scholarly journals Synthesis of brightly luminescent colloidal formamidinium lead bromide perovskite FAPbBr3 nanoplatelets with tunable emission

2021 ◽  
Vol 348 ◽  
pp. 01015
Author(s):  
Nabila Jarmouni ◽  
Marco Tomaiuolo ◽  
Alessio Gabbani ◽  
Francesco Pineider ◽  
Rajaa Bassam ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Volume Ratio ◽  
Green Emission ◽  
Colloidal Solutions ◽  
Uniform Size ◽  
Quantum Size ◽  
Room Condition ◽  
Color Tunable ◽  
Lead Bromide ◽  
Display Technology

Hybrid halide perovskites are semicondoctor materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology. They have size-tunable emissions due to quantum size effects. In this work, the Formamidinium Lead Bromide perovskite CH(NH2)2PbBr3 nanoplatelets (NPLs) were successfully synthesized by ligand-assisted reprecipitation method under room condition, in which the emission color-tunability was realized via quantum size effect without anion–halide mixing, by varying the oleylamine to oleic acid volume ratio as surfactants, while the total amount of oleic acid remained unchanged. We are able to adjust the optical proprieties of FAPbBr3 NPLs and, consequently, their structural properties. The obtained colloidal solutions of FAPbBr3 nanoplatelets with uniform size exhibited different photoluminescence wavelengths covering the spectral region from 440 to 525 nm. The maximum absolute PL quantum yield (PLQY) of the green emission was measured to be as high as 80% at room temperature. The size of FAPbBr3 NPLs could be effectively tuned from 15.5 to 38.1 nm with an increase in the oleylamine and oleic acid ligands ratio.

scholarly journals Development of Er3+, Yb3+ Co-Doped Y2O3 NPs According to Yb3+ Concentration by LP–PLA Method: Potential Further Biosensor

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 150
Author(s):  
Cheol-Woo Park ◽  
Dong-Jun Park
Keyword(s):  
Pulsed Laser ◽  
Green Emission ◽  
Biological Imaging ◽  
Additive Concentration ◽  
Uniform Size ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Diagnostic Applications ◽  
Ceramic Targets ◽  
Co Doped

As diagnostic biosensors for analyzing fluids from the human body, the development of inorganic NPs is of increasing concern. For one, nanoceramic phosphors have been studied to meet the increasing requirements for biological, imaging, and diagnostic applications. In this study, Y2O3 NPs co-doped with trivalent rare earths (erbium and ytterbium) were obtained using a liquid phase–pulsed laser ablation (LP–PLA) method after getting high density Er, Yb:Y2O3 ceramic targets by Spark plasma sintering (SPS). Most NPs are under 50 nm in diameter and show high crystallinity of cubic Y2O3 structure, containing (222), (440), and (332) planes via HR–TEM. Excitation under a 980 nm laser to a nanoparticle solution showed 525 and 565 nm green, and 660 nm red emissions. The green emission intensity increased and decreased with increasing Yb3+ additive concentration, when the red spectrum continuously strengthened. Utilizing this study’s outcome, we suggest developing technology to mark invisible biomolecules dissolved in a solvent using UC luminescence of Er3+, Yb3+ co-doped Y2O3 NPs by LP–PLA. The LP–PLA method has a potential ability for the fabrication of UC NPs for biosensors with uniform size distribution by laser parameters.

Controlled Formation of Quantum Size Metal and Semiconductor Particles from Aqueous Solutions

1990 ◽  
Vol 206 ◽  
Author(s):  
Ramesh C. Patel ◽  
Jovan Nedeljkovic ◽  
Olga Micic
Keyword(s):  
Aqueous Solutions ◽  
Chemical Reduction ◽  
Deposition Process ◽  
Metallic Silver ◽  
Uniform Size ◽  
Quantum Size ◽  
Spherical Silica ◽  
Reduction Methods ◽  
Spherical Silica Particles ◽  
Excimer Laser Irradiation

ABSTRACTPhotochemical and chemical reduction methods are described for the controlled formation of metallic silver in aqueous solutions. The former approach is capable of generally depositing a number of metals. When spherical silver bromide particles are the substrates, the resulting silver coated composite particles exhibit optical absorption spectra which vary with the coat thickness as theoretically predicted. In the case of spherical silica particles of uniform size, it was possible to produce both quantum size silver particles supported on silica, as well as a silver coat of variable thickness, depending on the rate of the deposition process. In addition to silica, substrates such as latex and chromium hydroxide could be used.CdS particles with two different particle diameters (50–200 Å and < 30 Å) were subjected to 308 nm excimer laser irradiation at 77 K, and the subsequent charge carrier processes studied by ESR. Dramatic differences in the ESR signals as a function of decreasing particle size could be observed, consistent with the localization of charge carriers on numerous surface sites.

Rapid Synthesis of Non-Crosslinked and Monodisperse Polystyrene Microspheres

2013 ◽  
Vol 634-638 ◽  
pp. 2222-2227
Author(s):  
Chang Ming Ye ◽  
Yan Qin Yang ◽  
Feng Dong ◽  
Li Li ◽  
Xi Long Hao ◽  
...  
Keyword(s):  
Dispersion Polymerization ◽  
Monomer Concentration ◽  
Volume Ratio ◽  
Polymerization Process ◽  
Polystyrene Microspheres ◽  
Fenton Reagent ◽  
Uniform Size ◽  
Transmission Electron ◽  
New Synthesis ◽  
Monodisperse Polystyrene

Non-crosslinked and monodisperse polystyrene (PS) microspheres showing uniform size were synthesized by using a dispersion polymerization technique in the presence of the Fenton reagent (FeSO4/H2O2) as an initiator. The effects of stabilizer dosage, monomer concentration, volume ratio of dispersion medium and reaction time on both the morphology and dispersity of PS microspheres were investigated. The results of transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM) indicated that the obtained PS microspheres are perfect with uniform size of about 170 nm under the optimum experimental condition. On the basis of the experimental results, the mechanism of PS polymerization was proposed, which should be helpful to guide the preparation of polymer microspheres with desired uniform size. In comparison with the conventional emulsion polymerization, this new synthesis technique with the Fenton reagent exhibits some advantages such as being a simple and fast polymerization process without deoxygenation.

Isoprene and Rubber. Part 41. The Hydrogenation of Rubber and Balata

1934 ◽  
Vol 7 (3) ◽  
pp. 496-502
Author(s):  
H. Staudinger ◽  
E. O. Leupold
Keyword(s):  
Molecular Weight ◽  
Particle Sizes ◽  
Colloidal Solutions ◽  
Uniform Size ◽  
Micellar Structure ◽  
Molecular Weights ◽  
Rubber Particles ◽  
Rubber Part ◽  
Points Of View ◽  
Molecular Substances

Abstract Viscosity measurements of dilute solutions of rubber and of balata led to the following values for the size and form of the molecules of these hydrocarbons. It is therefore not a question of definition whether the particle sizes shown above are to be regarded as the molecular or the micellar weights of these substances, for here the concept of molecular weight has the same significance as in the case of lower molecular substances, i. e., the molecule comprises the sum of all atoms combined by normal, i. e., homopolar atoms. The only difference between low and high molecular substances is that low molecular substances are composed of molecules of uniform size, whereas high molecular substances are a mixture of homologous polymers, so that the values above refer to average molecular weights. These results, which explain the nature of colloidal solutions of rubber, are at variance with the views of most investigators of colloids, who ascribe a micellar structure to the rubber particles, and in this way explain the property which rubber has of forming colloidal solutions. This makes clear why until very recently explanations of the constitution of rubber have been open to question among these particular investigators themselves. In order to lend further support to our opinion, the reduction of rubber and balata and low molecular homologous polymeric hydrocarbons was undertaken from certain points of view, as shown in the work which follows.

Alveolar surface area-to-lung volume ratio in oleic acid-induced pulmonary edema

1996 ◽  
Vol 80 (3) ◽  
pp. 742-746 ◽  
Author(s):  
S. Suzuki ◽  
T. Akahori ◽  
N. Miyazawa ◽  
M. Numata ◽  
T. Okubo ◽  
...  
Keyword(s):  
Surface Tension ◽  
Oleic Acid ◽  
Pulmonary Edema ◽  
Lung Volume ◽  
Volume Ratio ◽  
Transpulmonary Pressure ◽  
Mean Free Path ◽  
Alveolar Surface Area ◽  
Alveolar Surface

It is unknown how the in vivo alveolar surface area-to-volume ratio (S/V) changes in low-pressure pulmonary edema. Here, the S/V is the area of the air-tissue interface per unit total volume (air plus tissue). We hypothesized that in oleic acid (OA)-induced edema inactivation of the pulmonary surfactant may increase surface tension and decrease the S/V at any given lung volume. OA (0.04 mg/kg) was intravenously injected into dogs. We measured the in vivo S/V (equivalent to the inverse of optical mean free path by light-scattering stereology and the pressure-volume (PV) curve 60-90 min after OA administration. OA administration decreased the lung volume at each transpulmonary pressure and increased the wet-to-dry weight ratio. The S/V decreased after OA administration (optical mean free path increased). The air-filled PV curves shifted downward after OA, but the saline-filled PV curves after OA administration did not differ significantly from control saline-filled curves. The difference in transpulmonary pressure between air- and saline-filled PV curves (an index of the magnitude of surface tension) was increased in OA-induced pulmonary edema. This study suggests that in OA-induced pulmonary edema the alveolar surface tension increases and the S/V decreases, presumably due to inactivation of surfactant by serum leakage to alveoli.

Color Tunable Emission from Eu3+ and Tm3+ co-doped CsPbBr3 Quantum Dot Glass Nanocomposites

2021 ◽  
Author(s):  
Erdinc Erol ◽  
Orhan Kıbrıslı ◽  
Miray Çelikbilek Ersundu ◽  
Ali Erçin Ersundu
Keyword(s):  
Quantum Dots ◽  
Electrical Properties ◽  
Quantum Dot ◽  
Luminescent Materials ◽  
Optical And Electrical Properties ◽  
Color Tunable ◽  
Lead Bromide ◽  
Co Doped ◽  
Tunable Emission

Cesium lead bromide (CsPbBr3) quantum dots (QDs) have shown great potential in the field of luminescent materials owing to their superior optical and electrical properties. However, instability and lack of...

Brightly luminescent and color-tunable green-violet-emitting halide perovskite CH3NH3PbBr3 colloidal quantum dots: an alternative to lighting and display technology

2018 ◽  
Vol 20 (30) ◽  
pp. 19950-19957 ◽  
Author(s):  
Yonghao Liu ◽  
Quan Xu ◽  
Shuai Chang ◽  
Zhao Lv ◽  
Sheng Huang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Colloidal Quantum Dots ◽  
Inorganic Hybrid ◽  
Hybrid Perovskite ◽  
Color Tunable ◽  
Display Technology ◽  
Halide Perovskite ◽  
Optoelectronic Applications

Organic–inorganic hybrid perovskite (CH3NH3PbX3, X = Cl, Br, or I) quantum dots have become one of the most promising materials for optoelectronic applications.

Oleic acid-induced, controllable surface oxidation to enhance the photoresponse performance of Sb2Se3 nanorods

CrystEngComm ◽  
2020 ◽  
Vol 22 (37) ◽  
pp. 6189-6194
Author(s):  
Fan Guan ◽  
Linjie Li ◽  
Yusong Cui ◽  
Tingting Wang ◽  
Shaopeng Li ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Volume Ratio ◽  
Surface Oxidation ◽  
Optoelectronic Properties ◽  
Oxidation Level

The surface oxidation level of Sb2Se3 nanorods is tunable by varying the volume ratio of oleic acid during the synthesis and a modest oxidation level (20–30%) is found to be favorable for the optoelectronic properties of Sb2Se3.

Multicolor-Effects of Luminescing, Nanostructured Silicon After Spark-Processing in Pure and Composite Gases

1996 ◽  
Vol 452 ◽  
Author(s):  
M. H. Ludwig ◽  
A. Augustin ◽  
R. E. Hummel
Keyword(s):  
Laser Light ◽  
Blue Emission ◽  
Volume Ratio ◽  
Green Emission ◽  
Radiative Properties ◽  
Pure Oxygen ◽  
Processing Conditions ◽  
Pure Nitrogen ◽  
Silicon Based ◽  
Gas Pressures

AbstractSpark-processing has been shown recently to generate a silicon-based substance which intensely photoluminesces in the UV/blue or green spectral range, depending on whether the preparation was performed in flowing or stagnant air, respectively. This study reports about significant differences for the radiative properties of spark-processed silicon after preparations in oxygen, nitrogen, and mixtures of both gases. Whereas there is essentially no photoluminescence (PL) after processing in pure nitrogen, an orange PL band at 1.89 eV occurs after preparation in pure oxygen. The orange PL degrades with time and when exposed to laser light. Furthermore, it switches immediately to a more intense blue emission centered at 2.61 eV when the sample is subjected to lower gas pressures. A similar 2.6 eV PL is observed after heat treatments up to 350°C. If, however, spark-processing of Si is carried out in nitrogen and oxygen is added, a green PL arises, centered at 2.35 eV. Moreover, for a volume ratio of about 1:1 N2/O2 a PL band at 3.22 eV emerges, superimposing the green emission. Both bands are about two orders of magnitude more intense than the orange PL, when prepared under otherwise identical processing conditions.

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