PbS Nanocrystals Made Using Excess Lead Chloride Have a Halide-Perovskite-Like Surface

Green, Philippe B.; Villanueva, Francisco Yarur; Demmans, Karl Z.; Imperiale, Christian J.; Hasham, Minhal; Nikbin, Ehsan; Burns, Darcy C.; Wilson, Mark W.

doi:10.1021/acs.chemmater.1c02962

Cited by 13 publications

(29 citation statements)

References 104 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The patchy particles contain one bead for the NC core and one bead for each of the eight ligand “patches” with the ligand bead center on the surface of the core. This is consistent with facet-specific binding of ligands to the (111) NC and (100) NC facets, with denser ligand coverage on the (111) NC facets. ,− For patchy particle representations of small NC core sizes, the dense (111) NC ligand patches completely mask the NC core and smear out the effect of facet-specific ligand binding. This likeness reduces the number of simulation elements from ∼10000 to 9.…”

Section: Resultssupporting

confidence: 63%

Prediction of PbS Nanocrystal Superlattice Structure with Large-Scale Patchy Particle Simulations

2022

View full text Add to dashboard Cite

Predictive control over the assembly of nanocrystals (NCs) into ordered, oriented superlattices (SLs) and a comprehensive theoretical framework consistent with experimental tuning parameters can be challenging to establish due to the subtle influence of many competing thermodynamic driving forces at molecular length scales. For ∼4–8 nm diameter PbS NCs in particular, orientationally ordered SLs typically crystallize along the Bain path from a body-centered cubic (BCC) to a face-centered cubic (FCC) pathway through body-centered tetragonal (BCT) intermediates, depending on characteristics of the surface-capping ligands: ligand coverage, free ligand fraction, and ligand-shell solvation. Here, we parameterize a patchy particle representation of PbS NCs for large-scale Brownian dynamics (BD) simulations. Key parameters defining the strength of attractive and repulsive forces are determined by comparison of the simulated solution structure to that measured by small-angle neutron scattering (SANS) for oleate-capped PbS NCs. The patchy particle self-assembly behavior is subsequently probed by using a sedimentation equilibrium methodology, which returns a complete equation of state with a single simulation and allows extraction of the SL parameters and NC orientations. We find that the interaction energies determined by using solution SANS are capable of parameterizing simulations that exactly match grazing-incidence small-angle X-ray scattering (GISAXS) measurements of experimentally realized PbS NC superlattices. As the size of an effective isotropic repulsive ligand core increases, the lattice transitions predictably along the uniaxial expansion pathway BCC → BCT → FCC with unit cell axes lengths that match experimental measurements. Weak attractions between (111)NC ligand patches, consistent with anisotropic ligand coverage on lead chalcogenide NCs, stabilize NC orientations in the SL. The nearest-neighbor spacing corresponds well with the repulsive core size. We map the phase diagram across typical NC core diameters and ligand lengths and present a predictive framework that agrees with the observed SLs. This study elucidates the salient features of PbS NC interactions stabilizing experimentally observed SLs and highlights the predictive power of patchy particle representations when benchmarked by complementary experimental data.

show abstract

Section: Resultssupporting

confidence: 63%

Prediction of PbS Nanocrystal Superlattice Structure with Large-Scale Patchy Particle Simulations

2022

View full text Add to dashboard Cite

show abstract

“…Interestingly, Pb3S2Cl2 is the first reported chalcohalide where Clis coordinated by an octahedron of Pb 2+ ions. Such coordination has been recently proposed on the surface of PbS NCs synthesized in excess of PbCl2 to account for the formation of a Cl-rich shell that improves the optical properties, [40][41][42][43] suggesting that these NCs might be passivated by a layer of some lead sulfochloride compound. For further comparisons between the structures of Pb3S2Cl2 and Pb3S2X2 compounds see section S4 of the SI, which includes the structure refinements of Pb4S3Br2 and Pb4S3I2 NCs and a comparison of PDF profiles by RootProf.…”

Section: Resultsmentioning

confidence: 90%

“…This supports the recent observations of a PbClx-rich shell on the surface of PbS NCs synthesized using PbCl2 as a precursor, a condition that is remarkably similar to our synthetic protocol and might indeed lead to the formation of a lead sulfochloride surface layer. [40][41][42][43] We remark that our use of perovskite NCs as disposable and phase-selective epitaxial templates parallels that of reaction-directing groups in traditional organic chemistry and catalysis, 27 and allowed us to design the phase-selective synthesis of two yet unknown materials (Pb3S2Cl2 and Pb4S3Cl2) based on structural considerations only. Such an approach to a deterministic synthesis of NCs could be extended to other phases with known or predictable epitaxial relations, taking advantage of the vast library of already reported nanomaterials as starting templates.…”

Section: Discussionmentioning

confidence: 95%

Halide Perovskites as Disposable Epitaxial Templates for the Phase-Selective Synthesis of Lead Sulfochloride Nanocrystals

Toso

Imran

Mugnaioli

et al. 2022

Preprint

View full text Add to dashboard Cite

Colloidal chemistry grants access to a wealth of materials through simple and mild reactions. However, even few elements can combine in a variety of stoichiometries and structures, potentially resulting in impurities or even wrong products. Similar issues have been long addressed in organic chemistry by using reaction-directing groups, that are added to a substrate to promote a specific product and are later removed. Inspired by such approach, we demonstrate the use of CsPbCl3 perovskite nanocrystals to drive the phase-selective synthesis of two novel lead sulfochlorides: Pb3S2Cl2 and Pb4S3Cl2. When homogeneously nucleated in solution, lead sulfochlorides form Pb3S2Cl2 nanocrystals. Conversely, the presence of CsPbCl3 triggers the formation of Pb4S3Cl2/CsPbCl3 epitaxial heterostructures. The phase selectivity is guaranteed by the continuity of the cationic subnetwork across the interface, a condition not met in a hypothetical Pb3S2Cl2/CsPbCl3 heterostructure. The perovskite domain is then etched, delivering phase-pure Pb4S3Cl2 nanocrystals that could not be synthesized directly.

show abstract

“…For example, observing ionic groups intercalating between organic molecules is complicated. , If the surface is not analyzed with the right tools, there is a considerable risk of overlooking certain species, leading to an incorrect interpretation of the observed phenomena. This represents a challenge, and careful considerations need to be made to trace all possible elements that may end up on the particle surface by considering both the precursors used for the NP synthesis and the surface treatments used …”

Section: The Challengesmentioning

confidence: 99%

Solution-Processed Inorganic Thermoelectric Materials: Opportunities and Challenges

et al. 2022

View full text Add to dashboard Cite

Thermoelectric technology requires synthesizing complex materials where not only the crystal structure but also other structural features such as defects, grain size and orientation, and interfaces must be controlled. To date, conventional solid-state techniques are unable to provide this level of control. Herein, we present a synthetic approach in which dense inorganic thermoelectric materials are produced by the consolidation of well-defined nanoparticle powders. The idea is that controlling the characteristics of the powder allows the chemical transformations that take place during consolidation to be guided, ultimately yielding inorganic solids with targeted features. Different from conventional methods, syntheses in solution can produce particles with unprecedented control over their size, shape, crystal structure, composition, and surface chemistry. However, to date, most works have focused only on the low-cost benefits of this strategy. In this perspective, we first cover the opportunities that solution processing of the powder offers, emphasizing the potential structural features that can be controlled by precisely engineering the inorganic core of the particle, the surface, and the organization of the particles before consolidation. We then discuss the challenges of this synthetic approach and more practical matters related to solution processing. Finally, we suggest some good practices for adequate knowledge transfer and improving reproducibility among different laboratories.

show abstract

PbS Nanocrystals Made Using Excess Lead Chloride Have a Halide-Perovskite-Like Surface

Cited by 13 publications

References 104 publications

Prediction of PbS Nanocrystal Superlattice Structure with Large-Scale Patchy Particle Simulations

Prediction of PbS Nanocrystal Superlattice Structure with Large-Scale Patchy Particle Simulations

Halide Perovskites as Disposable Epitaxial Templates for the Phase-Selective Synthesis of Lead Sulfochloride Nanocrystals

Solution-Processed Inorganic Thermoelectric Materials: Opportunities and Challenges

Contact Info

Product

Resources

About