Synthesis and blue emission properties of Co-doped CdS semiconductor nanoparticles

2021 ◽  
Vol 01 ◽  
Author(s):  
Sangaraju Sambasivam ◽  
Yedluri Anil Kumar ◽  
Chandu V.V. Muralee Gopi ◽  
Venkatesha Narayanaswamy ◽  
Ihab M. Obaidat
Keyword(s):  
Band Gap ◽  
Blue Emission ◽  
Semiconductor Nanoparticles ◽  
Emission Peak ◽  
Photoluminescence Spectra ◽  
Blue Emission Peak ◽  
Cubic Structure ◽  
Strong Blue Emission ◽  
Xrd And Tem ◽  
Co Doped

Background: Cadmium sulfide (CdS) based semiconductors are of great interest for different high-end applications because it poses direct bandgap (2.42 eV). CdS are the primary constituent material in many applications, namely solar cells, electroluminescent, and quantum dot light-emitting diodes. Transition metal-doped CdS revealed considerable influence in the bandgap, photoluminescence properties, and peak energy upon increasing the metal content. Objective: In this work, we study the single-phase cubic structure of CdS. Photoluminescence spectra revealed a strong blue emission peak located at about 445 nm. Methods: We investigate the Co-doping CdS semiconductor nanoparticles prepared via the chemical co-precipitation method using thiophenol as a template, 300 °C/2h in vacuum optimum temperature, and annealing period to yield nanosized particles. Morphology and structural studies of the particles were using XRD and TEM, respectively. Results: XRD and TEM studies for the calcined samples revealed a cubic structure. The crystalline size was in the range of 10-17 nm. Thermo gravimetric analysis (TGA) was employed to stabilize the temperature of annealing for the samples. Photoluminescence spectra revealed a strong blue emission peak around 445 nm, indicating surface states within the band gap region, a characteristic feature of nanoparticles. The blue shift in the spectra and the band gap value of Co-doped CdS nanoparticles was estimated using UV-vis absorption spectra. Conclusion: XRD analysis indicated zinc blende structure, and the intensity decreased with increasing Co content. TEM images show that the particles are spherical with average sizes around 13 nm. Luminescence of the synthesized nanoparticles exhibited blue emission between 400 – 500 nm, with the peak located at about 445 nm. The emission intensity increased with the increase in Co concentration.

Synthesis and Characterization of Lightweight Beryllium Chloro Silicate Phosphor

2022 ◽  
pp. 89-100
Author(s):  
Khushbu Sharma
Keyword(s):  
Blue Emission ◽  
Emission Peak ◽  
Excitation Band ◽  
Photoluminescence Spectra ◽  
Strong Emission ◽  
White Leds ◽  
Long Afterglow ◽  
Silicate Phosphor ◽  
Low Weight

In this chapter, low weight barium-based cholorsilicate Ba5Cl6Si2O6:Eu2+ is prepared through a solid-state reaction. To confirm the structure of the synthesized phosphors, powder photographs were obtained using an x-ray diffractometer. Photoluminescence spectra and FTIR spectra were recorded. Photoluminescence spectra are studied. The emission peak is observed at 407 nm at excitation 275 nm. The intense violet-blue emission is obtained. The broad excitation band and strong emission indicate that Ba5Cl6Si2O6:Eu2+could be a good phosphor candidate for blue LED and white LEDs. Decay curve indicates the phosphor has a long afterglow feature.

Combustion Synthesis and Luminescent Properties of Eu3+ and Dy3+ Co-Doped Amorphous SrAl2O4

2013 ◽  
Vol 538 ◽  
pp. 58-62 ◽  
Author(s):  
Bao Gai Zhai ◽  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Blue Emission ◽  
Luminescent Properties ◽  
Yellow Emission ◽  
Photoluminescence Spectra ◽  
Solution Combustion ◽  
X Ray ◽  
Emission Color ◽  
Blue Background ◽  
Good Environment ◽  
Co Doped

Trivalent Eu and Dy ions co-doped amorphous strontium aluminate oxide (SrAl2O4:Eu3+Dy3+) were synthesized through solution combustion route. The phase of the synthesized compound was examined with the X-ray diffractometry. The photoluminescence spectra of the amorphous SrAl2O4:Eu3+Dy3+ has shown that the sharp blue emission of Dy3+ at 483 nm, the sharp yellow emission of Dy3+ at 570 nm and the sharp red emission of Eu3+ at 615 nm can be integrated into the broad blue background emission of the amorphous host. The results indicate that the amorphous SrAl2O4 host can provide good environment to tune the emission color for the SrAl2O4:Eu3+Dy3+.

Effect of the Sols’ Zinc Ions’ Concentration on Structural and Optical Properties of (Cu, Al) Co-Doped ZnO Thin Film by Sol - Gel Method

2014 ◽  
Vol 496-500 ◽  
pp. 206-209
Author(s):  
Ying Xiang Yang ◽  
Hong Lin Tan ◽  
Qing Nan Shi
Keyword(s):  
Sol Gel ◽  
Blue Emission ◽  
Electron Transition ◽  
Photoluminescence Spectra ◽  
Zinc Vacancy ◽  
Structural And Optical Properties ◽  
Gel Method ◽  
Sol Gel Method ◽  
Doped Zno ◽  
Co Doped

(Cu-Al) co-doped ZnO thin films were deposited on glass substrate by the sol-gel method using the spin coating technique.The crystalline phase structure of the films were analyzed by X-raydiffraction.The photoluminescence spectra of samples were measured by fluorescence spectrophotometer.The results show that these films have a compact hexagonal wurtzitetype structure. five peaks have been observed from the PL spectra of the all samples,367nm (3.38eV),398nm (3.12eV),450nm (2.759eV),483nm (2.57eV) and 468nm (2.653eV).It is concluded that the violet peak may correspond to the excit on emission,the blue emission corresponds to the electron transition from the bottom of the conduction band to the accept or level of zinc vacancy.

Blue Upconversion Luminescence from Phosphor Tm3+/Yb3+ Co-Doped Gd2Mo3O9

2013 ◽  
Vol 683 ◽  
pp. 3-6
Author(s):  
Jia Yue Sun ◽  
Bing Xue ◽  
Guang Chao Sun ◽  
Dian Peng Cui ◽  
Hai Yan Du
Keyword(s):  
Solid State ◽  
Upconversion Luminescence ◽  
Blue Emission ◽  
Solid State Reaction Method ◽  
Solid State Lighting ◽  
Red Emission ◽  
Reaction Method ◽  
X Ray ◽  
Strong Blue Emission ◽  
Co Doped

The upconversion (UC) luminescence properties of phosphor Tm3+/Yb3+co-doped Gd2Mo3O9were investigated in detail. Tm3+/Yb3+co-doped Gd2Mo3O9was prepared by solid-state reaction method using Na2CO3as flux and characterized by powder X-ray diffractometry. Under 980nm excitation, Tm3+/Yb3+co-doped Gd2Mo3O9has exhibited a weak red emission near 651nm and strong blue emission at 476nm. Tm3+/Yb3+co-doped Gd2Mo3O9phosphor has been considered as a better candidate in solid-state lighting applications.

Blue Emission Peak of GeO[sub 2] Particles Grown Using Thermal Evaporation

2010 ◽  
Author(s):  
Kamal Mahir Sulieman ◽  
M. M. Jumidali ◽  
M. R. Hashim ◽  
A. K. Yahya ◽  
Shah Alam
Keyword(s):  
Thermal Evaporation ◽  
Blue Emission ◽  
Emission Peak ◽  
Blue Emission Peak

Luminescence Reducing Mechanism of Cd Doped Y2O2S:Ti,Cd Long Afterglow Phosphor

2007 ◽  
Vol 336-338 ◽  
pp. 604-606
Author(s):  
Peng Yue Zhang ◽  
Zhang Lian Hong ◽  
Xian Ping Fan ◽  
Min Quan Wang
Keyword(s):  
Solid State ◽  
Trap Depth ◽  
Emission Peak ◽  
Trap Level ◽  
Structure Defect ◽  
Photoluminescence Spectra ◽  
Ion Content ◽  
Long Afterglow ◽  
Chromaticity Coordinate ◽  
Co Doped

Y1.97-xTi0.03CdxO2S (0≤x≤0.06) phosphors with long afterglow were synthesized by solid-state reaction. The photoluminescence spectra, decay curves, thermoluminescnece spectra and Chromaticity coordinate curves were investigated. Results showed that the luminescence and afterglow intensity of Y1.97-xTi0.03CdxO2S (0≤x≤0.06) reduced gradually with increasing Cd2+ ion content while the shape and position of emission peak remain unchanged. The Chromaticity coordinate of present phosphor keeps at (0.5497,0.4415). Furthermore, based on the results of thermoluminescence curves of Ti, Cd single doped and co-doped Y2O2S phosphors, the doped Cd ion reduces the inherent trap depth of Ti single doped Y2O2S:Ti, and induces simultaneously a new trap level in Y2O2S:Ti,Cd phosphor. Thus, it was proposed that the introduced new structure defect by Cd2+ ions should be responsible for the reducing luminescence and afterglow property.

scholarly journals Influence of Blue-Emission Peak Wavelength on the Reliability of LED Device

2012 ◽  
Vol 21 (3) ◽  
pp. 164-170 ◽  
Author(s):  
S.H. Han ◽  
Y.J. Kim ◽  
J.H. Kim ◽  
J.Y. Jung ◽  
H.C. Kim ◽  
...  
Keyword(s):  
Blue Emission ◽  
Emission Peak ◽  
Peak Wavelength ◽  
Blue Emission Peak

Carbon Quantum Dots as Fluorescence Turn-Off-On Probe for Detecting Fe3+ and Ascorbic Acid

2020 ◽  
Vol 20 (6) ◽  
pp. 3340-3347 ◽  
Author(s):  
Yong Zhang ◽  
Yanteng Xiao ◽  
Yujuan Zhang ◽  
Yingte Wang
Keyword(s):  
Quantum Dots ◽  
Ascorbic Acid ◽  
Fluorescence Probe ◽  
Fluorescent Sensor ◽  
Blue Emission ◽  
Carbon Quantum Dots ◽  
Emission Peak ◽  
Dual Function ◽  
Blue Emission Peak ◽  
Bright Blue

This work describes a “turn-off-on” fluorescence probe based on carbon quantum dots for sensing Fe3+ and ascorbic acid. The carbon quantum dots are prepared by hydrothermal method using a biocarbon source of black sesame. When excited at 355 nm, the carbon quantum dots show a strong bright blue emission peak centered at 438 nm. Obviously, the decrease of the fluorescence intensity of carbon quantum dots can be seen upon addition of Fe3+. Interestingly, the fluorescence quenching can be regained after the addition of ascorbic acid. The mechanism is that the added Fe3+ was destroyed by reductive ascorbic acid because of the redox reaction between ascorbic acid and Fe3+, making the fluorescence of the system recovered. The obtained curves are linear for Fe3+ and ascorbic acid over the range 50–1500 μM and 32.2–987.6 μM, respectively. The detection limits for Fe3+ and ascorbic acid are 2.78 μM and 0.0344 μM, respectively. Thus the carbon quantum dots can be used as a dual-function fluorescent sensor to achieve sensitive detection of Fe3+ and ascorbic acid.

The influence of Co content on the luminescence properties of Co-doped ZnO nanoparticles

2018 ◽  
Vol 32 (10) ◽  
pp. 1850112
Author(s):  
Shuxia Guo ◽  
Haitao Jiang
Keyword(s):  
Zno Nanoparticles ◽  
Blue Emission ◽  
Green Emission ◽  
Content Increase ◽  
Edge States ◽  
Photoluminescence Spectra ◽  
Uv Emission ◽  
Doped Zno ◽  
Co Precipitation ◽  
Co Doped

Co-doped ZnO nanoparticles have been synthesized by co-precipitation technique. Photoluminescence spectra change in the range from 350 nm to 600 nm and remain unchanged at about 690 nm with the Co content increase. The UV emission is assigned to exciton emission. The density of band-edge states increases with Co content. The blue emission could be ascribed to the recombination of electrons in Co[Formula: see text] ions and holes in the valence band, whose relative intensity and full-width at half-maximum (FWHM) increase with the increase of cobalt concentration. The red emission results from the intra-d-shell emission at Co, which is independent of Co content. The relative density and energy-level position of green emission centers are also influenced by Co content.

Microwave Hydrothermal Synthesis of GaN Nanorods

2011 ◽  
Vol 675-677 ◽  
pp. 251-254 ◽  
Author(s):  
Dong Li ◽  
Fen Wang ◽  
Jian Feng Zhu ◽  
Da Wei Liu ◽  
Xiao Feng Wang ◽  
...  
Keyword(s):  
Raw Materials ◽  
Blue Emission ◽  
Crystal Defects ◽  
Emission Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Hydrothermal ◽  
Blue Emission Peak ◽  
Hexagonal Nanorods ◽  
Optical Applications

The GaOOH Nanocrystal rods were successfully synthesized by microwavehydrothermal method using Ga2O3 ,HNO3 and NH3·H2O as raw materials. Simple heat treatment of GaOOH in the flow of NH3 gas leads to the formation of submicron GaN rods even at 800°C through GaOOH. The resultant GaOOH and GaN nanomaterials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The growth mechanism of GaOOH and GaN was proposed. The results indicate that the as synthesized GaN were hexagonal nanorods with average aspects ratio of 5:1(diameter 800 nm and length about 4μm). Photoluminescence spectrum shows that a blue emission peak originates at 473.5 nm, indicating that the GaN nanorods displayed luminescence emission in the blue-violet region, which was related to crystal defects, and may be helpful for electro-optical applications of GaN material.

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