Papers by Dr. Manveer Singh
Journal of Atomic, Molecular, Condensed Matter and Nano Physics
International Journal of Health Sciences (IJHS), May 31, 2022
Individual poly(methyl methacrylate)/MWCNT doped with sulfuric acid were polymerized in situ to y... more Individual poly(methyl methacrylate)/MWCNT doped with sulfuric acid were polymerized in situ to yield individual nanotubes with increased electrical conductivity. In the presence of aliphatic alcohol vapors of various diameters, the Nanocomposites were measured as a function of time. These sensor responses are particularly rapid due to the huge surface to volume ratio, consistent diameter, and limited amount of active material employed in the design. Individual nanotube sensors demonstrate actual saturation when exposed to and removed from the detecting gas. In addition, a chemical sensing system was created employing a nanocomposite film in both air and vapor alcohol gas. When exposed to alcohol, the surface reaction was immediate, with virtually total current recovery 10237 after pumping out the alcohol, making it a reusable sensor with rectifying behaviour.
Journal of Atomic, Molecular, Condensed Matter and Nano Physics
Thulium (Tm 3+) ions doped Barium Bromide Fluoride (BaBrF) samples were synthesized successfully ... more Thulium (Tm 3+) ions doped Barium Bromide Fluoride (BaBrF) samples were synthesized successfully through the solid-state diffusion method. The crystal structure and phase purity of the synthesized sample were examined by Powder X-Ray Diffraction (PXRD) analysis. Dosimetric properties of γ-ray exposed samples of BaBrF:Tm 3+ investigated. To obtain the maximum Thermoluminescence (TL) sensitivity of the material, the dopant concentration level and annealing temperature were optimized. It is observed that the dopant concentration 2.0 mol% of Tm 3+ and the annealing at 673 K temperature the phosphor material exhibits maximum TL intensity. The γ-Ray dose-response, fading of the TL signal, and kinetic parameters of the TL glow curve were also investigated. TL sensitivity of the BaBrF:Tm 3+ phosphor compared to the commercially available CaSO 4 :Dy (TLD-900) dosimeter used for radiation measurement. On the basis of their promising dosimetric characteristics, it can become a good TL dosimeter for passive dosimetry of high energy γ-ray radiation.
Journal of Atomic, Molecular, Condensed Matter and Nano Physics
New NaLi 2 PO 4 , phosphor doped with 0.5 mole% Eu 3 + prepared by solid state method were used f... more New NaLi 2 PO 4 , phosphor doped with 0.5 mole% Eu 3 + prepared by solid state method were used for carbon dosimetry. XRD of the material matched with the data available in the literature (JCPDS file #80-2110) and confirmed formation of the material in its orthorhombic structure. The TL of the carbon beam irradiated sample recorded on Harshaw TLD-3500 reader. The samples are irradiated for different fluencies from the range of 5 × 10 9 to 1 × 10 13 ions cm −2. TL glow curve consist of single main TL peak around 457 K surrounded by kinks at 408, 504 and 542 K. TL glow curve of the carbon irradiated sample has same shape as that of gamma irradiated one. With increasing dose the intensity is increases. The phosphor is much more sensitive than the standard available standard phosphor. It is about 6.5 and 41.3 times more sensitive than the TLD-100 and TLD-700H. For these range of fluences phosphor show sub-linearity. Efficiency of the for phosphor for C 6+ with respect to gamma radiation is calculated and is around 0.50754 for the fluence of 5 × 10 09 ions cm −2 .
Journal of Atomic, Molecular, Condensed Matter and Nano Physics
Journal of Luminescence and Applications, 2016
Eu 3+ doped NaLi2PO4 sample synthesized via high temperature solid-state reaction exhibits the in... more Eu 3+ doped NaLi2PO4 sample synthesized via high temperature solid-state reaction exhibits the intense red emission under excitation to wavelength 318 nm light. In the photoluminescence (PL) emission spectra shown usual five emission peaks centered at around 580, 593, 618, 653, and 702 nm corresponding to the allowed transitions 5 D0→ 7 FJ (J = 0, 1, 2, 3, and 4) of Eu 3+ ion. The most prominent peaks were observed at 653 and 702 nm which increased the chromaticity quality followed dark red color with chromaticity coordinate (0.6298, 0.3589) and correlated color temperature (CCT) 1106 K. On exposing to γ-radiation, the red emission of Eu 3+ doped NaLi2PO4 phosphor diminished due to the reduction of Eu 3+ to Eu 2+ ions. The reduction of Eu 3+ → Eu 2+ was examined from the emission spectra of irradiated Eu 3+ doped NaLi2PO4 sample. Tuning the red emission of Eu 3+ doped NaLi2PO4 was observed and calculated the CIE (Commission Internationale de L'Eclairage) chromatic coordinates (chromatic coordinate (x, y), Correlated Color Temperature (CCT) and Duv etc.).
Radiation Measurements, 2015
Abstract Nanocrystalline samples of Mn-doped CaF2 were synthesized by chemical coprecipitation me... more Abstract Nanocrystalline samples of Mn-doped CaF2 were synthesized by chemical coprecipitation method. The impurity concentration was varied in the range of 0.5–4.0 mol%. The structure of the synthesized material was confirmed using powder XRD analysis. TEM images of the nanoparticles show their size occurring mostly in the range of 35–40 nm, with clusters of some impurity phases formed on annealing of the material at higher temperatures. Detailed studies on TL showed that the structures of glow curves depend on Mn concentrations and annealing temperatures. Optimization of the concentration and annealing temperature showed that the sample (doped with 3.0 mol% and annealed at 673 K) has almost a single dosimetric glow peak appearing at around 492 K. EPR and PL spectra were further studied to understand the reasons for changes in the glow curve structures. All detailed studies on TL, PL and EPR showed that the changes in glow curve structures are caused not only by the stress connected with the difference in ionic radii of host Ca2+ and the guest impurity Mn3+/Mn2+, but are also governed by other reasons, like diffusion of atmospheric oxygen and formation of impurity aggregates, such as, MnO2, Mn3O4, etc. This is true not only for nanocrystalline CaF2:Mn but could also be so for the bulk CaF2:Mn (TLD-400) and would thus help in understanding complex glow curve structure, high fading and the loss of reusability on annealing beyond 673 K.
Indian Journal of Physics, 2014
ABSTRACT Eu3+ doped NaLi2PO4 red luminescent phosphor has been synthesized by solid state reactio... more ABSTRACT Eu3+ doped NaLi2PO4 red luminescent phosphor has been synthesized by solid state reaction and its phase purity has been confirmed by X-ray diffraction analysis. Optical properties of the phosphor have been investigated and the effect of dopant (Eu3+) concentration (0.1–3.0 mol%) has been observed. Excitation spectra of the phosphor NaLi2PO4:Eu3+ show a very efficient absorbance band corresponding to the common allowed transition 7F 0 → 5L 6 occurring at 393 nm, while the luminescence spectra exhibit prominent emission peak centered at 702 nm (5D 0 → 7F 4) in pure red region. Color purity of this red phosphor has been calculated and found to be around 99.9 %, which is very close to that of commercial red phosphor Y2O3:Eu3+. Luminescence studies of the phosphor show excellent stability with respect to excitation energy. Chromatic investigations have also been performed using emission spectrum and some important chromatic parameters are calculated using CIE-1931 color calculator in order to find potential application of the phosphor.
Journal of Luminescence, 2015
ABSTRACT In the present paper optimized dosimetric characteristics of low-Z magnesium tetra-borat... more ABSTRACT In the present paper optimized dosimetric characteristics of low-Z magnesium tetra-borate MgB4O7:Mn,Tb using a thermoluminescence (TL) technique have been reported. The phosphor material was synthesized using a conventional high temperature solid-state diffusion reaction. The crystalline structure and phase purity of synthesized powder were confirmed by powder X-ray diffraction (XRD) analysis. The material in the microcrystalline form was found to be in orthorhombic form. The comparative dosimetric properties of the phosphor material have been extensively investigated for its applications in personal and medical dosimetry. It has been found that the codoped MgB4O7:Mn,Tb material, exposed to γ rays, shows better TL sensitivity and has an edge over the Mn and Tb doped samples as it is much more sensitive than the formers (550 and 40 times, respectively, more than the later ones). It has a simple glow curve structure (two well separated TL peaks centered at around 475 and 650 K). They are sufficiently above the room temperature (RT) to show low fading (~10% in a month after storing in dark at RT). However, the fading is much faster, if exposed to sunlight/room light/UV radiation. This has been a serious problem with many borate based phosphors. A detailed study on bleaching to UV–visible light of different wavelengths (energies) has been carried out and a new mechanism based on redox reactions is proposed. Low fading (~10% in a month) at room temperature on storing in dark, high TL sensitivity (3.5 times than that of TLD-100), tissue equivalence (Zeff≈8.23) and linear dose response up to wide range (0.1 Gy to ~5.0 kGy) of γ rays make it a suitable candidate for the radiation dosimetry and monitoring. However, it needs to be protected from sunlight/room light for fast fading.
Journal of Radioanalytical and Nuclear Chemistry, 2014
ABSTRACT Ce3+-doped NaLi2PO4 orthophosphate (with different impurity concentrations, i.e., 0.01-0... more ABSTRACT Ce3+-doped NaLi2PO4 orthophosphate (with different impurity concentrations, i.e., 0.01-0.3 mol%) was prepared by a solid state reaction method. Formation of the material was confirmed using powder X-ray diffraction analysis. TL intensity was found to be the highest for the material having impurity concentration 0.2 mol% after annealing it at around 600 K for 1 h and subsequently quenching to room temperature. A typical glow curve consists of three peaks at around 454, 493 and 570 K (dosimetry peak). Good sensitivity (similar to 8 times more than that of TLD-100), low fading (similar to 15 % in 2 months), low-Z material (Z (eff) a parts per thousand 10.8), very wide dose response (i.e., 0.1 Gy-1.0 kGy of gamma rays) make the material a 'good' thermoluminescent dosimeter (TLD) phosphor suitable for personnel, medical and environmental dosimetry of high-energy radiation using TL. It could also be used during cancer therapy and sterilization of food where high doses are needed to be monitored.
Radiation Measurements, 2013
ABSTRACT A new highly sensitive, low-Z (Zeff ≈ 10.8) TLD phosphor, Eu3+ doped NaLi2PO4, was succe... more ABSTRACT A new highly sensitive, low-Z (Zeff ≈ 10.8) TLD phosphor, Eu3+ doped NaLi2PO4, was successfully synthesized via solid state diffusion method. The formation of the single phase compound was confirmed by Powder X-Ray diffraction (PXRD) analysis. Variation of the doping level has shown that the impurity (Eu3+) concentration for maximum TL sensitivity is 0.5 mol%. Heat treatments given to achieve the high TL sensitivity of this phosphor also showed that it needs to be annealed at 973 K for 1 h. Incorporation of the impurity in the Eu+3 states was confirmed by the PL emission peaks. The TL glow curve consists of a prominent dosimetry peak at around 458 K besides small shoulders on both sides at around 400 and 500 K. The dose response of the phosphor was found to be sub-linear up to 10 Gy of the dose and later it becomes linear till it start saturating beyond 1 kGy. The TL sensitivity of the newly developed NaLi2PO4:Eu3+ phosphor to γ radiation from 137Cs (in the linear dose range) was compared to some standard commercially available phosphors, such as, TLD-100, TLD-400, TLD-700H and TLD-900. It was found to be much more sensitive than these phosphors except TLD-700H, which is ∼2 times more sensitive. Easy method of synthesis, simple glow curve structure, high sensitivity, low fading, wide range of doses and very good reusability make the phosphor a suitable candidate for the TL dosimetry.
Proceedings of the World …, 2009
Abstract Nano-crystalline Diamond like Carbon (DLC) film has been grown by Dense Plasma Focusing... more Abstract Nano-crystalline Diamond like Carbon (DLC) film has been grown by Dense Plasma Focusing Method (DPF) using pure graphite Plasma, on different substrate (glass/silica) at different substrate temperature. The films were grown at substrate temperature 1000C, 1500C & ...
RSC Adv., 2014
A new high sensitivity Na2LiPO4:Eu optically stimulated luminescence dosimeter (OSLD) material wa... more A new high sensitivity Na2LiPO4:Eu optically stimulated luminescence dosimeter (OSLD) material was prepared by a simple solid-state diffusion method.
Nano‐crystalline Diamond like Carbon (DLC) film has been grown by Dense Plasma Focusing Method (D... more Nano‐crystalline Diamond like Carbon (DLC) film has been grown by Dense Plasma Focusing Method (DPF) using pure graphite Plasma, on different substrate (glass∕silica) at different substrate temperature. The films were grown at substrate temperature 100° C, 150° C & 300° C by ...
Eu 3+ doped NaLi2PO4 sample synthesized via high temperature solid-state reaction exhibits the in... more Eu 3+ doped NaLi2PO4 sample synthesized via high temperature solid-state reaction exhibits the intense red emission under excitation to wavelength 318 nm light. In the photoluminescence (PL) emission spectra shown usual five emission peaks centered at around 580, 593, 618, 653, and 702 nm corresponding to the allowed transitions 5 D0→ 7 FJ (J = 0, 1, 2, 3, and 4) of Eu 3+ ion. The most prominent peaks were observed at 653 and 702 nm which increased the chromaticity quality followed dark red color with chromaticity coordinate (0.6298, 0.3589) and correlated color temperature (CCT) 1106 K. On exposing to γ-radiation, the red emission of Eu 3+ doped NaLi2PO4 phosphor diminished due to the reduction of Eu 3+ to Eu 2+ ions. The reduction of Eu 3+ → Eu 2+ was examined from the emission spectra of irradiated Eu 3+ doped NaLi2PO4 sample. Tuning the red emission of Eu 3+ doped NaLi2PO4 was observed and calculated the CIE (Commission Internationale de L'Eclairage) chromatic coordinates (chromatic coordinate (x, y), Correlated Color Temperature (CCT) and Duv etc.).
Nanocrystalline samples of Mn-doped CaF2 were synthesized by chemical coprecipitation method. The... more Nanocrystalline samples of Mn-doped CaF2 were synthesized by chemical coprecipitation method. The
impurity concentration was varied in the range of 0.5e4.0 mol%. The structure of the synthesized material
was confirmed using powder XRD analysis. TEM images of the nanoparticles show their size
occurring mostly in the range of 35e40 nm, with clusters of some impurity phases formed on annealing
of the material at higher temperatures. Detailed studies on TL showed that the structures of glow curves
depend on Mn concentrations and annealing temperatures. Optimization of the concentration and
annealing temperature showed that the sample (doped with 3.0 mol% and annealed at 673 K) has almost
a single dosimetric glow peak appearing at around 492 K. EPR and PL spectra were further studied to
understand the reasons for changes in the glow curve structures. All detailed studies on TL, PL and EPR
showed that the changes in glow curve structures are caused not only by the stress connected with the
difference in ionic radii of host Ca2þ and the guest impurity Mn3þ/Mn2þ, but are also governed by other
reasons, like diffusion of atmospheric oxygen and formation of impurity aggregates, such as, MnO2,
Mn3O4, etc. This is true not only for nanocrystalline CaF2:Mn but could also be so for the bulk CaF2:Mn
(TLD-400) and would thus help in understanding complex glow curve structure, high fading and the loss
of reusability on annealing beyond 673 K.
A new high sensitivity Na2LiPO4:Eu optically stimulated luminescence dosimeter (OSLD) material wa... more A new high sensitivity Na2LiPO4:Eu optically stimulated luminescence dosimeter (OSLD) material was
prepared by a simple solid-state diffusion method. The formation of the material was confirmed by
comparing the experimental data with that available in the literature (JCPDF # 80-2110). The dosimetric
properties of the phosphor material using a continuous wave-optically stimulated luminescence (CWOSL)
technique were studied. The material was studied for different concentrations of the impurity and
also for different heating treatments. The material doped with 1.0 mol% and annealed at 873 K was
found to be the most sensitive. The phosphor was found to have all the good dosimetric characteristics,
such as tissue equivalence (low-Z, Zeff 10.8), high sensitivity (3 times less than the commercially
available Al2O3:C, Landauer Inc., USA and BeO, Thermalox® 995, Materion Inc., USA), low fading (6.2%
in 40 days), wide range of dose response (0.1–1.0 kGy), excellent reusability, easy optical bleaching
(annealing) for its reuse, etc., which makes the material useful for dosimetry of high-energy radiations
using OSL. The advantages of our OSLD phosphor are the easily available and inexpensive ingredients
and a very simple method of preparation that makes it cost effective as compared to the commercially
available OSLD phosphors. Also, it is easy to handle, unlike the Thermalox® 995 (BeO) dosimeters which
are very toxic, and require a special method of preparation and handling.
Nano-crystalline Diamond like Carbon (DLC)
film has been grown by Dense Plasma Focusing Method (D... more Nano-crystalline Diamond like Carbon (DLC)
film has been grown by Dense Plasma Focusing Method (DPF)
using pure graphite Plasma, on different substrate (glass/silica)
at different substrate temperature. The films were grown at
substrate temperature 1000C, 1500C & 3000C by the high dense
plasma of energy 1.3 k Joule on glass and silica. Raman spectra
confirmed that sp3 content in grown in the films under various
conditions. The Raman spectra of these films show a broad
asymmetric peak which narrow with decreasing sp2 contents.
We believe that our data presented here may be used as
reference of DLC characterization.
Eu3? doped NaLi2PO4 red luminescent phosphor has been synthesized by solid state reaction and its... more Eu3? doped NaLi2PO4 red luminescent phosphor has been synthesized by solid state reaction and its phase
purity has been confirmed by X-ray diffraction analysis. Optical properties of the phosphor have been investigated and the
effect of dopant (Eu3?) concentration (0.1–3.0 mol%) has been observed. Excitation spectra of the phosphor NaLi2-
PO4:Eu3? show a very efficient absorbance band corresponding to the common allowed transition 7F0 ? 5L6 occurring at
393 nm, while the luminescence spectra exhibit prominent emission peak centered at 702 nm (5D0 ? 7F4) in pure red
region. Color purity of this red phosphor has been calculated and found to be around 99.9 %, which is very close to that of
commercial red phosphor Y2O3:Eu3?. Luminescence studies of the phosphor show excellent stability with respect to
excitation energy. Chromatic investigations have also been performed using emission spectrum and some important
chromatic parameters are calculated using CIE-1931 color calculator in order to find potential application of the phosphor.
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Papers by Dr. Manveer Singh
impurity concentration was varied in the range of 0.5e4.0 mol%. The structure of the synthesized material
was confirmed using powder XRD analysis. TEM images of the nanoparticles show their size
occurring mostly in the range of 35e40 nm, with clusters of some impurity phases formed on annealing
of the material at higher temperatures. Detailed studies on TL showed that the structures of glow curves
depend on Mn concentrations and annealing temperatures. Optimization of the concentration and
annealing temperature showed that the sample (doped with 3.0 mol% and annealed at 673 K) has almost
a single dosimetric glow peak appearing at around 492 K. EPR and PL spectra were further studied to
understand the reasons for changes in the glow curve structures. All detailed studies on TL, PL and EPR
showed that the changes in glow curve structures are caused not only by the stress connected with the
difference in ionic radii of host Ca2þ and the guest impurity Mn3þ/Mn2þ, but are also governed by other
reasons, like diffusion of atmospheric oxygen and formation of impurity aggregates, such as, MnO2,
Mn3O4, etc. This is true not only for nanocrystalline CaF2:Mn but could also be so for the bulk CaF2:Mn
(TLD-400) and would thus help in understanding complex glow curve structure, high fading and the loss
of reusability on annealing beyond 673 K.
prepared by a simple solid-state diffusion method. The formation of the material was confirmed by
comparing the experimental data with that available in the literature (JCPDF # 80-2110). The dosimetric
properties of the phosphor material using a continuous wave-optically stimulated luminescence (CWOSL)
technique were studied. The material was studied for different concentrations of the impurity and
also for different heating treatments. The material doped with 1.0 mol% and annealed at 873 K was
found to be the most sensitive. The phosphor was found to have all the good dosimetric characteristics,
such as tissue equivalence (low-Z, Zeff 10.8), high sensitivity (3 times less than the commercially
available Al2O3:C, Landauer Inc., USA and BeO, Thermalox® 995, Materion Inc., USA), low fading (6.2%
in 40 days), wide range of dose response (0.1–1.0 kGy), excellent reusability, easy optical bleaching
(annealing) for its reuse, etc., which makes the material useful for dosimetry of high-energy radiations
using OSL. The advantages of our OSLD phosphor are the easily available and inexpensive ingredients
and a very simple method of preparation that makes it cost effective as compared to the commercially
available OSLD phosphors. Also, it is easy to handle, unlike the Thermalox® 995 (BeO) dosimeters which
are very toxic, and require a special method of preparation and handling.
film has been grown by Dense Plasma Focusing Method (DPF)
using pure graphite Plasma, on different substrate (glass/silica)
at different substrate temperature. The films were grown at
substrate temperature 1000C, 1500C & 3000C by the high dense
plasma of energy 1.3 k Joule on glass and silica. Raman spectra
confirmed that sp3 content in grown in the films under various
conditions. The Raman spectra of these films show a broad
asymmetric peak which narrow with decreasing sp2 contents.
We believe that our data presented here may be used as
reference of DLC characterization.
purity has been confirmed by X-ray diffraction analysis. Optical properties of the phosphor have been investigated and the
effect of dopant (Eu3?) concentration (0.1–3.0 mol%) has been observed. Excitation spectra of the phosphor NaLi2-
PO4:Eu3? show a very efficient absorbance band corresponding to the common allowed transition 7F0 ? 5L6 occurring at
393 nm, while the luminescence spectra exhibit prominent emission peak centered at 702 nm (5D0 ? 7F4) in pure red
region. Color purity of this red phosphor has been calculated and found to be around 99.9 %, which is very close to that of
commercial red phosphor Y2O3:Eu3?. Luminescence studies of the phosphor show excellent stability with respect to
excitation energy. Chromatic investigations have also been performed using emission spectrum and some important
chromatic parameters are calculated using CIE-1931 color calculator in order to find potential application of the phosphor.
impurity concentration was varied in the range of 0.5e4.0 mol%. The structure of the synthesized material
was confirmed using powder XRD analysis. TEM images of the nanoparticles show their size
occurring mostly in the range of 35e40 nm, with clusters of some impurity phases formed on annealing
of the material at higher temperatures. Detailed studies on TL showed that the structures of glow curves
depend on Mn concentrations and annealing temperatures. Optimization of the concentration and
annealing temperature showed that the sample (doped with 3.0 mol% and annealed at 673 K) has almost
a single dosimetric glow peak appearing at around 492 K. EPR and PL spectra were further studied to
understand the reasons for changes in the glow curve structures. All detailed studies on TL, PL and EPR
showed that the changes in glow curve structures are caused not only by the stress connected with the
difference in ionic radii of host Ca2þ and the guest impurity Mn3þ/Mn2þ, but are also governed by other
reasons, like diffusion of atmospheric oxygen and formation of impurity aggregates, such as, MnO2,
Mn3O4, etc. This is true not only for nanocrystalline CaF2:Mn but could also be so for the bulk CaF2:Mn
(TLD-400) and would thus help in understanding complex glow curve structure, high fading and the loss
of reusability on annealing beyond 673 K.
prepared by a simple solid-state diffusion method. The formation of the material was confirmed by
comparing the experimental data with that available in the literature (JCPDF # 80-2110). The dosimetric
properties of the phosphor material using a continuous wave-optically stimulated luminescence (CWOSL)
technique were studied. The material was studied for different concentrations of the impurity and
also for different heating treatments. The material doped with 1.0 mol% and annealed at 873 K was
found to be the most sensitive. The phosphor was found to have all the good dosimetric characteristics,
such as tissue equivalence (low-Z, Zeff 10.8), high sensitivity (3 times less than the commercially
available Al2O3:C, Landauer Inc., USA and BeO, Thermalox® 995, Materion Inc., USA), low fading (6.2%
in 40 days), wide range of dose response (0.1–1.0 kGy), excellent reusability, easy optical bleaching
(annealing) for its reuse, etc., which makes the material useful for dosimetry of high-energy radiations
using OSL. The advantages of our OSLD phosphor are the easily available and inexpensive ingredients
and a very simple method of preparation that makes it cost effective as compared to the commercially
available OSLD phosphors. Also, it is easy to handle, unlike the Thermalox® 995 (BeO) dosimeters which
are very toxic, and require a special method of preparation and handling.
film has been grown by Dense Plasma Focusing Method (DPF)
using pure graphite Plasma, on different substrate (glass/silica)
at different substrate temperature. The films were grown at
substrate temperature 1000C, 1500C & 3000C by the high dense
plasma of energy 1.3 k Joule on glass and silica. Raman spectra
confirmed that sp3 content in grown in the films under various
conditions. The Raman spectra of these films show a broad
asymmetric peak which narrow with decreasing sp2 contents.
We believe that our data presented here may be used as
reference of DLC characterization.
purity has been confirmed by X-ray diffraction analysis. Optical properties of the phosphor have been investigated and the
effect of dopant (Eu3?) concentration (0.1–3.0 mol%) has been observed. Excitation spectra of the phosphor NaLi2-
PO4:Eu3? show a very efficient absorbance band corresponding to the common allowed transition 7F0 ? 5L6 occurring at
393 nm, while the luminescence spectra exhibit prominent emission peak centered at 702 nm (5D0 ? 7F4) in pure red
region. Color purity of this red phosphor has been calculated and found to be around 99.9 %, which is very close to that of
commercial red phosphor Y2O3:Eu3?. Luminescence studies of the phosphor show excellent stability with respect to
excitation energy. Chromatic investigations have also been performed using emission spectrum and some important
chromatic parameters are calculated using CIE-1931 color calculator in order to find potential application of the phosphor.