http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Singh, Vijay,Shinde, K.N.,Pathak, M.S.,Singh, N.,Dubey, Vikas,Singh, Pramod K.,Jirimali, H.D. Elsevier 2018 OPTIK -STUTTGART- Vol.164 No.-
<P><B>Abstract</B></P> <P>A series of Tb<SUP>3+</SUP>-doped CaLaAl<SUB>3</SUB>O<SUB>7</SUB> phosphors were successfully synthesized via a sol-gel method. The formation of the synthesized phosphors was confirmed using X-ray powder diffraction (XRPD) studies. A scanning electron microscope (SEM) was used to characterize the surface morphology and to investigate the photoluminescence behaviors in detail. Under the excitation of 235 nm, the emission spectrum consists of the characteristic Tb<SUP>3+</SUP> transitions that mainly peak at 543 nm and correspond to the <SUP>5</SUP>D<SUB>4</SUB> → <SUP>7</SUP>F<SUB>5</SUB> transition. The intensity was greatly improved due to the Tb<SUP>3+</SUP> concentration in the present phosphors. The optimum Tb<SUP>3+</SUP>-doping concentration was determined to be 0.05 mol. The chromaticity coordinates of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> were fixed to make it tunable for the blue-to-green region. The typical photographs of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> under a 254-nm UV light revealed an intense-green powder. The results showed that this kind of phosphor is potentially applicable in terms of UV-excited white LEDs.</P>
Singh, Vijay,Sivaramaiah, G.,Singh, N.,Rao, J. L.,Dubey, Vikas,Singh, Pramod K. Springer-Verlag 2018 Journal of materials science. Materials in electro Vol.29 No.8
<P>Fe-doped CaAl12O19 was prepared via a simple combustion route. The formation of the as-prepared and post-heated combustion products was confirmed using an XRD analysis. The EPR spectrum of this sample exhibited a number of resonance signals. The paramagnetic centers have been quantified at different g factors in the range of 19.3-1.14. These resonance signals are attributed to pairs of Fe3+ ions. The resonance signal at a g value of similar to 4.2 is attributed to the axial-symmetry tetrahedral site. The resonance signal at a g value of similar to 2.0 is attributed to the presence of Fe3+ ions in an axial-symmetry octahedral site. The EPR parameters of the post-heated CaAl12O19:Fe3+ sample at room temperature and 110 K were calculated and compared.</P>
Singh, Vijay,Pathak, M.S.,Singh, N.,Dubey, Vikas,Singh, Pramod K. Elsevier 2018 Optik Vol.152 No.-
<P><B>Abstract</B></P> <P>LiAl<SUB>5</SUB>O<SUB>8</SUB> doped with varying concentrations of Ce<SUP>3+</SUP> were synthesized by a combustion route. Powder X-ray diffraction and scanning electron microscopy techniques were used to characterize the as-prepared and annealed phosphors. The luminescence intensity decreased after annealing the samples at 800°C for 2h in air. These results indicate the possibility of fabrication of high quality Ce<SUP>3+</SUP> doped LiAl<SUB>5</SUB>O<SUB>8</SUB> phosphor even at furnace temperature 500°C via a simple process.</P>
PL and ESR of Gd3+ in LaMgAl11O19 phosphors
Singh, Vijay,Singh, N.,Pathak, M. S.,Watanabe, S.,Gundu Rao, T. K.,Singh, Pramod K.,Kwon, Young-Wan Springer-Verlag 2018 Journal of materials science Materials in electron Vol.29 No.6
<P>LaMgAl11O19 doped with different concentrations of gadolinium phosphors were synthesized by combustion and characterized using X-Ray diffraction to identify the crystalline phase. Photoluminescence studies on the sample showed emission peaks at 313 and 306 nm with lambda(exi) = 273 nm corresponding to the P-6 (J) -> S-8(7/2) transitions of Gd3+ ions. In phosphors with low dopant concentrations, dominant electron spin resonance lines are observed with g (eff) similar to 1.96, 1.98, 4.2, and 6.0. With increasing concentrations, the spectrum appears to be U-shaped, and main lines are seen at g (eff) similar to 1.98, 2.04, 2.8, 4.1 and 6.2. Distortions in the immediate environment of Gd3+ ions lead to relatively strong crystal fields and the appearance of lines in the low field region of the spectrum.</P>
Singh, Vijay,Singh, N.,Pathak, M.S.,Singh, Pramod K.,Natarajan, V. Elsevier 2018 Optik Vol.171 No.-
<P><B>Abstract</B></P> <P>Tb<SUP>3+</SUP>-doped Ca<SUB>2</SUB>La<SUB>8</SUB>(SiO<SUB>4</SUB>)<SUB>6</SUB>O<SUB>2</SUB> phosphors with different Tb<SUP>3+</SUP> content powders were successfully synthesized using the sol-gel process for this paper. A series of green-emitting Tb<SUP>3+</SUP>-doped Ca<SUB>2</SUB>La<SUB>8</SUB>(SiO<SUB>4</SUB>)<SUB>6</SUB>O<SUB>2</SUB> phosphors was well characterized using the XRD and PL techniques. The emission measurements upon a UV-light excitation of 232 nm showed the Tb<SUP>3+</SUP>-emission characteristics. The emission and excitation spectra were recorded as the Tb<SUP>3+</SUP> concentration was varied. It became evident that the addition of the Tb<SUP>3+</SUP> increased the PL intensity, and the reasons for this behavior are discussed.</P>
Singh, Vijay,Seshadri, M.,Singh, N.,Pathak, M.S.,Kumaran, R. Senthil,Choi, Yong-Keun,Singh, Pramod K.,Dhoble, S.J.,Srivastava, Anoop K. Elsevier 2016 Journal of luminescence Vol.176 No.-
<P><B>Abstract</B></P> <P>Combustion derived In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>, co-doped with Yb<SUP>3+</SUP>phosphor powders have been prepared. Powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy methods are used to characterize the prepared phosphor powders. The intensity parameters (<I>Ω<SUB>λ</SUB> </I>, <I>λ</I>=2, 4 and 6), radiative transition probabilities (<I>A<SUB>R</SUB> </I>), radiative lifetime (<I>τ<SUB>R</SUB> </I>) and branching ratios (<I>β</I>) of certain emission transition of Er<SUP>3+</SUP>ions for In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>and In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>phosphors have been estimated in the framework of the model given by Judd–Ofelt. Upon excitation at 978nm, upconversion luminescence properties of Er<SUP>3+</SUP>and Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>doped In<SUB>2</SUB>O<SUB>3</SUB> phosphors are investigated. The results obtained from optical study confirm the existence of an effective Yb<SUP>3+</SUP>to Er<SUP>3+</SUP>energy transfer process and it also predict possible mechanisms to populate the <SUP>4</SUP>S<SUB>3/2</SUB> and <SUP>4</SUP>F<SUB>9/2</SUB> levels. The possible upconversion mechanisms are discussed for Er<SUP>3+</SUP>and Yb<SUP>3+</SUP>ions with energy level diagram.</P>
Singh, Vijay,Singh, N.,Dubey, Vikas,Singh, Pramod K.,Shinde, K.N.,Ravi Kanth Kumar, V.V. Elsevier 2018 OPTIK -STUTTGART- Vol.158 No.-
<P><B>Abstract</B></P> <P>Ce<SUP>3+</SUP>-doped CaAl<SUB>12</SUB>O<SUB>19</SUB> phosphors with different Ce<SUP>3+</SUP> contents, as well as those with Mg<SUP>2+</SUP> codoped powders, were successfully synthesized using a rapid combustion method (<5 min) for this paper. The powders were well characterized by the X-ray diffraction (XRD) and photoluminescence (PL) techniques. The emission measurements upon a UV-light excitation (262 nm) showed the emission characteristics of the Ce<SUP>3+</SUP> ion that are due to the 5d–4 f transitions. The emission and excitation spectra were recorded as the Ce<SUP>3+</SUP> concentration was kept constant and the Mg<SUP>2+</SUP> concentration was varied. It became evident that the addition of the Mg<SUP>2+</SUP> along with the Ce<SUP>3+</SUP> resulted in increases of the PL intensity, and the reasons for this behavior are discussed.</P>
UV emission from Gd<sup>3+</sup> ions in LaAl<sub>11</sub>O<sub>18</sub> phosphors
Singh, Vijay,Singh, N.,Pathak, M.S.,Watanabe, S.,Gundu Rao, T.K.,Singh, Pramod K.,Dubey, Vikas Elsevier 2018 Optik Vol.157 No.-
<P><B>Abstract</B></P> <P>Phosphors with the composition La<SUB>1-x</SUB>Gd<SUB>x</SUB>Al<SUB>11</SUB>O<SUB>18</SUB> (x = 0.01–0.10) were synthesized by combustion at a furnace temperature of 500 °C. The formation of the as-prepared combustion products was confirmed by X-ray diffraction analysis. On excitation with 273 nm, an emission band for the Gd<SUP>3+</SUP> ion was observed at 314 nm. This band progressively enhanced with increasing Gd<SUP>3+</SUP> concentration. The phosphor with low concentrations of Gd<SUP>3+</SUP> ions exhibits prominent ESR lines with <I>g</I> <SUB>eff</SUB> ∼ 1.9, 2.0, 4.7, and 5.9. With high dopant concentrations, the spectrum shows features similar to those of a U-spectrum with dominant lines with <I>g</I> <SUB>eff</SUB> ∼ 2.0, 2.9, 4.6, and 6.1. Low field lines arise from distortions in the immediate environment of the Gd<SUP>3+</SUP> ion.</P>