Highly emissive MAPbBr3 perovskite QDs by ligand-assisted reprecipitation: the antisolvent effect

2021 ◽  
Author(s):  
Wallison Costa ◽  
Cristian Salla ◽  
Fernando Ely ◽  
Ivan Bechtold
Keyword(s):  
Reaction Time ◽  
Photophysical Properties ◽  
Green Emission ◽  
Precipitation Method ◽  
Uv Curable ◽  
Hybrid Perovskite ◽  
Absolute Quantum Yield ◽  
Synthetic Procedure ◽  
Solid Film ◽  
Down Conversion

Abstract A systematic study of the synthetic procedure to improve quantum efficiency of luminescent hybrid perovskite QDs through ligand-assisted precipitation method is presented. Particularly, the influence of the dielectric constant and dipole moment of the antisolvent on the reaction time and the photophysical properties of the QDs is highlighted. After evaluating the influence of antisolvents and optimizing experimental parameters such as reaction time and Pb excess of the precursor, colloidal crystalline MAPbBr3 QDs with exceptionally high absolute quantum yield up to 97.7% in solution and 69.1% in solid film were obtained. Finally, MAPbBr3 QDs precipitated from anisole were processed like UV-curable nanocomposite as efficient down conversion layer resulting in very narrow green emission LED.

Luminescence of Cu2+-Doped ZnSe Quantum Dots with Different Parameters

2010 ◽  
Vol 148-149 ◽  
pp. 1268-1272 ◽  
Author(s):  
Qun Wang ◽  
Fu Tian Liu ◽  
Qing Hui Jiang ◽  
Xiu Xiu Chen ◽  
Dong Zhi Wang
Keyword(s):  
Quantum Dots ◽  
Reaction Time ◽  
Aging Time ◽  
Green Emission ◽  
Average Diameter ◽  
Transmission Electron Microscopy Image ◽  
Precipitation Method ◽  
Molar Ratio ◽  
High Fluorescence ◽  
Co Precipitation

Cu2+-doped ZnSe quantum dots (ZnSe:Cu2+ QDs) are synthesized in aqueous solution via a co-precipitation method with thioglycolic acid (TGA) as a stabilizer. Green emission is observed under 365 nm UV excitation. X-ray diffraction patterns and transmission electron microscopy image show that ZnSe:Cu2+ QDs are sphalerite cubic structure, similar to round in shape, the average diameter is 6 nm. The concentration of Cu2+ ions and TGA, pH, reaction time and aging time have influences on optical properties of ZnSe:Cu2+ QDs. The luminescence of as-prepared products with different parameters is characterized using fluorescence spectrophotometer. The high fluorescence intensity has been got when the concentration of Cu2+ ions is 4.0% (molar ratio), TGA is 83.4 μl (mol ratio Zn: TGA=1:2), pH is 9.5, reaction time is 2h. The luminous intensity increases with the extension of aging time.

scholarly journals Achieving selectivity in porphyrin bromination through a DoE-driven optimization under continuous flow conditions

2020 ◽  
Author(s):  
Paolo Zardi ◽  
Michele Maggini ◽  
Tommaso Carofiglio
Keyword(s):  
Reaction Time ◽  
Design Of Experiment ◽  
Continuous Flow ◽  
Optimization Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Reaction Parameters ◽  
Synthetic Procedure ◽  
Relevant Factors ◽  
Post Functionalization

AbstractThe post-functionalization of porphyrins through the bromination in β position of the pyrrolic rings is a relevant transformation because the resulting bromoderivatives are useful synthons to covalently link a variety of chemical architectures to a porphyrin ring. However, single bromination of porphyrins is a challenging reaction for the abundancy of reactive β-pyrrolic positions in the aromatic macrocycle. We herein report a synthetic procedure for the efficient preparation of 2-bromo-5,10,15,20-tetraphenylporphyrin (1) under continuous flow conditions. The use of flow technology allows to reach an accurate control over critical reaction parameters such as temperature and reaction time. Furthermore, by performing the optimization process through a statistical DoE (Design of Experiment) approach, these parameters could be properly adjusted with a limited number of experiments. This process led us to a better understanding of the relevant factors that govern porphyrins monobromination and to obtain compound 1 with an unprecedent 80% yield.

scholarly journals Preparation and Characterization of a Novel Terbium Complex Coordinated with 10-Undecenoic Acid for UV-Cured Coatings

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Chenjie Jiao ◽  
Rong Zhong ◽  
Yanfang Zhou ◽  
Hongfei Zhang
Keyword(s):  
Rare Earth ◽  
Green Light ◽  
Precipitation Method ◽  
Rare Earth Complex ◽  
Terbium Complex ◽  
Uv Curable ◽  
Good Thermal Stability ◽  
Potential Applications ◽  
Undecenoic Acid ◽  
The Rare Earth

A UV-cured composite containing a rare earth complex was prepared for this study. First, the photoluminescent terbium complex was synthesized with a long-chain unsaturated fatty acid (10-Undecenoic acid) by a solution precipitation method, resulting in the 10-UA-Tb(III) complex. Its structure was proven by FTIR, elemental analysis, XRD, and TGA. The results indicated that the organic acid ligand successfully coordinated with the Tb3+ ion and that the complex had a chelate bidentate structure. The emission spectrum of the 10-UA-Tb(III) complex indicated that the complex can emit a bright green light with the unique luminescence of the Tb3+ ion. Furthermore, the luminescence properties of complexes with different ratios of Tb3+ and ligand were studied, and the ratio of Tb3+ and the ligand had an obvious impact on the luminescence intensity of the 10-UA-Tb(III) complex. Subsequently, the prepared rare earth complex was doped into a UV-cured coating in different proportions to obtain a UV-cured composite. The morphology of the rare earth UV-cured composite was observed by SEM. The images showed that the rare earth complex was dispersed uniformly in the polymer matrix. Moreover, the composites could emit fluorescence. Additionally, it has good thermal stability and compatibility with the resin. Therefore, these composites should have potential applications in UV curable materials, such as luminescence coatings.

Structural and Optical Properties of Pure NiO Nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO-ZnO Nanocomposites

2021 ◽  
Vol 14 (5) ◽  
pp. 409-417
Keyword(s):  
Nickel Oxide ◽  
Green Emission ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Nio Nanoparticles ◽  
Structural And Optical Properties ◽  
Suitable Material ◽  
Structure Morphology ◽  
Average Grain Size ◽  
Co Precipitation

Abstract: Pure nickel oxide (NiO) nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO –ZnO nanocomposites were synthesized by co-precipitation method. The PXRD studies revealed that NiO, Mn2O3 and CdO possessed cubic structure, Pb2O3 possessed monoclinic structure, ZnO possessed hexagonal structure and confirmed the presence of polycrystallinity nature of NiO and Mn2O3, CdO, Pb2O3, ZnO in the nanocomposites. The average grain size of NiO nanoparticles was found to be 30.10 nm using Debye Scherer’s formula. The FESEM images of NiO nanoparticles and their nanocomposites revealed spherical shaped structure and NiO-Pb2O3 revealed needle shaped rod-like structure. EDAX analysis confirmed the composition of NiO nanoparticles and their nanocomposites. Raman spectra exhibited characteristic peaks of pure NiO and that of NiO- Mn2O3, NiO-CdO, NiO- Pb2O3, NiO-ZnO in the synthesized nanocomposites. In the PL spectra, blue and green emission was observed in the samples. UV-vis spectra revealed the absorption peaks of NiO nanoparticles and their nanocomposites. Thus, the synthesized NiO- Mn2O3, NiO-CdO, NiO - Pb2O3 and NiO-ZnO nanocomposites can be a suitable material for electrocatalysis applications. Keywords: Nickel oxide nanocomposites, Structure, Morphology, Absorption, Luminescence.

Reactive Adsorption Desulfurization of Thiophene in n-hexane over Oxides Adsorbent of NiO-ZnO/Al2O3-SiO2

2013 ◽  
Vol 455 ◽  
pp. 43-47 ◽  
Author(s):  
Xiao Ming Hou ◽  
Ben Xian Shen ◽  
Ji Gang Zhao
Keyword(s):  
Reaction Time ◽  
Structural Properties ◽  
Reaction Temperature ◽  
Chemical Process ◽  
Removal Rate ◽  
Precipitation Method ◽  
Initial Concentration ◽  
Reactive Adsorption ◽  
Adsorption Desulfurization ◽  
Co Precipitation

The oxides adsorbent of NiO-ZnO/-Al2O3-SiO2 was prepared by co-precipitation method. SEM, XRD and BET studies were performed to understand the structural properties of the adsorbent. And the adsorbent can be used for the desulfurization of thiophene in n-hexane as model gasoline. Removal rate of thiophene increased with increasing reaction time. Removal rate of thiophene in equilibrium decreases with increasing the initial concentration of thiophene. The extent of adsorption in adsorbent increased with increasing the initial concentration of thiophene. The removal rate of thiophene increases with increasing reaction temperature, it showed that the desulfurization is a chemical process not a physical process.

INFLUENCE OF SYNTHESIS CONDITIONS ON Al(OH)3–Y(OH)3/ZrB2 COMPOSITE PARTICLES

2007 ◽  
Vol 14 (06) ◽  
pp. 1135-1141 ◽  
Author(s):  
JIE-GUANG SONG ◽  
LIAN-MENG ZHANG ◽  
JUN-GUO LI ◽  
JIAN-RONG SONG
Keyword(s):  
High Temperature ◽  
Reaction Time ◽  
Precipitation Method ◽  
Composite Particles ◽  
Coating Quality ◽  
Ultrasonic Dispersion ◽  
High Temperature Properties ◽  
Synthesis Conditions ◽  
Solution Reaction ◽  
Co Precipitation

Although Zirconium diboride ( ZrB 2) is a desirable combination with some good properties, it is easily oxidized in the high-temperature air to impact high-temperature properties, which dwindles the applied range. In order to decrease oxidization and improve the high-temperature properties of ZrB 2, the surface of ZrB 2 is coated with Al ( OH )3– Y ( OH )3 to synthesize Al ( OH )3– Y ( OH )3/ ZrB 2 composite particles. In this paper, the conditions of synthesizing Al ( OH )3– Y ( OH )3/ ZrB 2 composite particles by the co-precipitation method are investigated. Al ( OH )3– Y ( OH )3/ ZrB 2 composite particles are synthesized under different conditions, but the conditions of synthesizing Al ( OH )3– Y ( OH )3/ ZrB 2 composite particles with the better coating quality require pH = 9, the appropriate concentration ( Al 3+ = 0.017 mol/L , Y 3+ = 0.01 mol/L ) of composite solution, reaction time of 60 min, titration speed of 0.05 ml/s, using the dispersant in the ZrB 2 suspension and the ultrasonic dispersion, respectively.

Synthesis and Overall Photophysical Characterization of SiO2:(Ag/SiO2) Nanostructured Sonogel Hybrid Glasses

2015 ◽  
Vol 14 (05n06) ◽  
pp. 1550016
Author(s):  
Omar G. Morales-Saavedra ◽  
Rodolfo Zanella
Keyword(s):  
Mechanical Stability ◽  
Hybrid Composites ◽  
Photophysical Properties ◽  
Optically Active ◽  
Precipitation Method ◽  
Chemical Affinity ◽  
Nlo Properties ◽  
Linear And Nonlinear ◽  
Supported Metal Nanoparticles

Bulk SiO 2-based inorganic–inorganic sonogel (SG) hybrid glasses were fabricated with Ag / SiO 2 supported metal nanoparticles (MNPs). The catalyst-free SG route was implemented to produce these optically active nanostructured composites by doping the liquid sol-phase with Ag / SiO 2 synthesized according to the deposition–precipitation method. As prepared Ag / SiO 2-MNPs exhibited particle diameters below 10 nm and homogeneous size distribution. The easy and homogeneous Ag / SiO 2 loading within the micro/mesoporous SiO 2-SG network has evidenced the guest–host chemical affinity of these systems. This fact allowed us to fabricate outstanding chemically, photo-physically and mechanically stable bulk hybrid monoliths with controllable geometry and doping rates, suitable for linear and nonlinear optical (NLO)–spectroscopic characterizations. Indeed, the hosting SG matrix provided an elevated thermal and mechanical stability protecting the reactive Ag nanoparticles from environment conditions, diminishing their tendency to from aggregates and, above all, preserving their pristine photophysical properties. Comprehensive morphological, structural, spectroscopic and NLO characterizations were performed on the obtained SiO 2:( Ag / SiO 2) hybrid composites. Results have shown that the nanocrystalline (NC) properties, multipolar nature and small sizes of the implemented Ag / SiO 2-nanoparticles, together with the bulk guest–host mechanical interactions, play a crucial role for the observation of outstanding spectroscopic and quadratic NLO properties of the developed hybrid systems.

Construction and function of a highly efficient supramolecular luminescent system

2017 ◽  
Vol 196 ◽  
pp. 219-229 ◽  
Author(s):  
Yingjie Liu ◽  
Suqian Ma ◽  
Bin Xu ◽  
Wenjing Tian
Keyword(s):  
Self Assembly ◽  
Photophysical Properties ◽  
Green Emission ◽  
Yellow Emission ◽  
Highly Efficient ◽  
System P ◽  
Low Efficiency ◽  
Assembly Behavior ◽  
And Function ◽  
Stacking Structure

Aggregation-induced emission (AIE) provides a new way of achieving highly efficient luminescent materials. In this contribution, the self-assembly behavior, molecular stacking structure and photophysical properties of two polymorphs of a supramolecular co-crystal (C1 and C2) are investigated. The block-like crystal C1, packed in segregated stacking with strong π–π interactions between the H and G molecules, shows weak green emission with a low efficiency (ΦF) of 2%. In comparison, the needle-like crystal C2, packed in segregated stacking with no obviously strong intermolecular interactions, shows bright yellow emission. More importantly, C1 exhibits mechanochromic behavior.

scholarly journals Compatible Ferroelectricity, Antiferroelectricity and Broadband Emission for a Multi-Functional 2D Organic-Inorganic Hybrid Perovskite

2021 ◽  
Author(s):  
Wenjuan Wei ◽  
Hongqiang Gao ◽  
Yuhui Tan ◽  
Yunzhi Tang
Keyword(s):  
Second Harmonic ◽  
Photophysical Properties ◽  
Blue Shift ◽  
Molecular Reorientation ◽  
Inorganic Hybrid ◽  
Electron Phonon Interaction ◽  
Broadband Emission ◽  
Hybrid Perovskite ◽  
Potential Applications ◽  
Energy Storage Efficiency

Two-dimensional (2D) organic-inorganic hybrid perovskites with multifunctional characteristics have potential applications in many fields, such as, solar cells, microlasers and light-emitting diodes (LEDs), etc. Here, a 2D organic-inorganic lead halide perovskite, [Br(CH<sub>2</sub>)<sub>3</sub>NH<sub>3</sub>]<sub>2</sub>PbBr<sub>4</sub> (<b>BPA-PbBr<sub>4</sub></b>, BPA = Br(CH<sub>2</sub>)<sub>3</sub>NH<sub>3</sub>, 3-Bromopropylamine), is examined for its photophysical properties. Interestingly, <b>BPA-PbBr<sub>4</sub></b> reveals five successive phase transitions with decreasing temperature, including successive paraelectric-ferroelectric-antiferroelectric phases. Besides, <b>BPA-PbBr<sub>4</sub></b> displays ferroelectricity and antiferroelectricity throughout a wide temperature range (<376.4 K) with accompanying saturation polrization (<i>P</i><sub>s</sub>) values of 4.35 and 2.32 μC/cm<sup>2</sup>, respectively, and energy storage efficiency of 28.2%, and also exhibits superior second harmonic generation (SHG) with maximum value accounts for 95 % of the standard KDP due to the great deformation of structure (3.2302*10<sup>-4</sup>). In addition, the photoluminescence (PL) of the <b>BPA-PbBr<sub>4</sub></b> exhibits abnormal red-shift and blue-shift in different phases due to a consequence of competition between electron-phonon interaction and the lattice expansion. Further, <b>BPA-PbBr<sub>4</sub></b> reveals a broadband emission accompanied by bright white light at room temperature (293 K), which is supposed to be due to self-trapped excitons. In short, the versatility of <b>BPA-PbBr<sub>4</sub></b> originates from molecular reorientation of dynamic organic cations, as well as significant structural distortion of PbBr<sub>6</sub> octahedra. This work paves an avenue to design new hybrid multifunctional perovskites for potential applications in the photoelectronic field.

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