Pecharapa, Wisanu

Preferred name

Pecharapa, Wisanu

Alternative Name

PECHARAPA, Wisanu

Pecharapa, W.

Main Affiliation

Integrated Innovative Technology

wisanu.pe@kmitl.ac.th

Now showing 1 - 10 of 20

Some of the metrics are blocked by your
consent settings
Spectroscopic investigation and local structure of Eu3+ ions in lead phosphate glasses for optical device applications
(2024-04-01)
Basavapoornima, Ch
;
Masthanaiah, E.
;
Vijaya, N.
;
Depuru, Shobha Rani
;
Kaewkhao, J.
Phosphate-based glasses are promising materials which are being employed for broad range of applications whereas Eu3+ is an efficient activator due to its predominant 5D<inf>0</inf> →7F<inf>2</inf> emission (red region). In this direction, an attempt has been made to investigate the effect of Eu3+ ions doped lead phosphate glasses (PPbKANEu: P<inf>2</inf>O<inf>5</inf>+PbO+K<inf>2</inf>O+Al<inf>2</inf>O<inf>3</inf>+Na<inf>2</inf>O+Eu<inf>2</inf>O<inf>3</inf>) to explore possible photonic device applications. Optical absorption, excitation, photoluminescence and decay rates are used to characterize the PPbKANEu glasses. The photoluminescence spectrum of Eu3+:PPbKAN glasses exhibit emission channels from the first excited (5D<inf>0</inf>) to the ground (7F<inf>J</inf> (J =0–4)) multiplets. To determine the local site symmetry of surrounding Eu3+ ions, the relative fluorescence intensity ratio of 5D<inf>0</inf>→7F<inf>1</inf> versus 5D<inf>0</inf>→7F<inf>2</inf> emission channels has been analyzed. The emission spectrum of PPbKANEu glasses exhibits a comprehensive lifting of degeneracy of 5D<inf>0</inf>→7F<inf>2</inf> and 5D<inf>0</inf>→7F<inf>1</inf> emission channels. By considering C<inf>2v</inf> symmetry for Eu3+ ions, the second (B<inf>0</inf>2= −406 and B<inf>2</inf>2=−158) and fourth (B<inf>0</inf>4=980, B<inf>2</inf>4=297 and B<inf>4</inf>4=926 cm–1) rank crystal–field (CF) characteristics were estimated along with CF strength factor (S= 402 cm–1). The lifetime of 5D<inf>0</inf> state is estimated to be 2.09, 2.23, 2.21 and 2.21 ms for 0.1, 0.5, 1.0 and 2.0 mol% of Eu3+ ions, respectively. The analysis of the decay times reveals that the lifetime of 5D<inf>0</inf> state is less affected by the concentration of the Eu3+ ion. The results are compared and discussed with reported values and confirm the potentiality of the PPbKANEu glasses for optical device applications in visible regions.
Some of the metrics are blocked by your
consent settings
Optimization of Pr3+-doped glasses for photonic applications: an overview and challenges in Judd–Ofelt analysis
(2026-07-17)
Kesavulu, C. R.
;
Soumya, S.
;
Saikia, Darshana
;
Jayasankar, Deviprasad Chalicheemalapalli
;
Pecharapa, Wisanu
Characteristics (optical, luminescence, up-conversion, etc.) of triply ionized Praseodymium (Pr3+) ions doped glasses, glass-ceramics, phosphors and crystals have been widely studied for the development of photonic devices. Most of these characteristics are mainly based on Judd–Ofelt (JO) theory to interpret transition intensities and in turn to simulate radiative properties of Pr3+ ions based optical materials. However, JO analysis provides inconsistent results for Pr3+:glasses. Further, besides no review is available focusing on uneven findings of Pr3+:glasses. Therefore, a comprehensive data on Pr3+:glasses have been collected (490 Pr3+:glasses) and compared, besides labeling glass compositions systematically. The properties that are reviewed include, Nephelauxetic effect, optical energy gap, thermal, JO parameters, radiative properties, etc. It has been noticed that the systematic study either in preparation or optimization of characteristic properties are very much missing. Moreover, large number of data sets of literature are presented at one place which is very much useful for predictive modeling approaches. Also, the primary focus of the present review is not to provide a comprehensive summary of all studies conducted so far or to discuss new findings, but rather to highlight the challenges associated with JO parameters for Pr3+ ions that influence the development of optical materials, components, and applications.
Some of the metrics are blocked by your
consent settings
Effect of Ultrasonic Irradiation Time on Physical Properties and Photocatalytic Performance of BiVO4 Nanoparticles Prepared via Sonochemical Process
(2021-01-01)
Kansaard, Thanaphon
;
Bangbai, Chatpong
;
Jayasankar, C. K.
;
Pecharapa, Wisanu
Currently, photocatalyst materials have gained considerable attraction because of very rich economic performance of decomposition of highly toxic organic compound to lower toxic composition. The effort of this work was paid to study the effect of sonochemical ultrasonic irradiation time on the relevant properties of visible-light-driven bismuth vanadate (BiVO<inf>4</inf>) photocatalyst without any further thermal treatment process. The chemical bonding of BiVO<inf>4</inf> nanopowder was investigated by Fourier transform infrared (FTIR) and Raman spectrometer technique. Meanwhile their structure was characterized by X-ray diffraction technique (XRD). Field emission scanning electron microscope (FE-SEM) was used to observe particle morphology and chemical compositions was investigated by Energy-dispersive X-ray spectroscopy (EDX). Photocatalytic performance of BiVO<inf>4</inf> nanopowder was studied by decomposition of organic dye as organic pollutant model using visible light to excite photocatalyst materials. It was found that sonochemical irradiation time supplied during chemical process can effectively expedite the formation of BiVO<inf>4</inf> nanoparticle. The optimized condition to obtain the product with enhanced photocatalytic performance of 60% decomposition is achieved as the sample was prepared at 40 min ultrasonic irradiation.
Some of the metrics are blocked by your
consent settings
Glass-Ceramic Na3+x[(Zr/Cr)x(Sc/Ti)2-x(PO4)3 Electrolyte Materials for Na-Ion Full-Cell Application
(2023-01-01)
Gandi, Shyam Sundar
;
Katta, Vamsi Krishna
;
Jayasankar, C. K.
;
Pecharapa, Wisanu
;
Ravuri, Balaji Rao
Na<inf>3+x</inf>[(Zr/Cr)<inf>x</inf>(Sc/Ti)<inf>2-x</inf>(PO<inf>4</inf>)<inf>3</inf>] glass-ceramic material compositions containing NASICON-type crystalline phases might be a good candidate as an efficient electrolyte exclusively for Na-ion batteries. All-solid-state Na-ion full cells are designed with the three-layered pellets (NaCo<inf>0.7</inf>(VO)<inf>0.3</inf>PO<inf>4</inf>/Na<inf>3.5</inf>Zr<inf>0.5</inf>Sc<inf>1.5</inf>(PO<inf>4</inf>)<inf>3</inf> (NZSP) and Na<inf>3.5</inf>Cr<inf>0.5</inf>Ti<inf>1.5</inf>(PO<inf>4</inf>)<inf>3</inf>) (NCTP)/Na-metal foil). The electrical conductivity of the NZSPglass-ceramic powder sample achieves to be highest (9.47 × 10−04 S/cm) due to its lower grain boundary resistance (R <inf>gb</inf>) as observed in SEM images and also exhibits best electrochemical stability against conductivity when the samples kept in ambient air for 60 d. The charge/discharge capacities for the initial cycle are 75/69 and 60/53 mAhg−1 to both NZSP and NCTP of two full cells, respectively. However, discharge capacities are boosted up for both these cells without much loss in coulombic efficiency even after 10 cycles.
Some of the metrics are blocked by your
consent settings
A critical review and future prospects of Dy3+-doped glasses for white light emission applications
(2022-09-01)
Chandrappa, V.
;
Basavapoornima, Ch
;
Venkatramu, V.
;
Depuru, Shobha Rani
;
Kaewkhao, J.
Rare-earth (RE)-doped glassy systems gained much interest because of its wide variety of applications in numerous potential fields that include optical fibers, solid state lasers, optical amplifiers, optical thermometry sensors, waveguides, infrared detectors, spectral converters, display devices, and so on. Within RE ions, the trivalent dysprosium (Dy3+) ion is the most unique and characteristic ion to examine emission properties for white light and visible display emitting devices. Because, Dy3+ ion emits two intense emissions in the blue (~480 nm) and yellow (~575 nm) regions that are assigned to the 4F<inf>9/2</inf>→6H<inf>15/2</inf> and 4F<inf>9/2</inf>→6H<inf>13/2</inf> transition energies, respectively. Under the excitation of blue laser, Dy3+ ions exhibit attractive yellowish white fluorescence emission with higher quantum efficiency. In view of the importance of identifying efficient luminescent emitting materials for the development of optical devices, the present work is to investigate white light emission in new glass composition of B<inf>2</inf>O<inf>3</inf> +TeO<inf>2</inf> +SrCO<inf>3</inf> +ZnO+ZnF<inf>2</inf> +Dy<inf>2</inf>O<inf>3</inf> glass and in turn to compare and discuss these results with reported Dy3+:glasses. The tabulated reported data bank for 68 Dy3+:glasses at one place should prove valuable information for future work on rationalization of theoretical and practical point of view to enrich white light emission quantification, simulation and systemization.
Some of the metrics are blocked by your
consent settings
Tailoring the Emission Behavior of WO3 Thin Films by Eu3+ Ions for Light-Emitting Applications
(2023-01-01)
Kavitha, V. S.
;
Biju, V.
;
Gopchandran, K. G.
;
Praveena, R.
;
Jayasankar, C. K.
The article reports the successful fabrication of Eu3+-doped WO<inf>3</inf> thin films via the radio-frequency magnetron sputtering (RFMS) technique. To our knowledge, this is the first study showing the tunable visible emission (blue to bluish red) from a WO<inf>3</inf>:Eu3+ thin film system using RFMS. X-ray diffractograms revealed that the crystalline nature of these thin films increased upto 3 wt% of the Eu3+ concentration. The diffraction peaks in the crystalline films are matched well with the monoclinic crystalline phase of WO<inf>3</inf>, but for all the films’, micro-Raman spectra detected bands related to WO<inf>3</inf> monoclinic phase. Vibrational and surface studies reveal the amorphous/semi-crystalline behavior of the 10 wt% Eu3+-doped sample. Valence state determination shows the trivalent state of Eu ions in doped films. In the 400–900 nm regions, the fabricated thin films show an average optical transparency of ~51–85%. Moreover, the band gap energy gradually reduces from 2.95 to 2.49 eV, with an enhancement of the Eu3+-doping content. The doped films, except the one at a higher doping concentration (10 wt%), show unique emissions of Eu3+ ions, besides the band edge emission of WO<inf>3</inf>. With an enhancement of the Eu3+ content, the concentration quenching process of the Eu3+ ions’ emission intensities is visible. The variation in CIE chromaticity coordinates suggest that the overall emission color can be altered from blue to bluish red by changing the Eu3+ ion concentration.
Some of the metrics are blocked by your
consent settings
Characterization, X-ray absorption spectroscopic analysis and photocatalytic activity of Co/Zn co-doped TiO2 nanoparticles synthesized by one-step sonochemical process
(2021-10-01)
Mekprasart, Wanichaya
;
Pavasupree, Sorapong
;
Jayasankar, C. K.
;
Ravuri, Balaji Rao
;
Wattanawikkam, Chakkaphan
A novel one-step preparation of sonochemical method was applied to synthesize Co/Zn co-doped TiO<inf>2</inf> nanoparticles using a sonicator of 750 W, 20 kHz for 30 min at room temperature. The formation of the anatase TiO<inf>2</inf> phase for all as-prepared samples was observed from XRD results with a crystalline size in nanoscale. The use of ultrasound allowed for the successful doping of both Co and Zn into the TiO<inf>2</inf> lattice, which was confirmed by Synchrotron light including X-ray near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Ti K-edge, Co K-edge, and Zn K-edge XANES spectra exhibited the dominating +4, +2, and +2 valence state of Ti, Co, and Zn in as-prepared samples, respectively. A detailed XANES and EXAFS data analysis give strong evidence that the Co/Zn dopants partially replace the Ti atom of the TiO<inf>2</inf> host. The Co/Zn co-doping extends the light absorption of the host to the visible region and restricts the e+/h+ recombination. The photocatalytic activity of samples was tested for degradation of Rhodamine B dye solution under visible light irradiation. The as-synthesized of the co-doped catalyst was presented as highly efficient, with 2.5 and 5 times dye degradation compared with single-doped and bare TiO<inf>2</inf>.
Some of the metrics are blocked by your
consent settings
Photoluminescence and energy transfer studies in Ce3+ and Sm3+ activated P2O5+K2O+Al2O3+BaF2+NaF2 glasses for solid state lighting
(2020-01-01)
Rao, V. Rajeswara
;
Doddoji, Ramachari
;
Pecharapa, Wisanu
;
Kaewkhao, J.
;
Depuru, Shobha Rani
A color of blue-red emission by Ce3+ and Sm3+ activated fluorophosphate glasses (PKABfNf:P<inf>2</inf>O<inf>5</inf>+K<inf>2</inf>O + Al<inf>2</inf>O<inf>3</inf>+BaF<inf>2</inf>+NaF<inf>2</inf>) were successfully fabricated by using usual melt and sudden quenching method. The FTIR, SEM, EDS, luminescence spectra, the decay rates, and energy transfer (ET) mechanism in the co-doped (Ce3+,Sm3+):PKABfNf glasses were systematically investigated in detail. The luminescence spectra of co-doped glasses show broadband blue de-excitation that belongs to Ce3+ ions and it obviously intensify the red de-excitation of Sm3+ through an effective ET process. The decrease in lifetime could support the existence of ET between Ce3+ and Sm3+ in PKABfNf glasses. This ET from Ce3+ to Sm3+ can be proposed to be the interaction due to quadrupole-quadrupole, based on the Dexter's ET formula and Reisfeld's approximation. Furthermore, CIE chromaticity coordinates, color correlated temperature, color purity, ET luminous efficiency (η<inf>ET</inf>), critical energy transfer distance (R<inf>c</inf>), and ET parameter (Q) were calculated. The findings show that (Ce3+,Sm3+):PKABfNf glass might be a promising candidate in lighting field applications.
Some of the metrics are blocked by your
consent settings
Spectral characteristics of Pr3+-doped lead based phosphate glasses for optical display device applications
(2020-12-01)
Basavapoornima, Ch
;
Kesavulu, C. R.
;
Maheswari, T.
;
Pecharapa, Wisanu
;
Depuru, Shobha Rani
The present work concentrates on spectral analysis of Pr3+:lead phosphate (PPbKANPr) glasses for visible lasers and optical amplifier applications and these glasses were prepared by a melt-cast technique. Vibrational modes of PPbKANPr glasses have been analyzed through FTIR and Raman techniques. Based on the absorption spectrum and the renowned Judd-Ofelt (JO) formalism, the three JO parameters (Ω<inf>2,4,6</inf>) were calculated and then used to estimate the various radiative probabilities for characteristic excited fluorescent states of Pr3+. The derived JO parameters ( × 10−20 cm2) were found to be Ω<inf>2</inf> = 1.51, Ω<inf>4</inf> = 18.03 and Ω<inf>6</inf> = 19.81. The luminescence spectra exhibit emission bands in the visible region of 480–780 nm and with the increase of Pr3+ ion concentration, the emission intensities were decreased due to concentration quenching. The decay curves of the PPbKANPr glasses were measured with the 443 nm excitation, monitoring via the luminescence peak at 610 nm. The decay rates reveal bi-exponential trend with shortening of lifetimes with increasing of Pr3+ ion concentration. Near infrared luminescence properties were obtained with the excitation of Ar+ ion laser line (488 nm) and the spectrum consists of three emission bands covering from 800 nm to 1600 nm. The investigation of the results proved that the current PPbKANPr glasses are useful for visible lasers and optical amplifiers.
Some of the metrics are blocked by your
consent settings
Preparation of potassium tungsten bronze (KxWO3) for near-infrared shielding application via high-energy ball milling: Effect of milling time
(2026-07-15)
Pinthong, Phonlawee
;
Kansaard, Thanaphon
;
Songpanit, Maneerat
;
Jayasankar, C. K.
;
Mekprasart, Wanichaya
Potassium tungsten bronze (K<inf>x</inf>WO<inf>3</inf>), one of Near-infrared shielding application, with superior visible transmittance and near-infrared. In this work, potassium tungsten bronze particles were prepared by high energy ball milling method. X-ray diffraction technique was used to identify crystal structure of KWO powder. the morphology was observed with FE-SEM and TEM. The chemical state of tungsten was use XPS, and UV-vis-NIR spectrophotometer for optical property. The effect of prolongated milling time is effect on crystal structure change from starting materials to potassium tungsten bronze materials, particles size and optical property including Near infrared shielding and photochromic property.

Pecharapa, Wisanu

Filters

Settings

Sort By

Results per page