Synthesis conditions influencing formation of MAPbBr3 perovskite nanoparticles prepared by the ligand-assisted precipitation method

Abstract This work reports on an optimized procedure to synthesize methylammonium bromide perovskite nanoparticles. The ligand-assisted precipitation synthetic pathway for preparing nanoparticles is a cost-effective and promising method due to its ease of scalability, affordable equipment requirements and convenient operational temperatures. Nevertheless, there are several parameters that influence the resulting optical properties of the final nanomaterials. Here, the influence of the choice of solvent system, capping agents, temperature during precipitation and ratios of precursor chemicals is described, among other factors. Moreover, the colloidal stability and stability of the precursor solution is studied. All of the above-mentioned parameters were observed to strongly affect the resulting optical properties of the colloidal solutions. Various solvents, dispersion media, and selection of capping agents affected the formation of the perovskite structure, and thus qualitative and quantitative optimization of the synthetic procedure conditions resulted in nanoparticles of different dimensions and optical properties. The emission maxima of the nanoparticles were in the 508–519 nm range due to quantum confinement, as confirmed by transmission electron microscopy. This detailed study allows the selection of the best optimal conditions when using the ligand-assisted precipitation method as a powerful tool to fine-tune nanostructured perovskite features targeted for specific applications.

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Synthesis of luminescent nanoparticle embedded polymer nanocomposites for scintillation applications

MRS Proceedings ◽

10.1557/opl.2011.123 ◽

2011 ◽

Vol 1312 ◽

Cited By ~ 5

Author(s):

Thomas Rogers ◽

Chenlu Han ◽

Brent Wagner ◽

Jason Nadler ◽

Zhitao Kang

Keyword(s):

Polymer Matrix ◽

Gamma Ray ◽

Cost Effective ◽

Chemical Precipitation ◽

Precipitation Method ◽

Colloidal Solutions ◽

Index Matching ◽

Luminescent Nanoparticle ◽

Matrix Nanocomposite ◽

Selection Of

ABSTRACTDetecting gamma-ray emission from radionuclides hidden within containers is a significant concern to national security and can be accomplished with scintillating materials such as NaI:Tl, LaBr3:Ce crystals. However, the use of these high quality crystals limits the functionality of the detectors due to their high cost and scalability issues. Therefore the development of more durable, more easily manufactured, and more cost effective scintillating materials is desired. The incorporation of nanophosphors or Quantum Dots (QDs) into a polymer matrix to produce a transparent nanocomposite could potentially provide an alternative method to fabricate scintillating detectors. Embedded in a suitable polymer matrix, nanocomposite detectors may be easily made suitably large for portal monitors. Also, preparation of suitable particle sizes and/or compositions permits selection of a photon wavelength that optimally matches the photodetector response curve to increase the number of photons collected per pulse. In this paper a series of LaF3:Ce nanophosphors with varying doping concentrations (1–30mol%Ce) were synthesized using a chemical precipitation method. Photoluminescence and photoluminescence excitation characterizations indicated that the highest luminescent intensity was obtained from the 20%Ce doped sample with a peak emission at 325 nm. The refractive indices of the nanoparticles were identified by index matching measurements. Then an index matched epoxy was selected for incorporation of these nanoparticles to prepare transparent nanocomposite scintillators. In addition, colloidal solutions of CdTe QDs with various emitting colors were synthesized and incorporated into a Polymethyl-methacrylate (PMMA) matrix to make transparent nanocomposites. An initial evaluation of the scintillation behavior of these nanocomposites was evaluated by exposure to gamma rays.

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On the Reaction Pathways and Growth Mechanisms of LiNbO3 Nanocrystals from the Non-Aqueous Solvothermal Alkoxide Route

Nanomaterials ◽

10.3390/nano11010154 ◽

2021 ◽

Vol 11 (1) ◽

pp. 154

Author(s):

Mathias Urbain ◽

Florian Riporto ◽

Sandrine Beauquis ◽

Virginie Monnier ◽

Jean-Christophe Marty ◽

...

Keyword(s):

Colloidal Stability ◽

Formation Rate ◽

Reaction Medium ◽

Precursor Solution ◽

Medium Composition ◽

Shape Anisotropy ◽

Reaction Pathways ◽

Growth Mechanisms ◽

Shape Distribution ◽

Size And Shape

Phase-pure, highly crystalline sub-50 nm LiNbO3 nanocrystals were prepared from a non-aqueous solvothermal process for 72 h at 230 °C and a commercial precursor solution of mixed lithium niobium ethoxide in its parent alcohol. A systematic variation of the reaction medium composition with the addition of different amounts of co-solvent including butanol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol resulted in the formation of nanocrystals of adjustable mean size and shape anisotropy, as demonstrated from XRD measurements and TEM imaging. Colloidal stability of ethanol- and water-based suspensions was evaluated from dynamic light scattering (DLS)/zeta potential studies and correlated with FTIR data. Thanks to the evolution in the nanocrystal size and shape distribution we observed, as well as to the available literature on the alkoxide chemistry, the reaction pathways and growth mechanisms were finally discussed with a special attention on the monomer formation rate, leading to the nucleation step. The polar, non-perovskite crystalline structure of LiNbO3 was also evidenced to play a major role in the nanocrystal shape anisotropy.

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Accelerating the optimization of enzyme-catalyzed synthesis conditions via machine learning and reactivity descriptors

Organic & Biomolecular Chemistry ◽

10.1039/d1ob01066b ◽

2021 ◽

Author(s):

Zhongyu Wan ◽

Quan-De Wang ◽

Dongchang Liu ◽

Jinhu Liang

Keyword(s):

Machine Learning ◽

Optimal Synthesis ◽

Human Knowledge ◽

Crucial Importance ◽

Reactivity Descriptors ◽

Synthesis Conditions ◽

Wide Range ◽

Synthesis Reactions ◽

Selection Of

Enzyme-catalyzed synthesis reactions are of crucial importance for a wide range of applications. An accurate and rapid selection of optimal synthesis conditions is crucial and challenging for both human knowledge...

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