Effect of alkali metal (Na, K) ion ratio on structural, optical and photoluminescence properties of K0.5Na0.5NbO3 ceramics prepared by sol–gel technique

2021 ◽  
Vol 44 (1) ◽  
Author(s):  
SHAMMI KUMAR ◽  
NAGESH THAKUR
2009 ◽  
Vol 610-613 ◽  
pp. 616-620 ◽  
Author(s):  
Wei Wei Zhang ◽  
Jun Ying Zhang ◽  
Hui Wan ◽  
Zi Yu Chen ◽  
Tian Min Wang

Chromium-activated ZnGa2O4 nano-sized phosphor powder was prepared by the Sol-Gel technique using citric acid as chelator, and the microstructure and luminescent property were studied. The host ZnGa2O4 belongs to the spinel structure and the ZnGa2O4:Cr3+ phosphor powder exhibited bright red emission band. The excitation bands with peak of maximum height at about 250 nm, 410 nm and 560 nm were related to the charge transfer (CT) of Ga-O, 4A2-4T1 and 4A2-4T2 transitions of Cr3+, respectively. Different quenching concentrations of the CT state and intrinsic excitation were discovered originating from different energy transfer schemes. Meanwhile, with the increasing of the calcining temperature the PLE spectrum exhibited an obvious blue-shift which is attributed to the enhancement of the crystal field.


2018 ◽  
Vol 32 (4) ◽  
pp. 1035-1042 ◽  
Author(s):  
K. Sunil Kumar ◽  
M. Ramanadha ◽  
A. Sudharani ◽  
S. Ramu ◽  
R. P. Vijayalakshmi

2007 ◽  
Vol 280-283 ◽  
pp. 541-544
Author(s):  
Bo Li ◽  
Ji Zhou ◽  
Rui Long Zong ◽  
Long Tu Li

Mn2+-doped Zn2SiO4 inverse opals were synthesized by sol-gel technique combined with the self-assembly of the opal template. Zn2SiO4:Mn2+ precursors were infiltrated into the interstices of the opal template assembled by polystyrene spheres. The polystyrene template was removed by calcining and nanocrystals of Mn2+-doped Zn2SiO4 were obtained in the void of opal template. The inverse opals show photonic crystal behavior and emit yellow light initially with the luminescent peak at 562 nm corresponding with the fact that β-phase is the dominant phase for nanocrystals less than 30nm. As the β-phase transformed to α-phase with the gradual increase of treating temperature and the growth of the crystal, the luminescence from Zn2SiO4:Mn2+ phosphors change from yellow to green.


Engineering ◽  
2010 ◽  
Vol 02 (12) ◽  
pp. 969-972
Author(s):  
Hiroyuki Nasu ◽  
Tomoyuki Yamauchi ◽  
Sachio Ninagawa ◽  
Daisuke Hirota ◽  
Tadanori Hashimoto ◽  
...  

2013 ◽  
Vol 1 (2) ◽  
pp. 59-69 ◽  
Author(s):  
Sarbjit Kaur ◽  
Niraj Bala ◽  
Charu Khosla
Keyword(s):  
Sol Gel ◽  

2011 ◽  
Vol 4 (3) ◽  
pp. 224-237 ◽  
Author(s):  
Aurica P. Chiriac ◽  
Loredana E. Nita ◽  
Iordana Neamtu ◽  
Manuela T. Nistor
Keyword(s):  
Sol Gel ◽  

2020 ◽  
Vol 5 (3) ◽  
pp. 236-251
Author(s):  
Eshwara I. Naik ◽  
Halehatty S.B. Naik ◽  
Ranganaik Viswanath

Background: Various interesting consequences are reported on structural, optical, and photoluminescence properties of Zn1-xSmxO (x=0, 0.01, 0.03 and 0.05) nanoparticles synthesized by sol-gel auto-combustion route. Objective: This study aimed to examine the effects of Sm3+-doping on structural and photoluminescence properties of ZnO nanoparticles. Methods: Zn1-xSmxO (x=0, 0.01, 0.03 and 0.05) nanoparticles were synthesized by sol-gel auto combustion method. Results: XRD patterns confirmed the Sm3+ ion substitution through the undisturbed wurtzite structure of ZnO. The crystallite size was decreased from 24.33 to 18.46 nm with Sm3+ doping. The hexagonal and spherical morphology of nanoparticles was confirmed by TEM analysis. UV-visible studies showed that Sm3+ ion doping improved the visible light absorption capacity of Sm3+ iondoped ZnO nanoparticles. PL spectra of Sm3+ ion-doped ZnO nanoparticles showed an orange-red emission peak corresponding to 4G5/2→6HJ (J=7/2, 9/2 and 11/2) transition of Sm3+ ion. Sm3+ ion-induced PL was proposed with a substantial increase in PL intensity with a blue shift in peak upon Sm3+ content increase. Conclusion: Absorption peaks associated with doped ZnO nanoparticles were moved to a longer wavelength side compared to ZnO, with bandgap declines when Sm3+ ions concentration was increased. PL studies concluded that ZnO emission properties could be tuned in the red region along with the existence of blue peaks upon Sm3+ ion doping, which also results in enhancing the PL intensity. These latest properties related to Sm3+ ion-doped nanoparticles prepared by a cost-efficient process appear to be interesting in the field of optoelectronic applications, which makes them a prominent candidate in the form of red light-emitting diodes.


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