scholarly journals Effect of Reaction Time on Optical Properties of CsPbBr3 Perovskite Nanocrystals

2021 ◽  
Vol 30 (5) ◽  
pp. 152-155
Author(s):  
Sung Hun Kim ◽  
Yong-Ryun Jo ◽  
Yong Bin Kim ◽  
Ju Seok Kim ◽  
Sang-Youp Yim ◽  
...  
Keyword(s):  
Optical Properties ◽  
Reaction Time ◽  
Perovskite Nanocrystals

Effect of reaction time and different solvents ratios on the formed phases and optical properties of formamidinium lead bromide

2021 ◽  
Vol 119 ◽  
pp. 111318
Author(s):  
A.M. El-naggar ◽  
Mohamed Bakr Mohamed ◽  
Zein K. Heiba ◽  
Rawabi E. Alatawi ◽  
A.M. Kamal ◽  
...  
Keyword(s):  
Optical Properties ◽  
Reaction Time ◽  
Lead Bromide

Suppression of Halide Migration and Immobile Ionic Surface Passivation for Blue Perovskite Light-Emitting Diodes

2022 ◽  
Author(s):  
Chan Beom Park ◽  
Yun Seop Shin ◽  
Yung Jin Yoon ◽  
Hyungsu Jang ◽  
Jung Geon Son ◽  
...  
Keyword(s):  
Optical Properties ◽  
Light Emitting Diodes ◽  
Surface Passivation ◽  
Optoelectronic Properties ◽  
Light Emitting ◽  
Perovskite Nanocrystals

Cs-based perovskite nanocrystals (PeNCs) have been considered to be superb emitters for perovskite light-emitting diodes (PeLEDs) due to their remarkable optoelectronic properties. Still, poor optical properties are mainly attributed to...

Synthesis, Optical Properties, and Exciton Dynamics of Organolead Bromide Perovskite Nanocrystals

2015 ◽  
Vol 119 (47) ◽  
pp. 26672-26682 ◽  
Author(s):  
Binbin Luo ◽  
Ying-Chih Pu ◽  
Yi Yang ◽  
Sarah A. Lindley ◽  
Ghada Abdelmageed ◽  
...  
Keyword(s):  
Optical Properties ◽  
Exciton Dynamics ◽  
Perovskite Nanocrystals

Size-Controlled Microwave-Assisted Synthesis of Water-Dispersible Cd(Se,S) Quantum Dots for Potential Biological Applications

2015 ◽  
Vol 1784 ◽  
Author(s):  
E. Calderón-Ortiz ◽  
S. Bailón-Ruiz ◽  
L. Alamo-Nole ◽  
J. Rodriguez-Orengo ◽  
O. Perales-Perez
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Quantum Confinement Effect ◽  
Reactive Oxygen Species Generation ◽  
Size Control ◽  
Average Crystallite Size ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted

ABSTRACTNanomedicine is fostering significant advances in the development of platforms for early detection and treatment of diseases. Nanoparticles (NPs) like quantum dots (QDs) exhibit size-dependent optical properties for light-driven technologies, which might become important in bio-imaging, sensing and photo-dynamic therapy (PDT) applications. The present research addresses the synthesis of water-stable Cd-based QDs via a Microwave-Assisted synthesis approach using cadmium sulfate salt, and thioglycolic acid as Cd- and S-precursors, respectively. Selenide ions were available by reductive leaching of metallic Selenium in Sodium bisulfite solution. The size control and the tunability of the optical properties were achieved by a suitable control of the reaction temperature (in the 140°C- 190°C range) and reaction time (10 minutes-40 minutes). X-ray diffraction analyses suggested the development of a CdSe,S face cubic centered structure; the broadening of the diffraction peaks indicated the presence of very small nanocrystals in the samples. The average crystallite size was estimated at 5.50 nm ± 1.17nm and 3.72 nm ± 0.04 nm, for nanoparticles synthesized at 180°C after 40 minutes or 10 minutes of reaction, respectively. HRTEM images confirmed the crystalline nature and the small size of the synthesized nanocrystals. In turn, the exciton was red-shifted from 461nm to 549 nm when the reaction temperature was prolonged from 140°C to 190 °C, suggesting the crystal growth. The corresponding band gap values were approximately 2.2 eV, confirming the quantum confinement effect (bulk value 1.74eV). This red shift was also evidenced in PL measurements where the main emission peak was shifted from 507 nm to 564 nm when the samples were excited at 420 nm. A narrow size-tunable emission also was supported by the full width at half maximum (∼ 45 nm) for the synthesized nanocrystals. The reactive oxygen species generation capability of as-synthesized QDs was also investigated. The correlation between the particle size and the generation of (ROS) by the degradation of methylene blue was evident with a reduction of MB concentration from 10μM to 7.5μM and 6.7μM after 15 minutes of UV irradiation for reaction time of 10 min. and 40 min. respectively. No additional degradation was noticed after 60 minutes of irradiation.

CONTROLLED SYNTHESIS OF THE ZnWO4 NANOSTRUCTURE AND STUDY OF THEIR STRUCTURAL AND OPTICAL PROPERTIES

2012 ◽  
Vol 21 (01) ◽  
pp. 1250002 ◽  
Author(s):  
NGUYEN MANH HUNG ◽  
LAM THI HANG ◽  
NGUYEN VAN KHANH ◽  
DU THI XUAN THAO ◽  
NGUYEN VAN MINH
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Optical Properties ◽  
Reaction Time ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Calcination Time ◽  
Transmission Electron ◽  
Pure Phase ◽  
Size And Morphology

We investigate the effects of calcination time and concentration of solution on the structure, as well as optical properties in ZnWO4 nanopowder prepared by hydrothermal method. The prepared powder were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman scattering, optical absorption and photoluminescent spectroscopy (PL). It is shown that the grain size and morphology of ZnWO4 nanopowder can be controlled by adjusting the reaction time as well as the concentration of the solution. The resultant sample is a pure phase of ZnWO4 without any impurities. The result showed that the optical property of ZnWO4 nanopowders depend on their grain size. The optical band gap becomes narrower as the reaction time or concentration of solution is increased. The improved PL properties of the ZnWO4 crystallites can be obtained with the optimal concentration of the solution.

scholarly journals Tailoring Blue-Green Double Emissions in Carbon Quantum Dots via Co-Doping Engineering by Competition Mechanism between Chlorine-Related States and Conjugated π-Domains

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 635 ◽  
Author(s):  
Xue Sun ◽  
Huilian Liu ◽  
Lili Yang ◽  
Xinying Wang ◽  
Weiqiang Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Reaction Time ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Carbon Quantum Dots ◽  
Confinement Effect ◽  
Co Doping ◽  
Photoelectric Properties ◽  
Co Doped

Representing single-layer to tens of layers of graphene in a size less than 30 nm, carbon quantum dots (CQDs) is becoming an advanced multifunctional material for its unique optical, electronic, spin and photoelectric properties induced by the quantum confinement effect and edge effect. In present work, upon co-doping engineering, nitrogen and chlorine co-doped CQDs with uniquely strong blue-green double emissions are developed via a facile and one-pot hydrothermal method. The crystalline and optical properties of CQDs have been well manipulated by tuning the mole ratio of nitrogen/chlorine and the reaction time. The characteristic green emission centered at 512 nm has been verified, originating from the chlorine-related states, the other blue emissions centered at 460 nm are attributed to the conjugated π-domain. Increasing the proportion of 1,2,4-benzentriamine dihydrochloride can effectively adjust the bandgap of CQDs, mainly caused by the synergy and competition of chlorine-related states and the conjugated π-domain. Prolonging the reaction time promotes more nitrogen and chlorine dopants incorporate into CQDs, which inhibits the growth of CQDs to reduce the average size of CQDs down to 1.5 nm, so that the quantum confinement effect dominates into play. This work not only provides a candidate with excellent optical properties for heteroatoms-doped carbon materials but also benefits to stimulate the intensive studies for co-doped carbon with chlorine as one of new dopants paradigm.

Solvothermal Growth of Flower-Like Morphology from Nanorods of Copper Sulfides

2008 ◽  
Vol 8 (3) ◽  
pp. 1523-1527 ◽  
Author(s):  
Poulomi Roy ◽  
Suneel Kumar Srivastava
Keyword(s):  
Optical Properties ◽  
Reaction Time ◽  
Copper Sulfide ◽  
Solvothermal Synthesis ◽  
Stoichiometric Composition ◽  
X Ray Diffraction ◽  
Reaction Duration ◽  
X Ray ◽  
Copper Sulfides ◽  
Diffraction Patterns

The present work reports the effect of reaction time on solvothermal synthesis of copper sulfides from CuCl2·2H2O and thiourea with various compositions and morphologies using ethylenediamine as solvent at 120 °C. X-ray diffraction patterns of the products at different durations shows the development of different stoichiometric composition of copper sulfides in where Cu:S ratio increases from 1.39 to 1.79 indicating transformation of Cu39S28 to Cu7S4. As inferred by EDX and XPS studies of the final products. SEM shows the growth of bundles of nanorods of length ≈1 μm and diameter in nanometer range are observed after 6 h. On increasing the reaction duration to 9 h, nanorods tends to combines with each other and growth occurs in six directions and after 12 h leads to the formation of flower-like morphology of copper sulfide. The optical properties of these products also have been studied.

scholarly journals Solvothermal synthesis of Mn-doped CsPbCl3 perovskite nanocrystals with tunable morphology and their size-dependent optical properties

RSC Advances ◽  
2019 ◽  
Vol 9 (67) ◽  
pp. 39315-39322 ◽  
Author(s):  
Chang Liu ◽  
Jing Lin ◽  
Wei Zhai ◽  
Zhikai Wen ◽  
Xin He ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solvothermal Synthesis ◽  
Solvothermal Reaction ◽  
Perovskite Nanocrystals ◽  
Size Dependent ◽  
Mn Doped ◽  
Tunable Morphology

A facile solvothermal reaction strategy was developed to obtain Mn-doped CsPbCl3 nanocrystals with tunable morphology and optical properties.

scholarly journals Composition-, Size-, and Surface Functionalization-Dependent Optical Properties of Lead Bromide Perovskite Nanocrystals

2020 ◽  
Vol 11 (6) ◽  
pp. 2079-2085 ◽  
Author(s):  
Palvasha Ijaz ◽  
Muhammad Imran ◽  
Márcio M. Soares ◽  
Hélio C. N. Tolentino ◽  
Beatriz Martín-García ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Functionalization ◽  
Perovskite Nanocrystals ◽  
Lead Bromide
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