Boron Carbon Oxynitride Phosphor Research Articles

Preparation of boron carbon oxynitride phosphor films with compositional and spectral tunability by chemical vapor deposition

Boron carbon oxynitride (BCNO) phosphor films exhibiting tunable chemical compositions and photoluminescence (PL) spectra were grown by chemical vapor deposition utilizing a laser using an alkylamido precursor with an oxidation gas. BCNO films exhibiting a dense, uniform microstructure and a turbostratic boron nitride (BN) structure was grown on a silicon substrate at 1323 K. Chemical bonding states investigated by X-ray photoelectron spectroscopy and X-ray absorption near edge structure of the BCNO films were like the hexagonal BN powder counterparts. The typical chemical compositions of BCNO phosphor films were B0.46−0.47C0.12−0.14N0.30−0.34O0.07−0.11, which was varied by regulating flow rates of the oxidation gas. The PL spectra generated under excitation at 360 nm exhibited multiple emission bands at 386, 405, 430, 473, 534, and 570 nm. BCNO films grown using higher C and O concentrations exhibited intensified PL peaks at 534 and 570 nm.

Facile synthesis and luminescence properties of tubular BCNO phosphor with orange emission assisted by bamboo fiber

In this work, tubular boron carbon oxynitride (BCNO) phosphors with orange-emitting are synthesized by bamboo fiber assistance. The effects of different sintering temperatures on the structure, morphology, and photoluminescence (PL) performance of BCNO phosphors were investigated. The results revealed that with the increase of sintering temperature, compared with the BCNO synthesized without the template, the synthesized BCNO phosphor with bamboo fiber as template gradually becomes a hollow tubular structure. Meanwhile, when the sintering temperature is 700 ℃, the BCNO phosphor shows bright orange emission at 315 nm excitation wavelength, and the quantum yield (QY) is up to 75%. Moreover, the prepared BCNO phosphor has a sensitive and selective quenching effect on Fe3+ ion under 365 nm portable ultraviolet lamp irradiation. By using the obtained BCNO phosphor as a fluorescence labeling marker, the fingerprint recognition on the object surfaces also could be realized.

Study of the effect of urea concentration on optical properties of Boron Carbon Oxynitride (BCNO) nanophosphor

Effect of urea concentration on optical properties of BCNO phosphor materials has been systematically investigated. Greenish-yellow luminescent BCNO phosphor materials were successfully synthesized by low-temperature, eco-friendly and non-toxic, green synthesis method. In this process, Boric acid (H3BO3 - 2 mol), Urea (NH2CONH2 - 0.25 mol–2 mol) and Lemon Aqueous extract (LAE - 20v/v%) were used as precursors. PXRD ascertains the crystallinity of prepared BCNO phosphor materials which reduces with increasing concentration of urea. The SEM and AFM images show the flakes type structure of prepared BCNO phosphor materials. Quantum yield increased up to 61 % for 0.5 mol% of urea and further decreased for higher concentration of urea. The Photoluminescence emission peak undergoes redshift on increasing the urea concentration up to 1.5 mol% and then saturates at higher concentration. PL emission in Greenish-Yellow region of as-prepared BCNO nanophosphor offers its potential application in WLED.

Preparation of boron carbon oxynitride phosphor film via laser chemical vapor deposition and annealing

The present study demonstrates the synthesis of a boron carbon oxynitride (BCNO) phosphor film by laser annealing treatment of a boron carbonitride (BCN) film via laser chemical vapor deposition (CVD) using a single precursor source. A dense and uniform BCN film (B0.38C0.37N0.25) was prepared on a fused quartz substrate at a high deposition rate of 18.4 μm h−1 via laser CVD at a deposition temperature of 1373 K using only tetrakis(dimethylamino) diboron with argon (Ar) as a carrier gas. The surface of the BCN film was subsequently annealed in air at 1223 K by laser irradiation for 300 s to obtain a BCNO thin film. A disordered boron nitride (BN) layered structure, turbostratic BN, with a one-dimensional orientation was formed in the BCNO thin film. Upon excitation at 375 nm, the BCNO thin film exhibited photoluminescence with a broad emission band at 580 nm. The combination of CVD using a less-hazardous precursor and short-time annealing using a high-power laser enabled the preparation of a thin BCNO phosphor film.

Melamine sponge-assisted synthesis of porous BCNO phosphor with yellow-green luminescence for Cr6+ detection

Boron carbon oxynitride (BCNO) was successfully prepared via the template of the melamine sponge. The resultant BCNO was characterized by infrared spectroscopy, fluorescence spectrophotometer, scanning electron microscope as well as quantum yield (QY). The results revealed that BCNO exhibit yellow-green photoluminescence under UV illumination with QY of 86%. For BCNO phosphor, the fluorescence is disappeared in the water, which limits its application in aqueous media. BCNO/polyvinyl alcohol (PVA) composite films were synthesized from BCNO phosphors and PVA hydrogels by simple mixing and coating. BCNO/PVA composite film can be visually detected Cr6+ at a concentration of about 103 μM when using a portable UV lamp. This portable fluorescent composite film sensor has potential applications in Cr6+ sensing.

Rapid synthesis and characterization of long afterglow BCNO phosphors by self-propagating combustion method

In this paper, non-rare-earth boron carbon oxynitride (BCNO) long afterglow phosphors were prepared by a rapid self-propagating combustion method. The precursor was obtained using boric acid, melamine and glycine as raw materials and then the BCNO phosphors with optimum luminescence properties were successfully synthesized after calcination of the precursor at 625 °C for 2 h in air atmosphere. The product and its luminescence properties were characterized with X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), excitation and emission spectra by fluorescence spectrometer. With the contents of increasing glycine, the luminescence emission peaks of as-prepared BCNO phosphors appear distinctly redshift, which is closely induced by the presence of different types of defects including the paramagnetic centre of nitrogen vacancies (VN), carbon and oxygen related impurity. In addition, the blue-purple emitting phosphors still remain long-lasting luminescence after stopping irradiation by UV light for 10 min. The developed BCNO phosphors have great practical applications in display, illumination, solar cell and biomedical fields.

Optical studies of MWCNT doped boron carbon oxynitride (BCNO) nano composite phosphor material

The BCNO (boron carbon oxynitride) phosphors have attracted much attention due to their excellent properties like non-toxicity, tunable emission spectra and easy synthesis processes. The present work investigates structural and luminescence properties of BCNO/MWCNTs (Boron Carbon Oxy-Nitride/Multi-Walled Carbon Nanotubes) nanocomposite phosphor materials, synthesized at 750 °C using combustion method. Boric acid (H3BO3), Citric Acid (C6H8O7) and Urea (NH2CONH2) were used as boron, carbon and nitrogen source in 1:1:2 M ratios. The concentration of MWCNT in BCNO phosphor was varied as 1, 3, 5, 7 wt%. XRD results show cubic B2O3, hexagonal carbon phase and h-BN structure in as-prepared phosphor nanocomposite. SEM images reveal controlled growth, uniform morphology and distribution in phosphor material with the increase in wt% concentration of MWCNT. Increase in wt% concentration of MWCNT increases crystallinity but reduces band gap in BCNO phosphor material. Better CIE color coordinates (x = 0.25, y = 0.25) are obtained for as-prepared nanocomposite which makes it an exceptional choice for chip-on board (COB) based WLEDs.

Effects of silver nanoparticles on enhancement of luminescence properties for BCNO phosphors with red emission

Boron carbon oxynitride (BCNO) phosphors with red emission were synthesized with solid phase method, and Ag nanoparticles were successfully used to improve the luminescence properties and quantum yields of BCNO phosphors. The spherical Ag nanoparticles with 10–30 nm were distributed evenly on the surface of BCNO phosphors with hexagonal structure. The silver (Ag) nanoparticles did not change the types of chemical bonding status of BCNO while affecting the intensity of some chemical bonds. The Ag nanoparticles can increase the excitation and emission intensity of BCNO phosphors, and the quantum yields of red emission can be improved about 8.4 times. The luminescence enhancement of BCNO phosphors was owing to the localized surface plasmon resonance of Ag nanoparticles and electron transition process between Ag and BCNO phosphors. The effects of Ag nanoparticles on band structure and electron transition process for BCNO phosphors were clarified via theoretical calculation and experimental results.

Mechanistic insights into tunable luminescence and persistent luminescence of the full-color-emitting BCNO phosphors

Boron carbon oxynitride (BCNO) phosphors can exhibit remarkable tunable emission colors and greenish persistent luminescence without the assistant of rare-earth ion dopants. However, the photoluminescent and persistent luminescence (PL) mechanisms of BCNO are still not fully understood. In this work, we attempt to reveal distinct photoluminescent and PL mechanism of BCNO based on the first-principles computation. Our results show that the tunable emission of BCNO stems from the carbon quantum dots (CQDs) embedded in the host BN lattice rather than originally expected from isolated carbon impurity. The embedded CQDs can emit light with size-dependent wavelength (color). Furthermore, oxygen ions chemisorbed at the edge of BCNO can passivate the dangling bonds, and thereby enhance BCNO's quantum efficiency. The PL mechanism can thus be attributed to the defect levels within the band gap, induced by CQDs. This mechanism is distinctly different from the conventional PL mechanism for the rare-earth-metal doped aluminate phosphors [Chem. Mater.2015, 27, 2195–2202]. The obtained new insights into the luminescent and PL mechanisms of BCNO will not only benefit engineering novel optical materials with improved PL properties, but also promote future R&D efforts in exploiting broader application opportunities for the BCNO family phosphors.

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.

Red photoluminescence BCNO synthesized from graphene oxide nanosheets

In this paper, we demonstrate the conversion of graphene oxide (GO) into boron carbon oxynitride (BCNO) hybrid nanosheets via a reaction with boric acid and urea, during which the boron and nitrogen atoms are incorporated into graphene nanosheets. The experimental results reveal that GO is important for the photoluminescence (PL) BCNO phosphor particles. More importantly, in this system, the prepared BCNO phosphors can be used to prepare the materials needed for red light emitting diodes (LEDs).

Photoluminescence optimization of BCNO phosphors synthesized using citric acid as a carbon source

Citric acid was used as carbon source for the optimization of the photoluminescence (PL) performance of boron carbon oxynitride (BCNO) phosphor. Citric acid was chosen as an alternative carbon source because of its simple molecular structure, low decomposition temperature, relative inexpensiveness, and environmental friendliness. The prepared sample exhibited a single, homogeneous, and broad photoluminescence emission band whose peak varied from near-UV (400nm) to yellow-visible (500nm) upon excitation at 365nm. The effects of varying the synthesis temperature, molar ratio of the carbon/boron and nitrogen/boron sources, and addition of SiO2 nanoparticles on the PL properties were also studied. The optimized BCNO phosphors may find potential use in white LED applications.

Spectral properties of BCNO phosphor with wide range of excitation and emission

Boron carbon oxynitride (BCNO) phosphors with wide excitation and emission range (up to 630nm emission peak) were prepared at 675°C under atmospheric pressure. Boric acid, melamine and glycerol were used as boron, nitrogen and carbon sources, respectively. The BCNO phosphor had turbostratic structure (t-BCN) and particle size was in the range of 10–50μm. FTIR results indicated that the and O were involved in the structure of samples and bonded to B and N to form BCNO phosphors. Both the excitation and emission spectra shifted to long wavelength and the emission peak position can be tuned from 460nm to 630nm with increasing glycerol. Ultraviolet–visible absorption spectra suggested that optical band gap of BCNO phosphors decreased with increasing glycerol. The spectra properties were closely related to the carbon related defects levels.

Thermoluminescence study of gamma irradiated BCNO nanophosphor

Boron carbon oxynitride (BCNO) is a low Zeff (≈6.8), near tissue equivalent material. Nanocrystals of the BCNO:Dy and BCNO:Cu were synthesized by solid state reaction method using different concentrations of dopants. TL characteristics of the synthesized BCNO and BCNO:Dy material doped with 2500ppm concentration of Dy were studied and compared with each other. It is observed that the doping of BCNO with Cu or Dy leads to the quenching of its TL properties. BCNO exhibits a linear response from 1×102 to 2×103Gy whereas BCNO:Dy exhibits a linear response from 1×102 to 1×103Gy of gamma radiations. Fading and reproducibility of phosphors are also studied and it is found that the undoped BCNO shows better TL results than that of Dy doped BCNO phosphor. The main disadvantages of this material are its low thermal stability and high fading, so further studies are needed for this material before concluding it as the best dosimeter for gamma doses.

Novel rare-earth-free tunable-color-emitting BCNO phosphors

We present a facile synthesis of novel, rare-earth (RE)-ion-free boron carbon oxynitride (BCNO) phosphors. The preparation method, chemical composition, luminescent properties and emission mechanisms, as well as current trends in BCNO phosphors are reviewed. The novel BCNO phosphors were synthesized from inexpensive and environmentally friendly raw materials by a straightforward route using liquid precursors at low temperatures under atmospheric pressure. The newly developed BCNO phosphors demonstrated tunable color emission, high quantum efficiency, and long-duration afterglow. The color emission of these phosphors can be tuned across almost the entire visible light spectrum by varying the molar ratios of the raw materials.

Effect of the Carbon Source on the Luminescence Properties of Boron Carbon Oxynitride Phosphor Particles

The effect of the carbon source on the optimization of the photoluminescence (PL) performance of boron carbon oxynitride (BCNO) phosphor particles was systematically investigated. Ethylene glycol, tetraethylene glycol (TEG), and poly(ethylene glycol) of various Mw values were used as the organic sources. When TEG was used, the BCNO phosphors exhibited high PL performance under excitation at 365 nm with a quantum efficiency of up to 60%. The emission spectrum peak of the prepared BCNO particles was affected by the Mw of the carbon sources. An additional study investigated in detail the effects of the carbon/boron and nitrogen/boron molar ratios on PL properties. The emission spectra with a wavelength peak ranging from 380 nm (near UV) to 570 nm (near red) could be adjusted by varying the carbon/boron or nitrogen/boron ratios.