Saturation Of Bonds Research Articles

Visualizing defect dynamics by assembling the colloidal graphene lattice

Graphene has been under intense scientific interest because of its remarkable optical, mechanical and electronic properties. Its honeycomb structure makes it an archetypical two-dimensional material exhibiting a photonic and phononic band gap with topologically protected states. Here, we assemble colloidal graphene, the analogue of atomic graphene using pseudo-trivalent patchy particles, allowing particle-scale insight into crystal growth and defect dynamics. We directly observe the formation and healing of common defects, like grain boundaries and vacancies using confocal microscopy. We identify a pentagonal defect motif that is kinetically favoured in the early stages of growth, and acts as seed for more extended defects in the later stages. We determine the conformational energy of the crystal from the bond saturation and bond angle distortions, and follow its evolution through the energy landscape upon defect rearrangement and healing. These direct observations reveal that the origins of the most common defects lie in the early stages of graphene assembly, where pentagons are kinetically favoured over the equilibrium hexagons of the honeycomb lattice, subsequently stabilized during further growth. Our results open the door to the assembly of complex 2D colloidal materials and investigation of their dynamical, mechanical and optical properties.

Disilane-bridged architectures: an emerging class of molecular materials.

Disilanes are organosilicon compounds that contain saturated Si-Si bonds. The structural characteristics of Si-Si single bonds resemble those of C-C single bonds, but their electronic structure is more similar to that of C[double bond, length as m-dash]C double bonds, as Si-Si bonds have a higher HOMO energy level. These organosilicon compounds feature unique intramolecular σ electron delocalization, low ionization potentials, polarizable electronic structure, and σ-π interaction. It has been demonstrated that the employment of disilane units (Si-Si) is a versatile and effective approach for finely adjusting the photophysical properties of organic materials in both solution and solid states. In this review, we present and discuss the structure, properties, and relationships of novel σ-π-conjugated hybrid architectures with saturated Si-Si σ bonds. The application of disilane-bridged σ-conjugated compounds as optoelectronic materials, multifunctional solid-state emitters, CPL, and non-linear optical and stimuli-responsive materials is also reviewed.

Study of adipose tissue of Kemerovo piglets: Detection of beige adipocytes

Animals have two types of adipose tissue differing in structure and function: white (WAT) and brown (BAT). Beige adipose tissue (BeAT) is a result of WAT browning, when beige adipocytes appear between white adipocytes in response to exposure to cold, diet or physical activity. BeAT shares morphological and biochemical characteristics with BAT, is thermogenic and dissipates energy in the form of heat, unlike WAT, which is responsible for energy storage. Pigs do not have classic BAT, and modern breeds are sensitive to cold. There is literature information that BeAT has been found in cold-resistant pigs. The aim of the work was to study adipose tissue of piglets of the Kemerovo cold-resistant breed under growing conditions in the cold season and to identify the localization of BeAT. Histological studies have shown two types of adipocytes in subcutaneous fat samples (lateral, backfat and axillary): white, with one large fat droplet, and beige, multilocular. Larger cells were detected in backfat fat (69.36±12.98 µm) compared with lateral (53.25±9.27 µm) and axillary fat (45.94±8.29 µm). Only WAT with a diameter of 35.69±6.96 µm was present in the internal perirenal fat. Raman spectroscopy was used to evaluate the overall fatty acid profile of the tested samples. The main peaks were noted in all samples: 970 cm-1 (=C-H out-of-plane bend), 1266/1272 cm-1 (=C-H symmetrical rock) and 1655 cm-1 (C=C stretching) responsible for unsaturated bonds, and signals at 1297/1301 cm-1 (CH2 twisting), 1430/1460 cm-1 (CH2 symmetrical deformation (scissoring)) and 1735/1746 cm-1 (C=O stretching) corresponding to saturated bonds or ester groups. Internal perirenal fat contained the largest number of saturated fatty acid bonds, subcutaneous axillary fat — the smallest. The average intensity of the peaks was 0.4801010 and 0.639995, respectively. According to the results of gas chromatography, the largest amount of polyunsaturated fatty acids was noted in the subcutaneous fat samples: 20.199 in backfat fat, 21.749 in lateral and 20.436 in axillary fat compared to 18.636 in internal fat. Activation of beige cells in Kemerovo pigs under cold exposure, according to the authors, plays a crucial role in the heat balance, allowing them to tolerate cold without severe shivering. The study of the BeAT formation is of great practical importance for changing energy metabolism and increasing thermogenesis in newborn piglets by genome editing, as well as for improving the quality of pig’s fat.

Catalytic Mechanisms of Transfer Hydrogenation of Azobenzene with Ammonia Borane by Pincer Bismuth Complex: Crucial Role of C=N Functional Group on the Pincer Ligand.

Transfer hydrogenation of azobenzene with ammonia borane mediated by pincer bismuth complex 1 was systematically investigated through density functional theory calculations. An unusual metal-ligand cooperation mechanism was disclosed, in which the saturation/regeneration of the C=N functional group on the pincer ligand plays an essential role. The reaction is initiated by the hydrogenation of the C=N bond (saturation) with ammonia borane to afford 3CN , which is the rate-determining step with Gibbs energy barrier (ΔG≠ ) and Gibbs reaction energy (ΔG) of 25.6 and -7.3 kcal/mol, respectively. 3CN is then converted to a Bi-H intermediate through a water-bridged pathway, which is followed up with the transfer hydrogenation of azobenzene to produce the final product N,N'-diphenylhydrazine and regenerate the catalyst. Finally, the catalyst could be improved by substituting the phenyl group for the tert-butyl group on the pincer ligand, where the ΔG≠ value (rate-determining step) decreases to 24.0 kcal/mol.

Partial Hydrogenation of FAME on Trickle Bed Reactor using Nickel Catalyst

FAME (fatty acid methyl ester) is an alternative fuel that is still limited in its application to engines because its low oxidation stability affects the quality of biodiesel storage. A solution to overcome this problem is the partial hydrogenation process in which polyunsaturated FAMEs react with hydrogen, and a catalyst breaks down unsaturated bonds which are oxidation determinants. The use of Ni/Al2O3 catalyst is more advantageous due to its lower cost and higher activity. In this research, partial hydrogenation was carried out in a trickle-bed reactor. The objective of the research is to investigate the effect of operating conditions on FAME conversion. The experimental result shows that the partial hydrogenation of polyunsaturated FAMEs in a trickle bed reactor broke down the polyunsaturated bonds (C19:2) of FAME’s into monounsaturated bonds (C19:1) and saturated bonds (C19:0). The conversion of polyunsaturated FAMEs reaches 8.93% under the inlet pressure of 0.7 MPa, the inlet temperature of 160°C, the hydrogen flowrate of 250 ml/min, the biodiesel flowrate of 0.667 ml/min, and the catalyst size of 1.5 mm.

Improved solubility and hygroscopicity of enoxacin by pharmaceutical salts formation with hydroxybenzonic acids via charge assisted hydrogen bond

With our ongoing purpose to improve the solubility of enoxacin (EX) and avoid its hygroscopicity by forming pharmaceutical salts, three unreported pharmaceutical salts of EX with m-hydroxybenzoic acid ((HEX)·C7H5O3·H2O, EX-MHBA) (1), protocatechuic acid ((HEX)·C7H5O4·2H2O, EX-PCA) (2) and gallic acid ((HEX)·C7H5O5, EX-GLA) (3) have been designed and synthesized by using solution evaporation approach and the description of their structures has been provided. Crystal structure and theoretical calculation analysis show that all three pharmaceutical salts undergo proton transfer and held stable crystal structure via charge assisted hydrogen bond. The solubility analysis of EX-MHBA, EX-PCA and EX-GLA showed that their solubilities were significantly higher than those of pure EX. The reason may be that both EX and the three hydroxybenzoic acids depend on charge assisted hydrogen bond to form EX-MHBA, EX-PCA and EX-GLA pharmaceutical salts, which increase the solubility of EX by ionizing it from the neutral molecule to the ionic state. Meanwhile, the hygroscopicity of EX-MHBA, EX-PCA and EX-GLA pharmaceutical salts was markedly improved compared to pure EX. This may be due to the near saturation of hydrogen bonds between the carboxylic acid group of hydroxybenzoic acid and its neighboring groups, resulting in the carboxylic acid group of hydroxybenzoic acid may have difficulty binding to external water molecules. The success of this work suggests that it may provide an encouraging approach to improve the solubility of insoluble active pharmaceutical ingredients while avoiding their hygroscopicity. Further to this, it is surprising that the antibacterial activities in vitro of three pharmaceutical salts of EX are better than that of the EX.

Lattice Expansion and Electronic Reconfiguration of MnCu Oxide Catalysts for Enhanced Transfer Hydrogenation of Levulinate

Lattice-strained metal oxides often display enhanced catalytic activity and selectivity on activation of C–H, C═C, C═O, and O–H bonds in bio-oxygenates. However, limited experimental studies have been conducted on the structure sensitivity for tandem reactions, particularly on complicated surface redox chemical chain reactions over strained oxide materials. In this work, we employed transfer hydrogenation of levulinate as a representative example to illustrate how lattice strain affects tandem oxidation (dehydrogenation, C–H/O–H bond cleavage) and reduction (hydrogenation, C═O bond saturation) reactions. The key finding is that lattice strain at MnOx–CuOx boundaries within bimetallic MnCu oxides leads to a highly unsymmetrical strain across the interface and lattice distortion. Such unique behaviors further induce the Jahn–Teller effect for electronic reconfiguration and field split for Mn 3d orbitals. Thus, tandem H2 generation and hydrogenation of levulinate to valerolactone can occur much more efficiently with a fivefold enhancement over monometallic oxide catalysts. Detailed characterization of fresh and sintered catalyst samples further demonstrated the critical role of expansion of the Mn–O facet and phase segregation in facilitated chemical chain reactions. The design principles discussed in this work could be potentially applied for other non-noble oxide catalysts in energy and environmental fields.

Catalytic hydrocracking of inedible palm stearin for the production of drop-in aviation fuel and comparison with other inedible oils

This work describes the use of palm stearin oil as a feed for the catalytic hydrocracking to produce the renewable aviation kerosene and diesel using the hydrocracking catalyst in a continuous flow fixed bed reactor. The efficacy of this method is evaluated using several reaction parameters, including hydrocracking temperature, hydrogen pressure, liquid hourly space velocity (LHSV), hydrogen to feed ratio (H2/feed) and time on stream (TOS). Higher temperatures and lower LHSVs are dominant to produce kerosene with maximum selectivity of 55.7%, while lower temperatures and LHSVs favoured the diesel production with maximum of 75.4% selectivity. The isomerization reactions were promoted by higher hydrocracking temperature due to the increase in iso-paraffins. The products consist of paraffins (96.9–99.3%), naphthenes (0.1–1.86%) and aromatics (0.2–1.59%). Aromatization reactions were also taking place in the process which is a considerable benefit of this method as aromatization reactions decrease hydrogen consumption. Moderate hydrogen pressure and H2/feed ratio favour the kerosene yield. The reaction mechanistic pathway was also proposed for converting palm stearin to biofuels. Furthermore, product yield, selectivity, heteroatom removal, and double bond saturation were also explored. The stability and activity of the catalyst were studied for 600 h without observable deactivation of the catalyst.

Natural p-n Junctions at the MoS2 Flake Edges.

Two-dimensional (2D) semiconductors are holding promises as channel materials for field-effect transistors. Compared to traditional three-dimensional (3D) semiconductors whose electronic and optical properties are hindered by dangling bonds and trap states at the surfaces, 2D materials with saturated chemical bonds on the surface maintain the excellent properties even when device thickness scales down to monolayer. However, dangling bonds are unavoidable at their edges, which are often overlooked and should have important effects on the devices. Here, we show that the edges of as-exfoliated and etched MoS2 are naturally p-type doped and can form p-n junctions with the bulk of the flake. The width of these edge regions is around 20 nm. While their existence could present challenges for the shrinkage of devices, they can be exploited to form rectifying or optoelectronic devices based on a single flake of MoS2 without the need of an elaborate extrinsic doping process.

A novel deep blue emitting material based on carbazole-phenylanthracene conjugate linked by saturated bond: Synthesis, physical properties and organic/inorganic hybrid light emitting diode application

Herein, a novel organic light-emitting material 9-(4-(anthracen-9-yl)benzyl)-9H-carbazole (AnPhylCz) was synthesized by linking carbazole to 9-phenylanthracene with methylene (saturated bond). Their thermal, photophysical properties and the application as organic/inorganic hybrid light-emitting diodes (LEDs) were investigated. The Td (decomposition temperature, 5% weight loss) for AnPhylCz was estimated to be 304 °C because the methylene linked with nitrogen-atom (C–N bond) in the molecule is easily broken by heat. The photoluminescence (PL) spectrum of AnPhylCz in each solvent mainly shows one main peak (423 nm) and one shoulder (403 nm) locating at deep blue region. The organic/inorganic hybrid LED (device GXC-B) based on AnPhylCz shows deep blue emission with Commission Internationale de l'Eclairage chromaticity coordinate of (0.1598, 0.0481) at 29.90 mA, and device GXC-B exhibits lifetime of 12.7 min due to the homolytic reaction of AnPhylCz (C–N bond) under ultraviolet. In contrast the lifetime of organic/inorganic hybrid LED is not improved by adopting the organic light-emitting material which linking the luminescent units with saturated bond.

Structural, morphological, and linear/non-linear optical properties tuning in Ag60-xSe40Tex films by thermal annealing for optoelectronics

The effect of annealing on 800 nm thickness Ag60-xSe40Tex thin films were taken into account for their structural, surface morphology, and optical properties change for possible optoelectronic applications. The detailed analysis by X-ray diffraction and Raman study showed the structural change of the annealed thin films. The elemental% of the films was checked by Energy dispersive X-ray analysis and the surface scanning was done by field emission scanning electron microscopy. The transmission data were recorded by UV–Visible spectroscopy from which both nonlinear and linear entities are calculated based on empirical formulas. The formation of saturated bonds on annealing consequently influenced the different optical parameters for which the extinction coefficient increased and the optical bandgap decreased. There is an increase in linear refractive index, plasma frequency, carrier concentration, high-frequency dielectric constant, and optical electronegativity. In contrast, other essential properties such as χ3,χ1, and n2 decreased with an increase in Te% upon annealing. The observed optical changes upon thermal annealing are useful for optoelectronics and solar cell application.

Ene-Reductase: A Multifaceted Biocatalyst in Organic Synthesis.

Biocatalysis integrate microbiologists, enzymologists, and organic chemists to access the repertoire of pharmaceutical and agrochemicals with high chemoselectivity, regioselectivity, and enantioselectivity. The saturation of carbon-carbon double bonds by biocatalysts challenges the conventional chemical methodology as it bypasses the use of precious metals (in combination with chiral ligands and molecular hydrogen) or organocatalysts. In this line, Ene-reductases (ERs) from the Old Yellow Enzymes (OYEs) family are found to be a prominent asymmetric biocatalyst that is increasingly used in academia and industries towards unparalleled stereoselective trans-hydrogenations of activated C=C bonds. ERs gained prominence as they were used as individual catalysts, multi-enzyme cascades, and in conjugation with chemical reagents (chemoenzymatic approach). Besides, ERs' participation in the photoelectrochemical and radical-mediated process helps to unlock many scopes outside traditional biocatalysis. These up-and-coming methodologies entice the enzymologists and chemists to explore, expand and harness the chemistries displayed by ERs for industrial settings. Herein, we reviewed the last five year's exploration of organic transformations using ERs.

Permeation of vegetable oils and slippery properties of extrusion coated paperboard

AbstractDue to the ability of oils to penetrate into the structure of polymers, it is possible to create slippery surfaces with low water droplet sliding angles based on polymer coatings. Polylactic acid, polybutylene succinate and low‐density polyethylene extrusion coatings were used as such surfaces in this study. The process of penetration of vegetable oils into the polymers was studied with the subsequent investigation of slippery behaviour of such system. Cottonseed oil and castor oil showed promising properties as lubricants. For oil infused polymer surfaces the water droplet sliding angles were significantly lower than for the untreated extrusion coating. The penetration of the permeant into the upper layers of the coating was confirmed by alteration of the static water contact angle, sliding angle and also by the cross section images. LDPE extrusion coating infused with castor oil showed the lowest water sliding angle − 8°. Biopolymers, being a main focus in this study, exhibited also promising results, PLA reached sliding angle of 14° with both olive and castor oil. Dependence of polymer permeability on various factors is rather complex and the wide range of oils used in this work helps to interpret the barrier performance of the studied materials. Degree of bond saturation, viscosity and polarity were found to influence mostly on the oil permeation through the studied polymers.

High Density Polyethylenes Bearing Isolated In-Chain Carbonyls*.

Polyethylene materials are highly important polymers which are produced in the largest volume among all plastics. Due to the chemical inert property of saturated carbon-carbon bonds, the degradation of polyethylene is extremely challenging, which prevents them from efficient chemical recycling. Installing functional groups in the main chain of polyethylenes may facilitate the degradation and following chemical recycling of polyethylene materials. Here we report a highly selective approach for the synthesis of high density polyethylenes bearing low content isolated in-chain carbonyls. Linear high-molecular weight polyethylene chains are synthesized via the palladium catalyzed copolymerization of ethylene with metal carbonyls. Different from traditional ethylene/CO copolymerization reactions, excellent non-alternating selectivity has been achieved. While the properties of polyethylene have been retained in the copolymer, faster degradation compared with that of polyethylene was observed upon UV light irradiation. The synthesized materials may therefore serve as more environmentally friendly alternative plastics than traditional polyethylene materials.

A new synthesis approach for the generation of single chain CP mixtures composed of a few major compounds

Chlorinated paraffins (CPs) are complex mixtures, which consist of thousands of individual compounds with no dominant representative. Consequently, knowledge on structure and environmental relevance of individual CP congeners is poor. Similarly to the synthesis of individual CPs, the generation of less complex CP mixtures that can be thoroughly analyzed may be used to overcome some drawbacks of the highly complex technical CP mixtures. Here, we present a new synthesis approach to generate such simple CP mixtures by decarboxylation of polyunsaturated fatty acids followed by saturation of the double bonds by chlorination. Specifically, α-linolenic acid (18:3Δ9,12,15) was decarboxylated to heptadecatriene. The resulting raw product was chlorinated with SO2Cl2. Purification by column chromatography led to a main fraction consisting of four major peaks originating from hexachloroheptadecane (C17H30Cl6) isomers (∼80% of the total peak area) along with ∼20 low abundant by-products, according to gas chromatography with electron capture negative ion mass spectrometry. In the same way, decarboxylation and subsequent chlorination of other polyunsaturated fatty acids may lead to further simple CP mixtures with other chain lengths. Although these simple CP mixtures cannot fully reflect the various structural features present in technical mixtures they could be beneficial for transformation studies because changes in the CP pattern can easily be noted which is in contrast to technical CP mixtures. Such simple CP mixtures could also be used in toxicity tests which are difficult to perform with technical CP mixtures because of their high complexity.

High-Temperature Stability and Pyrolysis Kinetics and Mechanism of Bio-Based and Petro-Based Resins Using TG–FTIR/MS

Pyrolysis behavior of resins is essential for their high-temperature application. Herein, the high-temperature stability and pyrolysis kinetics and mechanism of rosin glyceride (RGE), hydrogenated rosin glyceride (HRGE), C9 petro-based resin (C9PR), and hydrogenated C9 petro-based resin (HC9PR) under a nonoxidizing atmosphere were investigated by thermogravimetry coupled with Fourier transform infrared spectrometry or mass spectrometry (TG–FTIR/MS) techniques. Friedman and Starink methods as well as reaction-order and truncated Sestak–Berggren models were used to evaluate kinetic and thermodynamic parameters, and results indicated that f(α) = (1 – α)n was the most probable pyrolysis mechanism for different resins. In addition, the average activation energies for pyrolysis of RGE, HRGE, C9PR, and HC9PR obtained by the Starink method were 188.97, 170.95, 159.69, and 151.66 kJ/mol, respectively, suggesting that bio-based resins exhibited better high-temperature stability than cycloaliphatic or aromatic petro-based resins thanks to their unique tricyclic phenanthrene structures, and the high-temperature stability of resins mildly would decrease after hydromodification due to the cracking of saturated bonds, which was well supported by TG–FTIR/MS analyses. Possible pyrolysis pathways were proposed.

Arsenic removal from water by graphene nanoplatelets prepared from nail waste: A physicochemical study of adsorption based on process optimization, kinetics, isotherm and thermodynamics

Graphene nanoplatelet derived from human nail was synthesized through a novel synthetic in-situ methodology by using ferric chloride. XPS was performed to scrutinize defects and the percentage of saturated and unsaturated bonds of carbon. Pseudo second order kinetic equation vividly described the nature of the sorption of As(III) on GN surface. Response surface methodology and analysis of variance were used to optimize the reaction parameters. The Langmuir isotherm equation explicitly demonstrated layer dependant sorption phenomenon. The sorption efficiency by GN at lower As (III) concentration range, was observed to be ~99% (247.22 mmol.kg−1) at 300 K, whereas the sorption reaction was endothermic (ΔH0 = +15.09 kJ mol−1) as well as spontaneous (ΔG0 = −0.90 to −3.16 kJ mol−1, and the positive entropy (ΔS0 = +0.05 kJ mol−1K−1) at interface was the driving force of the adsorption reaction.

Molecular simulation study of the adhesion work for water droplets on water monolayer at room temperature* *Project supported by the National Natural Science Foundation of China (Grant Nos. 12022508 and 12074394) and Sichuan Science and Technology Program (Grant No. 2017YJ0174).

The wetting phenomenon of water droplets coexisting with the ordered water monolayer termed an unexpected phenomenon of “water that does not wet a water monolayer” at room temperature has been found on several solid surfaces. Although the hydrogen bond saturation inside the monolayer can qualitatively describe this phenomenon, whether the Young–Dupré equation still holds under this unconventional wetting framework is still not answered. In this work, we have calculated the contact angle values of the droplets as well as the work of adhesion between the droplets and the monolayer based on an extended phantom-wall method. The results show that similar to the conventional solid–liquid interface, classical Young–Dupré equation is also applicable for the interface of liquid water and ordered water monolayer.

Study on efficiency of corrosion inhibitors based on derivatives of isothiuronic salts

Metals play a pivotal role in industry; their use constantly grows. It is virtually impossible to find an industrial field without the use of metals and their alloys. However, owing to the quality degradation of metal during the operational process, corrosion appears not only on its surface but also under a coating, which leads to its destruction. To avoid this, corrosion inhibitors are necessary. Organic compounds have been widely used as corrosion inhibitors. Many organic corrosion inhibitors have been developed nowadays. In the literature, organic compounds comprising N, O, S and P heteroatoms are described, which reduce corrosion rate. The organic compounds are adsorbed on the metal surface, forming a thin layer. Adsorption occurs either through electrostatic interaction or, in some cases, the formation of covalent bonds. The work aimed to study isothiuronic salts as corrosion inhibitors to evaluate their protective properties using the polarisation curves method. Objects of research were isothiuronic compounds containing two active centres separated by saturated and unsaturated carbon bonds (structures 1-3). In structures 4-7, one isothiuronic fragment has different propylene substituting groups. It has been previously shown that these compounds can act as effective brightening agents when applying nickel coatings. A model solution with a density of 1.12 g/cm3 was prepared to study the corrosion inhibitors. The corrosion inhibitor concentration was 400 mg/L. Studies have shown that the compounds with two isothiuronic moieties do not always exhibit improved properties for inhibiting metal degradation in a corrosive environment. In particular, they showed worsening of the inhibiting properties for samples made of steel 20 and identical properties for that made of steel 3.

Robust and High Photoluminescence in WS2 Monolayer through In Situ Defect Engineering

AbstractThe photoluminescence quantum yield (PLQY) of the chemical vapor deposition (CVD) grown transition‐metal dichalcogenides (TMDs) films is often much lower than their mechanically exfoliated counterparts, making the coexistence of large‐area and high PLQY in TMDs monolayer a huge challenge. Here, an in situ defect engineering strategy is reported to fundamentally dilutes the impact of intrinsic sulfur vacancy on tungsten disulfide (WS2) monolayer. By ingeniously incorporating oxygen atoms in the sulfur vacancy sites of WS2 lattice via the CVD method, oxygen doped WS2 monolayer exhibits remarkably improved optical properties. The PLQY is uniformly enhanced by nearly two orders and can reach up to 9.3%, which is even higher than mechanically exfoliated counterparts. Besides, strong W‐O bonds endow materials with superior environment stability, and the high PLQY could persist with an endurance of up to 3 months under ambient conditions without any protection. More in‐depth insights from the first‐principle calculations illustrate that the enhancement mechanism is the synthetic action of the suppression of nonradiative recombination and conversion from trion to neutral, and the excellent stability arises from repaired saturated coordination bonds at sulfur vacancy sites. This method opens up more possibilities for both fundamental exciton physics and optoelectronics applications.