Over the past 40 years, scientists have learned to synthesize colloidal nanocrystals of different composition with tunable size and shape. These features dictate the properties of these nanomaterials. Thus, their control is crucial for the discovery of phenomena, many of which contribute to technological advances. One example of the societal impact of this class of materials is the use of semiconductor nanocrystals as the active component in displays with the best color purity on the market. A second example is their use as materials platforms to advance catalyst development. Yet, the synthesis of colloidal nanocrystals still proceeds by trial and error. The search for the reaction conditions to obtain the nanocrystals with the desired composition, size and shape is time consuming and can fail in delivering the target product.

In this talk, I will highlight the importance of identifying the reaction intermediates during the formation of colloidal nanocrystals for the development of a more predictive synthesis to these nanomaterials. By discussing specific examples, I will illustrate that the chemical nature of these intermediates is diverse and that state-of-the-art in-situ techniques combined with theory are often needed to capture those transient species during the synthesis of nanocrystals. Nevertheless, I will use concrete examples to demonstrate that such efforts are worth it as the discovered mechanistic pathways pinpoint the critical steps to enhance the tunability of existing materials and to accelerate the discover of new ones.

In the same way metal complexes are converted into well-defined nanoparticles, nanoparticles can be used as tunable precursors capable of evolving into macroscopic solids with specific structural features. A consolidation step is usually required to produce the macroscopic solid from nanoparticles. The consolidation process defines the density and microstructure of the solids, which directly correlate with the electronic, thermal, and mechanical properties of the resulting material. In order to provide the material with densities as close as possible to the respective theoretical density, pressure-assisted sintering techniques are preferred, such as hot pressing or spark plasma sintering.

Characteristics of the particles such as size, shape, composition, and surface chemistry determine the sintering process and therefore dictate densification, grain growth, and materials' final microstructure. Consequently, using carefully-curated nanoparticles provides a unique opportunity to control material microstructure. In our framework, a nanoparticle is a multi-structured system consisting of an inorganic nanocrystalline domain, named the inorganic core, surrounded by surface species. Both the inorganic and surface species are tunable parameters in the design of nanoparticle-based precursors. Herein, we will employ solution-based synthesis procedures to produce precisely defined nanoparticles and explore their surface chemistry to adjust nanoparticles' reactivity during sintering to achieve a solid with specific targeted features.

Two very different approaches to controlling particles' surface chemistry need to be separated. One refers to the particle termination atoms, the other to the connected adsorbates that can be covalently bonded molecules or electrostatically adsorbed ionic groups. In this talk, we will show how surface adsorbates, intentionally or unintentionally introduced, are critical to controlling densification, grain growth, and materials' final microstructure. Furthermore, we will present different surface functionalization strategies that allow defining: atomic defects, grain boundary complexions, crystalline domain size, and the formation of secondary phase inclusions in the macroscopic solid.

Finally, we will discuss the effect of the different structural properties introduced in the macroscopic solids on their electrical and thermal transport properties and evaluate their potential as thermoelectric materials.

Photocatalytic sheets have disruptive potential in the field of solar hydrogen production from water. Recent demonstrations have shown the feasibility of their safe operation on a large scale.[1] The key challenge is the development of visible light absorbing photocatalytic particles that are efficient and stable for at least one year. In this talk, I will discuss recent efforts in our laboratory towards adapting our thin film semiconductor water splitting materials towards stable, photocatalytic particles. The methods for the synthesis of the particles and particle sheets will be highlighted, as well as the challenges for the stringent stability requirements (in water, under illumination). Proof-of-principle systems involving hydrogen evolution coupled with the oxidation of various organic molecules (so-called "value added oxidations") will be highlighted. Initial efforts with BiVO4 will be discussed, as this is a well-studied particle for the oxygen evolution reaction. Subsequently, copper oxide and antimony selenide-based systems will be discussed.

The chemistry of metal-organic and covalent organic frameworks (MOFs and COFs) is perhaps the most diverse and inclusive among the chemical sciences, and yet it can be radically expanded by blending it with nanotechnology. The result is reticular nanoscience, an area of reticular chemistry that has an immense potential in virtually any technological field.
In this talk, we explore the extension of such an interdisciplinary reach by surveying the explored and unexplored possibilities that framework nanoparticles can offer. We localize these unique nanosized reticular materials at the juncture between the molecular and the macroscopic worlds, and describe the resulting synthetic and analytical chemistry, which is fundamentally different from conventional frameworks. Such differences are mirrored in the properties that reticular nanoparticles exhibit, which we described while referring to the present state-of-the-art and future promising applications in medicine, catalysis, energy-related applications, and sensors. Finally, the bottom-up approach of reticular nanoscience, inspired by nature, is brought to its full extension by introducing the concept of augmented reticular chemistry. Its approach departs from a single-particle scale to reach higher mesoscopic and even macroscopic dimensions, where framework nanoparticles become building units themselves and the resulting super-materials approach new levels of sophistication of structures and properties.

Aliovalent I-V-VI semiconductor nanocrystals represent promising candidates for non-toxic and earth-abundant thermoelectric and infrared optoelectronic applications. Among them, famatite Cu3SbSe4 material stands out due to high absorption coefficients and narrow band gap in the mid-infrared spectral range. In this presentation we combine experiments and theory calculations to study the effects of composition and defects on optical properties of Cu3SbSe4 nanocrystals. Using fast and modular hot-injection colloidal synthesis approach, we achieve size-uniform and stoichiometric Cu3SbSe4 nanocrystals and study the influence of reaction parameters such as reaction temperature, growth time, and precursor concentrations. While a reduced activity of the Cu precursor induces the formation of Cu-deficient Cu3SbSe4 nanocrystals, an increased anion concentration or a balancing of cation precursor concentrations result in stoichiometric Cu3SbSe4 products with an absorption onset of 0.2 eV. Characterizing the products, we discover a broad solid solution for nanocrystals (nominally, CuxSbSe4, where x is 2.4–3.0), which is significantly larger than for the bulk Cu3SbSe4 phase. Within this CuxSbSe4 solid solution, the optical band gap widens to 0.35 eV as the amount of Cu decreases. Tight-binding simulations point to the existence of large amount of Cu vacancies, which are non-harmful for the optical performance of CuxSbSe4 nanocrystals. In contrast, even a small amount of CuSb and SbCu antisite defects creates intrinsic doping states, which are detrimental for Cu3SbSe4 properties. We affirm tunable band gaps by infrared spectroscopy and observe a good agreement to the theory calculations. We further report the energy-resolved photoelectric response of Cu3SbSe4 nanocrystals and show their excellent resilience towards oxidation. Our results will provide a launch platform for Cu3SbSe4 nanocrystals as one of very few non-toxic alternatives for mid-infrared applications.

Nickel boride Ni_xB_y has shown potential as an efficacious catalyst for a broad range of systems (hydrogenations, hydrogen, and oxygen evolution reactions) under challenging conditions (such as high pH or high temperatures). Preparing the nanoscale analogues of nickel borides in an attractive prospect as the increased surface area and creation of more active sites will enhance their catalytic activity. However, the nanostructure of Ni_xB_y remains underdeveloped mainly due to the notoriously difficult and energy demanging synthetic process which is not industrially compatible.^[1-3] Recent works have shown that synthetic methods at lower temperatures (<400 ºC) yield amorphous polydisperse nanocrystals (NCs), while phase purity remains an issue at higher temperatures. Here, a simple, scalable synthesis is demonstrated to obtain a phase-pure nanocrystalline Ni_xB_y. Through the solid-state reaction of either metallic Ni⁰ or NiCl₂ with NaBH₄ at a relatively low temperature (400^oC) under atmospheric pressure, crystalline nanosized Ni₂B and Ni₃B could be obtained with high yield in pure phase and with narrow size distribution (15-30 nm). Through extensive mechanistic studies, we show that Ni nanoclusters (approx. 1 nm) are intermediate in the boriding process, while the halide precursors lower the decomposition temperature of the NaBH₄ (used as a reducing agent and B source). We further explore the size control using reaction mediators, and we probe the differential nucleation and growth of Ni (clusters) or Ni_xB_y NCs while using L (amine, phosphine) and X-type (carboxylate) mediators. The synthesized Ni₃B nanopowder can undergo surface functionalization with inorganic ligands in polar solvents, forming a stable ink. Furthermore, the Ni₃B nanocrystals ink can be ligand-exchanged with organic ligands in a non-polar low-boiling point solvent. This work opens the door for the large-scale production of Ni_xB_y nanocrystals solution-processable inks to make it a commercially viable alternative catalyst to noble-metals and pave the way for other metal borides colloidal nanostructures. 

Colloidal semiconductor nanocrystals are opening new routes for a wide range of optoelectronic applications, spanning from lighting to photodetection, as their electronic properties can be tuned by changing their size and shape[1]. Core-shell nanocrystals further widen the tunability of their optoelectronic properties, due to the various energy alignments between the core and shell  [2].
In this contribution, we show how the interplay between density functional theory (DFT) simulations and various experimental techniques can provide fundamental insights into the atomistic and electronic structures of core-shell InAs@ZnSe semiconductor nanocrystals. In particular, we carry out a systematic comparison between various structural models simulated with DFT and the results of photoluminescence as well as x-ray diffraction and electron microscopy. This detailed comparison unveils information that is not available to either theory or experiment alone. We demonstrate that the composition of the core-shell structure does not switch abruptly between the core and the shell, but rather displays an In-Zn concentration gradient. Moreover, only by considering atomistic reconstructions on the surface of the nanocrystal as well as on the external core layer is it possible to obtain an electronic structure that matches the experimentally observed optical properties. Finally, we derived general insights to explain the observed boost in the photoluminescence quantum yield when the InAs particles are coated with the ZnSe shell.

Cardiovascular diseases are the leading cause of death worldwide. New treatments are continuously developed but require an in-depth understanding of cardiovascular morphology. Vascular corrosion casting provides 3D knowledge of anatomical structures by injecting a polymer resin and subsequently removing the surrounding tissue via chemical maceration, i.e. corrosion. [1] This process often leads to deformations or fragmentation of the fragile cast, resulting in a loss of information. In-situ high-resolution computed tomography (micro-CT) scans could provide detailed information on the vascular architecture without corroding the tissue. Unfortunately, distinguishing the polymer cast from the animals’ surrounding soft tissue is impossible due to a lack of CT contrast. To improve this, we introduce hafnium oxide nanocrystals (HfO₂ NCs) as contrast agents to the polymer resin. Here we communicate our insights on HfO₂ NC synthesis, their surface chemistry and their application as CT contrast agents.

We synthesize 5 – 10 nm HfO₂ NCs starting from HfCl₄.2THF in benzyl alcohol. Initially identified as a purely nonaqueous sol-gel route [2], we find the in-situ water formation to be responsible for gelation of the reaction mixture prior to particle crystallization. Through mechanistic investigation using in-situ Pair Distribution Function (PDF) analysis, Nuclear Magnetic Resonance (NMR), Extended X-ray Absorption Fine Structure (EXAFS) and rheology measurements we study this rapid precursor-to-gel conversion and subsequent crystallization. Using our new-found insight we gain better reaction control over the reaction and scale-up the synthesis, yielding gram-scale HfO₂ NCs with narrow size distribution.

To obtain a stable and homogeneous dispersion of the synthesized NCs in the casting resin, we optimized the particle’s surface chemistry. The ideal ligand is found to be a combination of a strong binding group (phosphonate), while matching the resin’s polarity via its organic tail (ethylene glycol oligomers). We demonstrate that the NCs remain stable during resin curing and homogeneously improve the contrast with concentrations as low as 5 m% of NCs.

Finally, we perform ex-vivo injections of both zebrafish and mouse models with the NC-doped resin and obtain high-quality cast visualization via segmentation of the obtained scans without having to adapt the existing injection methods. We are able to differentiate even µm scale details. This confirms the application potential of HfO₂ NCs as CT contrast agents in corrosion casting, while paving the way to obtain full cardiovascular information from casts without the need for tissue corrosion. Our results emphasize that through mechanistic insight and control over the nanocrystal synthesis, combined with an optimized surface chemistry, we can create high quality stable nanocomposites.

AECs are composed of a II^a metal (Mg, Ca, Sr) and S or Se (X), feature large bandgaps positioned in the UV and are commonly used as hosts for emissive ions. AEC nanocrystals could therefore be used as UV emitters, or scatter-free emitters based on lanthanide ions. Moreover, while most AEC crystallize in the rocksalt structure, MgX can also be grown as zinc blende crystals with lattice parameters that come close to those of commonly examined and used II^b-VI chalcogenides or III-V pnictides, such as CdSe and InP. Hence, AECs could extend the range of materials to form core/shell heterostructures out of these compounds. However, such implementations of AECs are hampered by the limited knowledge of the colloidal synthesis and the surface chemistry of these compounds. Here, we report on possible routes to synthesize these materials and the resulting surface termination of AECs by organic ligands, for which we take the formation of CaS as a starting point. We show that ~12 nm large CaS nanocubes can be formed by reacting calciumacetate and diphenylthiourea in a mixture of oleylamine (OLA), trioctylamine and oleic acid (OA)[1]. Using Nuclear Magnetic Resonance (NMR) and infrared (IR) spectroscopy, we demonstrate that such as-synthesized CaS nanocubes are terminated by a dense shell of oleate ligands, which are unequally packed at the surface, and small traces of OLA. Addition of a carboxylic acid shows the dynamic behavior of this dense shell and induces a slow reorganization of the ligands by breaking up the dense packing and replacing hydroxides at the surface by oleates. Apart from providing detailed insight in the surface chemistry of CaS NCs, this work shows that known approaches and concepts to analyze and rationalize the interaction between colloidal nanocrystals and surface-active ligands can be extended to AEC nanocrystals.

The pulmonary administration of nanomedicines such as viral vaccines is a promising delivery route because it is direct, noninvasive, and it can be used for both systemic delivery and lung targeting. However, the same mechanisms that protect us from pathogens entering via the inhalation route lead to the rapid elimination or degradation of nanomedicines. Most nanomedicines designed for pulmonary administration do not reach clinical practice and this is reflected in the low number of newly approved inhalation drugs.[1] This reality contrasts with the increase in lung diseases due to global ageing and new infectious diseases.[2] Since one of the advantages of pulmonary administration is the direct targeting of the lung, the challenges of improving this route of administration are worthy of being addressed towards overcoming unmet clinical needs. In this context, we will demonstrate that it will be key to study and understand the nano-bio interaction with lung barriers to design better drug nanovectors. To this end, we will give examples of how multifunctional nanoparticles capable of encapsulating drugs and being labeled with contrast agents to perform multiscale studies will be an essential tool to characterize these interactions.[3] We will provide examples of how different coating agents determine lung retention time, clearance by alveolar macrophages, penetration into the lung, etc. Finally, we will show how this may impact the therapeutic efficiency of some of these nanomedicines.

Colloidal lead halide perovskite (LHP) nanocrystals (NCs), with bright and spectrally narrow photoluminescence (PL) tunable over the entire visible spectral range, are of immense interest as classical and quantum light sources. Severe challenges LHP NCs form by sub-second fast and hence hard-to-control ionic metathesis reactions, which severely limits the access to size-uniform and shape-regular NCs in the sub-10 nm range. We show that a synthesis path comprising an intricate equilibrium between the precursor (TOPO-PbBr₂ complex) and the [PbBr₃^-] solute for the NC nucleation may circumvent this challenge [1]. This results in a scalable, room-temperature synthesis of monodisperse and isolable CsPbBr₃ NCs, size-tunable in the 3-13 nm range. The kinetics of both nucleation and therefrom temporally separated growth are drastically slowed, resulting in total reaction times of up to 30 minutes. The methodology is then extended to FAPbBr₃ (FA = formamidinium) and MAPbBr₃ (MA = methylammonium), allowing for thorough experimental comparison and modeling of their physical properties under intermediate quantum confinement. In particular, NCs of all these compositions exhibit up to four excitonic transitions in their linear absorption spectra, and we demonstrate that the size-dependent confinement energy for all transitions is independent of the A-site cation.  We then show that this synthesis – relying on the labile ligand capping with TOPO-phosphinic acid mixture – makes for a convenient platform for the subsequent surface functionalization with diverse capping ligands [2]. Robust surface functionalization of highly ionic surfaces, as is the case of LHP NCs, has remained a formidable challenge due to the inherently non-covalent weak surface bonding. Leveraging the vast and facile molecular engineering of phospholipids, we present their efficacy as surface capping ligands for LHP NCs. Molecular dynamics simulations and solid-state NMR confirm that the surface affinity of these zwitterionic molecules is primarily governed by the geometric fitness of their anionic and cationic moieties. Judicious selection of the ligands yielded colloidally robust FAPbBr₃ and MAPbBr₃ NCs and enabled colloids in a variety of solvents, from n-hexane to acetone. Robustness of the surface capping is also reflected in optical properties: NCs exhibit PL quantum yield (QY) above 96% after numerous purifications. NCs are essentially blinking-free at a single particle level.

We will discuss the atomistic details of the ligand surface binding, ranging from conventional alkylammonium ligands [3] to diverse zwitterionic moeities. In particular, we show that solution and solid-state NMR readily captures the surface binding motifs and the impact of the ligands on the surface structure of CsPbBr₃ NCs [4].

Q. Akkerman et al. Science 2022, 377, 1406-​1412

V. Morad et al. submitted

A. Stelmakh et al. Chem. Mater. 2021, 33, 5962−5973

M. Aebli et al. submitted

Colloidal synthesis routes allow precise control over material parameters at the nanometer scale with moderate capital or operating costs and with high-throughput production and material yields. Stimulated by its simplicity and huge potential, countless groups all around the world have developed an extensive library of synthetic strategies and routes to produce nanocrystals with almost any composition, size, and shape. However, for such control over material parameters at the nanoscale to truly impact real applications, colloidal nanocrystals need to be arranged into functional patterns, thin films, porous nanomaterials, or highly dense nanocomposites, depending on the application. Additive manufacturing technologies based on layer-by-layer deposition of material ejected from a nozzle in the form of an ink are well-suited to produce macroscopic structures from colloids but are limited in terms of printing speed and resolution. Electrohydrodynamic (EHD) jetting uniquely allows the generation of submicrometer jets that can reach speeds above 1 m s^-1, but such jets cannot be precisely collected by too slow mechanical stages. In this talk, I will present our progress in the control of the jet trajectory in EHD jetting technologies through a voltage applied to electrodes located around the jet. This method allows to continuous adjust the jet trajectory with lateral accelerations up to 10⁶ m s^-2. Through electrostatically deflecting the jet, 3D objects with submicrometer features can be printed by stacking material layers on top of each other at layer-by-layer frequencies as high as 2000 Hz. The fast jet speed and large layer-by-layer frequencies achieved translate into printing speed up to 0.5 m s^-1 in-plane and 0.4 mm s^-1 in the vertical direction, three to four orders of magnitude faster than techniques providing equivalent feature sizes. This technique is applied to the production of electrode materials for energy conversion and storage.

Epitaxial growth methods usually need dedicated equipment, high energy consumption to maintain pure vacuum conditions and evaporation of source materials, and elevated substrate temperatures. Solution epitaxial growth requires nothing of that but is rarely used because the achieved microstructures are of low quality, not homogeneous, and finally exhibit worse performances in devices. We have introduced several growth methods including ink-jet printing [1], drop-casting [2] or antisolvent-vapor-assisted-crystallization [3] to obtain epitaxial perovskite micro-crystallites whose shapes and sizes can be controlled by the synthetic conditions. These micro-crystallites are not only oriented on the substrates such as mica or PbS single crystals, but also exhibit smooth side walls, which coincide with crystalline facets. Thus, they are acting as optical micro-resonators, supporting lasing under optical excitation. The obtained threshold powers as well as the environmental stability are competitive to those obtained by vapor deposition methods. The solution epitaxial growth can also be performed to obtain closed epitaxial films, instead of arrays of ordered micro-crystals, representing a common goal for epitaxial growth. Thus, solution epitaxy applied to metal-halide perovskites and performed in almost ambient conditions is rivaling with vapor deposition methods, even though it is achieved by cost-effective and simple methods and on cheap and commercially available substrates.

III-V quantum dots are printable semiconductors free of hazardous substances. In this talk, recent progress in III-V QDs synthesis at Ghent University and the device implementation of these materials is discussed. First, we show that the formation of InP-based QDs with near-unity photoluminescence quantum yield across the visible spectrum is now possible. This result is achieved by implementing a core/shell/shell structure, in which the composition of the inner shell is gradually changed from Se-rich to S-rich Zn(Se,S) with decreasing core QD size. We demonstrate that such application grade QDs can be used as color convertors to make on-chip QD-LEDs with +50% colo conversion efficiency. Second, we discuss how rational adaptations to the synthesis of In(As,P) QDs result in one-batch-one-size protocols yielding In(As,P) QD batches with a band-edge absorption up to 1600 nm, and we demonstrate the formation of QD photodiodes sensitive up to 1400 nm from these QDs. Both examples highlight how III-V QDs are evolving from a material for lab-scale proof-of-principle to devices ready of the consumer-market

Operando characterization techniques are indispensable for understanding the catalysts evolution during operation. Electrochemical liquid-phase transmission electron microscopy (ec-LPTEM) grants the capability of real-time imaging of electrochemically-induced processes in liquid media. Herein, we describe the advancements of ec-LPTEM towards studying the solid-liquid-gas interfacial processes occurring on Co-based oxide oxygen evolving catalysts. By performing real-time measurements, we can associate the potential-dependent variation of the local contrast to the effects that precede the electrocatalytic reaction such as electrowetting and redox-induced reactions. Further, through optimization of the microcell, we report on the direct probing of the evolution of molecular oxygen by operando electron energy loss spectroscopy (EELS). Similar experiments on IrO2 particles indicate the capability to separate the contribution of different components in the EEL spectra, providing qualitative maps of O2 and liquid electrolyte. Our work on catalytic particles exemplifies the crucial role that surface sensitive and electrochemical microcell TEM techniques can play in detailing the mechanism of electrocatalytic processes and can provide a new characterization framework aiding development of novel design routes for targeted nanocatalyst preparation.

Lead halide perovskites successfully advance towards applications in solar cells, light-emitting devices, and high-energy radiation detectors. Recent progress in understanding their uniqueness highlights the role of optoelectronic tolerance to intrinsic defects, particularly long diffusion lengths of carriers, and highly dynamic 3d inorganic framework. This picture indicates that finding an analogous material among non-group-14 metal halides can be very challenging, if possible at all. On the other hand, a judicious choice of chemistry made it possible to noticeably increase the performance of formamidinium tin iodide perovskites when integrated into thin-film photovoltaic devices. The main challenge with this material originates from the easiness of the trap states generation, which are typically ascribed to the oxidation of Sn(II) to Sn(IV). In this work, we describe the synthesis of colloidal monodisperse FASnI₃ NCs, whereby thorough control of the purity and redox chemistry of the precursors allows the concentration of Sn(IV) to be reduced to an insignificant level, to probe the intrinsic structural and optical properties of these NCs. Intrinsic FASnI₃ NCs exhibit unusually low absorption coefficients of 4•10³ cm^-1 at the first excitonic transition, a 190 meV increase of the bandgap as compared to the bulk material, and a lack of excitonic resonances. These features are attributed to a highly disordered lattice, distinct from the bulk FASnI₃ as supported by structural characterizations and first-principles calculations.

Self-assembly of colloidal nanocrystals into long-range-ordered structures through a bottom-up approach is highly promising for creating metamaterials with programmable functionalities arising from various synergistic effects and emergent interactions between neighboring NCs. Both single-component and binary superlattices reported so far were mainly composed of spherical NCs limiting the variety of obtained structures to the ones isostructural with the known atomic lattices [1]. A far greater structural diversity is accessible via assembling NCs of different shapes, e.g. nanoplates, nanorods, nanocubes, or nanodiscs. Notably, lead halide perovskite nanocrystals are characterized by remarkable optical properties together with being synthetically available in the monodisperse form making them attractive candidates as building blocks for self-assembly. A new step toward unique positional and orientational order would be to combine perovskite NCs with dielectric NCs of anisotropic shape. To this end, we have chosen LaF₃ and NaGdF₄ NCs as a second component for SLs due to their synthetic accessibility and well-defined, ensemble-uniform morphology.

Co-assembly of cesium lead halide nanocubes with disc-shaped LaF₃ NCs (9.2-28.4 nm in diameter) leads to the formation of six columnar structures with AB, AB₂, AB₄, and AB₆ stoichiometry as well as to noncolumnar lamellar and ReO₃-type SLs by employing larger perovskite NCs [2]. The latter two SLs proved to exhibit characteristic features of the collective ultrafast emission – superfluorescence. Intending to broaden the variety of building blocks for NC SLs, we utilized organic-inorganic perovskite NCs, namely FAPbBr₃ NCs, for the formation of binary SLs with spherical NaGdF₄ NCs (b-ABO₃-, AlB₂-, AB₂-, NaCl-type structures) and LaF₃ nanodiscs (columnar AB-type and lamellar SLs). Combining larger and thicker NaGdF₄ nanodiscs (18.5 nm in thickness) with cesium lead halide NCs resulted in the CaC₂-like and AB₃-type SLs. For CaC₂- and ABO₃-type structures, we expanded the scope of the available dimensionalities of SLs by employing microemulsion-templated self-assembly which allowed for the formation of three-dimensional binary supraparticles [3].