Fluorescence properties of full-color-emitting BCNO phosphors synthesized under different oxygen pressure

Abstract

The colorful BCNO phosphors comprised of boron, carbon, nitrogen, and oxygen atoms have been novelty synthesized by varying the environmental oxygen pressure without changing the compositions of the raw materials such as boric, urea, and poly-ethylene glycol. X-ray diffraction (XRD), fourier-transformed infrared (FTIR), and photoluminescence (PL) spectra were employed to characterize the effect of environmental oxygen pressure on the structure and PL properties of the synthesized phosphors. The results of their PL properties indicates that the emission color of these BCNO phosphors has been easily tailored for a large-range from violet to near-red regions through variations of the environmental oxygen pressure as prepared under the excitation of 365 nm. This provides a new approach to tailor the emitting colors.Since phosphors materials are indispensable for our cultural life, excellent phosphors have been vigorously developed so far. Usually, common phosphor materials are composed by host materials and doped rare earth ions. However, the used luminescent centers in these phosphors are rare-earth elements that are typically expensive. Thus, the development of inexpensive phosphor materials is exciting from the viewpoint of not only cost of fabrication, but also of rare earth resource conservation. Up to now, much attention has been paid to this issue, for instance, developing phosphors consisting of transition-metal ions 1,2 and defect-related luminescence materials. 3 Chemically stable and highly emissive phosphor materials are always demanded for various applications such as display and lighting. Thus, oxynitride and nitride compounds as host lattices for phosphors arouse a fast-growing interest due to their excellent properties, such as non-toxicity, outstanding thermal and chemical stability, broad available range of excitation and emission wavelengths, and high luminescence efficiency upon activation using rare-earth ions. 4 However, the production of these materials generally requires high temperatures and pressures which increases the cost of production.Based on these reasons, the development of the materials with low fabrication cost is desirable for phosphors. Recently, an oxynitride phosphor BCNO without rare earth ions is developed by a one-step liquid process at low temperature (below 900 ○ C). 5 Due to the easy production and inexpensive raw materials in the synthetic process, it is a potential phosphor for applications in the fields of lighting, and optoelectronic nanodevices etc. Subsequently, much attention has been drawn to BCNO and many interesting results have been obtained. One of the important things is to obtain multicolors in the BCNO composition due to the prominent advantage of low cost. Usually, there are many ways to control the emitting color of a certain phosphor, for instance, valence state-controlled means, 6 energy transfer among activators, 7 and changing the crystal field or the bond covalence of Eu 2þ , Ce 3þ , Mn 2þ doped phosphors. 8 Different from the situation mentioned abov...

Fibrous Aerogel-Templated Nanostructured Boron Carbon Oxynitride Networks for Preferential Adsorptive Separation of Cationic Dyes

“… The XRD features of melamine and boric acid (Figure b,d) are entirely vanished, indicating the thermochemical conversion of melamine and boric acid into BCNO. The XRD pattern revealed the presence of h -BN phase doped with B 2 O 3 and graphitic carbon as a constituent of nanostructured BCNO. ,, …”

“…A broad spectral band in a range of 1150–950 cm –1 is attributed to overlapped features of N–B–O and B–C stretches. These vibrational features confirmed the preparation of BCNO enriched with B-–N, CC, CN, B–C, N-B–O, and B–O structural linkages and functionalities. , …”

“…These vibrational features confirmed the preparation of BCNO enriched with B-−N, C�C, C�N, B− C, N-B−O, and B−O structural linkages and functionalities. 47,48 Figure 2b−d illustrates the XRD patterns of BCNO and its precursors (melamine and boric acid). The diffraction peaks at 2θ of 25.4, 41.8, 45.4, and 52.7°(Figure 2c) signified the graphitic carbon network in BCNO and generated by thermochemical processing (1050 °C) of cellulosic fibers of cotton as a carbon source.…”

“…The XRD pattern revealed the presence of h-BN phase doped with B 2 O 3 and graphitic carbon as a constituent of nanostructured BCNO. 47,48,53 Electron micrographs are collected for probing the morphological features of CCT and BCNO. The CCT comprises twisted carbon fibers intertwined with each other (Figure 2e).…”