Bebeh W. Nuryadin

A red emitting of manganese-doped boron carbon oxynitride (BCNO) phosphor materials: facile approach and photoluminescence properties

BCNO (boron carbon oxynitride) phosphors have attracted attention due to their non toxicity, simple synthesis process, and high quantum efficiency. However, the tunable emission, particularly a red emission, is still challenging to achieve. In the present study, a bright red emission (emission wavelength 620 nm under 365 nm UV excitation) of a manganese-doped BCNO (BCNO:Mn) phosphor synthesized by a solid state method is reported. Without Mn-doping, the BCNO phosphor exhibited a bright blue emission that can be ascribed to the closed-shell BO− and BO2− anions that act as luminescence center. Via Mn-doping, a red emission was exhibited that can be ascribed to the 4T1(4G) → 6A1(6S) transition from a new luminescence center of Mn2+ incorporated into the BCNO host lattice. The optimum red PL properties (λem: 611 nm, λex: 365 nm) were obtained with BCNO:Mn at a molar ratio of Mn/B at 0.71% mol/mol synthesized at 550 °C. We believe that the BCNO:Mn is a promising red-emitting phosphor for white light diodes.

Microwave-Assisted Solid State Synthesis of Red-Emitting BCNO Phosphor and its Characteristics

Red-emitting BCNO phosphor has been synthesized by a microwave-assisted solid state reaction using a low-cost boric acid, urea and polyethylene glycol (PEG-20k) as the starting materials. The effects of reaction parameters: temperature, carbon and nitrogen content on material composition and photoluminescence properties were investigated. Nearly multi-phase hexagonal boron nitride, boron oxide, boron carbide and carbon graphite was observed, indicating the BCNO were successfully synthesized. The photoluminescence spectra of the phosphor excited by a UV light (365 nm) showed a broad emission band at 460 - 620 nm.

Effect of Silica Nanoparticles on the Photoluminescence Properties of BCNO Phosphor

Effect of additional silica nanoparticles on the photoluminescence (PL) performance of boron carbon oxy‐nitride (BCNO) phosphor was investigated. As a precursor, boric acid and urea were used as boron and nitrogen sources, respectively. The carbon sources was polyethylene glycol (PEG) with average molecule weight 20000 g/mol.. Precursor solutions were prepared by mixing these raw materials in pure water, followed by stirring to achieve homogeneous solutions. In this precursor, silica nanoparticles were added at various mass ratio from 0 to 7 %wt in the solution. The precursors were then heated at 750 °C for 60 min in a ceramic crucible under atmospheric pressure. The photoluminescence (PL) spectrum that characterized by spectrophotometer showed a single, distinct, and broad emission band varied from blue to near red color, depend on the PEG, boric acid and urea ratio in the precursor. The addition of silica nanoparticles caused the increasing of PL intensity as well as the shifting of peak wavelength of P...

Introducing Organization Parameter for Self‐Organized Nanoparticles

We introduced a parameter to distinguish how well (the quality) of organization of nanoparticles in self‐organized samples. This parameter measures how far the deviation of real particle positions in the sample with respect to positions of particles forming a perfect lattice of the corresponding packing structure. The perfect lattice was developed by taking the lattice site as the average distance between contacting particles in the sample.

Synthesis and Morphology Properties of Mn-doped Zinc Aluminate (ZnAl2-xO4: xMn4+, x=1%) Using Co-Precipitation Methods with Microwave Thermal Assisted

ZnAl2O4: Mn4+ particle were synthesize using co-precipitation using NaOH and PVA as precipitating agent and surfactants, followed by microwave-assisted thermal treatment. The morphology properties and absorption spectral of particles were investigate using SEM and UV-Vis spectrometer. The results showed that the ZnAl2O4 particles has a spinel structure with various particle size. Absorption spectral exhibits that particle has a potential photo catalytic properties at visible light spectra, especially for the pollutant degradation.

A Facile Synthesis and Photoluminescence Properties of Boron Carbon Oxynitride (BCNO) Phosphor Materials for Security Ink Application

A facile synthesis of rare-earth free using boron carbon oxynitride (BCNO) phosphor material for security ink has been investigate. BCNO were synthesize by low temperature microwave heating methods, with H3BO3, citric acid and urea to be used as boron, carbon and nitrogen source, respectively. Then, the BCNO nanocrystals were disperse in water-polymer based solution until they became evenly spreading and turn into security ink without rare earth metals. The photoluminescence (PL) and UV-Visible spectroscopy were use to characterize the optical properties of BCNO and the security ink. The characterization results showed that BCNO and the security ink had similar PL properties (PL Peak and PL Peak Intensity). In addition, the UV-Vis spectra proved that the security ink had electronic properties such as being semiconductors based phosphor materials. The results indicate that BCNO phosphor material can be potentially be developed as rare-earth free security inks, and other applications such as optoelectronic, white LED, lighting, etc.

Synthesis of gadolinium carbonate-conjugated-poly(ethylene)glycol (Gd2(CO3)3@PEG) particles via a modified solvothermal method

PEGylated gadolinium carbonate ((Gd2(CO3)3)@PEG) powder was successfully synthesized by a modified solvothermal method. The synthesized products were characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). A systematic change in the chemical surface composition, crystallinity and size properties of the Gd2(CO3)3@PEG particles was observed by increasing the reaction time at 5 hours, 7 hours, and 8 hours. The corresponding XRD patterns showed that the Gd2(CO3)3 particles had hexagonal symmetry (JCPDS No. 37-0559) with a crystallite size of 3.5, 2.9, and 4.6 nm. FTIR spectra showed that the Gd2(CO3)3)@PEG particles were formed with the PEG as carbonyl and hydroxyl group attached to the surface. SEM analysis showed that the Gd2(CO3)3)@PEG particles had a flake-like morphology of homogeneous sized particles and agglomerates. EDS analysis confirmed the presence of constituent Gd2(CO3)3 ...

Effect of synthesis temperature on the morphology and electrical properties of solution-grown copper nanowires (CuNWs)

Copper nanowires (CuNWs) for different synthesis temperatures were prepared by solution-grown method. The surface morphology and electrical resistance of CuNWs were investigated. The surface morphology analysis describes the synthesis of long (> 20 µm), thin (< 60 nm), and mono-dispersed CuNWs. Thus, in the case of temperature treatment from 4 °C to 80 °C in water based solution, the CuNWs has diameter of about 71 nm, length up to 37 µm and electrical resistance (R) at 0.1 Ω. This study suggests that the as-prepared copper nanowires (CuNWs) with diameter and electrical resistance tunability might be utilized as flexible transparent conducting electrode.

Preliminary study on preparation of BCNO phosphor particles using citric acid as carbon source

A citric acid was used as a carbon source in the preparation of boron carbon oxy-nitride (BCNO) phosphor particles by a facile process. The preparation process was conducted at relatively low temperature 750 °C and at ambient pressure. The prepared BCNO phosphors showed a high photoluminescence (PL) performance at peak emission wavelength of 470 nm under excitation by a UV light 365 nm. The effects of carbon/boron and nitrogen/boron molar ratios on the PL properties were also investigated. The result showed that the emission spectra with a wavelength peak ranging from 444 nm to 496 nm can be obtained by varying carbon/boron ratios from 0.1 to 0.9. In addition, the observations showed that the BCNO phosphor material has two excitation peaks located at the 365 nm (UV) and 420 nm (blue). Based on these observations, we believe that the citric acid derived BCNO phosphor particles can be a promising inexpensive material for phosphor conversion-based white LED.

Fluorescent of C-dot composite thin films and its properties

In the present work, we report the preparation of a fluorescent carbon nanodots (C-dots) epoxy composite thin films on a glass substrate. C-dots were prepared directly by a simple hydrothermal method using citric acid as a carbon source. The C-dots solutions were mixed with a transparent epoxy resin to form C-dot epoxy composite. Furthermore, the composite precursor was deposited on the glass substrate using a spin coating method in order to fabricate C-dot epoxy composite thin film. The transmittance intensity of C-dot composite film reached up to 90% in the visible light spectra. Using Swanopoel method, the film thickness of fabricated C-dot composite film was determined at about 1.45 μm, a value lies in a typical range needed for a wide range application. Thus, the C-dot composite film is promising in broadening applications in various fields such as energy conversion, optoelectronics, and display technology.