu x In 1−x O hybrid heterojunction demonstrated excellent rectifying behavior and improved electrical characteristics such as high rectification ratio (∼220), lower threshold voltage (∼1.8 V) and ideality factor (∼2.06) due to the PPy insertion and photon illumination. The enhanced electrical characteristics of the hybrid p-Si/PPy/n-Cu x In 1−x O heterojunction was discussed with respect to the energy band structure, and found that the intermediate PPy layer acting as a hole transporting layer improves the charge selectivity and facilitates the effective transport of charge carriers towards the respective electrodes.

Highly uniform, petal-like, 3D-structured Ba3(PO4)2 phosphors were fabricated by facile wet chemical aqueous solution route. The production mechanism of Ba3(PO4)2 petal structure was optimized using XRD and SEM analysis grown under various temperatures and reaction times. Phase transition of Ba3(PO4)2 from the hexagonal to rhombohedral occurred with increasing reaction temperature. The Rietveld refinement based XRD phase analysis demonstrated the successful formation of monophase Ba3(PO4)2. Later, Ba3(PO4)2 was doped with various amounts of Sm3+ ions and with charge balance by Li+ ions. Ba3(PO4)2: Sm3++Li+ samples at 0.06 mol of Sm3+ concentration displayed maximum luminescence intensity in response to 402 nm excitation. Increasing the Sm3+ content over the 0.06 mol, emission quenching behavior was observed and it was explained by Dexter’s theory. The chromaticity coordinates of the Ba3(PO4)2:Sm3++Li+ phosphor material were calculated to be (0.5558, 0.4380), suggesting that it will be a potential yellow phosphor for use in W-LEDs in combination with blue LEDs chips.

This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (NRF-2015R1A1A1A05027848). K. Kim was supported by the Occasional Technology Development Project for Industrial Site Core Technology of the Ministry of Trade, Industry and Energy (No. 10054694).

This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (NRF-2015R1A1A1A05027848).

Metallic copper is a dependable co-catalyst for improving photoactivity of TiO2 photocatalysis. Cu@TiO2 core shell nanowires (NWs) were prepared by wet chemical synthesis and characterized. The microscopy images clearly show core shell morphology in nano regime. X-ray diffraction studies reveal the metallic copper and anatase TiO2 crystallinity. The optical absorption spectra exhibit ultraviolet and visible light harvesting properties. X-ray photoelectron spectroscopy confirms the presence of oxidation states of metallic copper and titanium. The photocatalytic efficiency was investigated by degrading the methyl orange (MO) and 3 wt% Cu@TiO2 core shell NWs shows highest degradation rate (k=0.02905 min−1) with superior photocatalytic activity. This material could be surely meet the necessities to harvest solar energy for many energy-related applications.

In the present work, we report on the fabrication and detailed electrical characterization of p-Si/n-Cu x In 1−x O heterojunction prepared via the deposition of nanocrystalline Cu x In 1−x O thin films on p -type silicon substrate by sol-gel method using spin coating technique. X-ray diffraction and Raman spectroscopy results revealed the polycrystalline nature of Cu x In 1−x O thin films consisting diffractions peaks and vibration modes, respectively, corresponding to CuO and In 2 O 3 . Field-emission scanning electron microscopy showed compact surface morphology while UV–vis absorption spectra exhibited sharp absorption between 300 and 425 nm along with a long tail extending in the visible region. The current-voltage (I-V) characteristics of the fabricated heterojunction demonstrated obvious rectifying behavior in the dark and under illumination. The heterojunction exhibited low reverse leakage current (~10 −7 ), and upon illumination, the forward current and rectification ratio of the junction was improved while the forward threshold voltage lowered. By fitting the experimental data we have observed that the forward current conduction is dominated by the space charge limited current mechanism.