Stable carbamate pathway towards organic–inorganic hybrid perovskites and aromatic imines

Methyl ammonium methyl carbamate (MAC), formulated as CH₃NH₃⁺CH₃NHCO₂⁻, was synthesized by reacting liquid methylamine with supercritical CO₂, and its structure was refined by single-crystal X-ray diffraction. MAC is a white crystalline salt and is as reactive as methylamine, and is a very efficient alternative to toxic methylamine. We were able to produce hybrid perovskite MAPbI₃ (MA = methyl ammonium) by grinding MAC with PbI₂ and I₂ at room temperature, followed by storing the mixed powder. Moreover, this one-pot method is easily scalable for the large-scale synthesis of MAPbI₃ in a small vessel. We have also investigated the reactivity of MAC towards aromatic aldehydes in the absence of solvent. The solventless reactions afforded imines as exclusive products with over 97% yield, which show higher selectivity than the methylamine-based synthesis. Complete conversions were typically accomplished within 3 h at 25 °C. The results of this study emphasize the importance of solid carbamates such as MAC to develop an environmentally friendly process for the synthesis of various amine-based materials on the industrial scale.

A stable solid carbamate (MAC) composed of CH₃NH₃⁺ and CH₃NHCO₂⁻ units exhibits high reactivity toward inorganic iodide and aromatic aldehyde.     

Novel organic–inorganic hybrid powder SrGa12O19:Mn2+–ethyl cellulose for efficient latent fingerprint recognition via time-gated fluorescence

Latent fingerprints (LFPs) are important evidence in crime scenes and forensic investigations, but they are invisible to the naked eye. In this work, a novel fluorescent probe was developed by integrating a narrow-band-emitting green afterglow phosphor, SrGa₁₂O₁₉:Mn²⁺ (SGO:Mn), and ethyl cellulose (EC) for the efficient visualization of LFPs. The hydrophobic interactions between the powder and lipid-rich LFPs made the ridge structures more defined and easily identifiable. The background fluorescence of the substrates was completely avoided because of the time-gated fluorescence of the afterglow phosphor. All the three levels of LFP degrees were clearly imaged due to the high sensitivity. Moreover, the SGO:Mn–EC powder was highly stable in neutral, acidic, and alkaline environments. In addition, 60 day-aged LFPs were successfully visualized by the powder. All performances showed that this strategy for LFP recognition has merits such as low cost, non-destructive nature, reliability, superior universality, and legible details. Together, these results show the great application prospects of this powder in forensic identification and criminal investigation.

A easy and efficient strategy for latent fingerprints recognition was developed by this work.     

Thermal property and structural molecular dynamics of organic–inorganic hybrid perovskite 1,4-butanediammonium tetrachlorocuprate

We investigate the thermal behaviour and physical properties of the crystals of the organic inorganic hybrid perovskite [(NH₃)(CH₂)₄(NH₃)]CuCl₄. The compound''s thermal stability curve as per thermogravimetric analysis exhibits a stable state up to ∼495 K, while the weight loss observed near 538 K corresponds to partial thermal decomposition. The ¹H nuclear magnetic resonance (NMR) chemical shifts for NH₃ change more significantly with temperature than those for CH₂, because the organic cation motion is enhanced at both ends of the organic chain. The ¹³C NMR chemical shifts for the ‘CH₂-1’ units of the chain show an anomalous change, and those for ‘CH₂-2’ (units closer to NH₃) are shifted sharply. Additionally, the ¹⁴N NMR spectra reflect the changes of local symmetry near T_C (=323 K). Moreover, the ¹³C T_1ρ values for CH₂-2 are smaller than those for CH₂-1, and the ¹³C T_1ρ data curve for CH₂-1 exhibits an anomalous behaviour between 260 and 310 K. These smaller T_1ρ values at lower temperatures indicate that ¹H and ¹³C in the organic chains are more flexible at these temperatures. The NH₃ group is attached to both ends of the organic chain, and NH₃ forms a N–H⋯Cl hydrogen bond with the Cl ion of inorganic CuCl₄. When H and C are located close to the paramagnetic Cu²⁺ ion, the T_1ρ value is smaller than when these are located far from the paramagnetic ion.

We investigate the thermal behaviour and physical properties of the crystals of the organic inorganic hybrid perovskite [(NH₃)(CH₂)₄(NH₃)]CuCl₄.     

Preparation of core/shell organic–inorganic hybrid polymer nanoparticles and their application to toughening poly(methyl methacrylate)

On account of the utility of poly(methyl methacrylate) (PMMA) as a glass substitute, toughening of PMMA has attracted significant attention. Brittle failure can often be avoided by incorporating a small fraction of filler particles. Core–shell composite particles composed of a rubbery core and a glassy shell have recently attracted interest as a toughening agent for brittle polymers. Here, core/shell organic–inorganic hybrid polymer nanoparticles (Si-ASA HPNs) with a silicone-modified butyl acrylate copolymer (PBA) core and a styrene-acrylonitrile copolymer (SAN) shell were used to toughen PMMA. Silicone plays dual roles as a compatibilizer and a chain extender, and it not only improves interfacial adhesion between the PBA particles and SAN copolymer, but it also increases chain entanglement of poly(acrylonitrile-styrene-acrylate) (ASA). The mechanical properties of the PMMA/ASA alloys strongly depend on the Si content, and the impact strength and elongation at break greatly improve when silicone-modified ASA is added. However, this is accompanied by loss of rigidity. Specifically, the PMMA/ASA-2 composite exhibits a good balance between toughness and rigidity, indicating that ASA-2 with 5 wt% KH570 is the most suitable impact modifier. This research provides a facile and practical method to overcome the shortcomings of ASA and promote its application in a wider range of fields.

Core/shell organic–inorganic hybrid polymer nanoparticles are synthesized by micellar nucleation, core enlarged polymerization and a grafting reaction in the system.     

Efficient and chromaticity stable green and white organic light-emitting devices with organic–inorganic hybrid materials

Efficient inverted bottom emissive organic light emitting diodes (IBOLEDs) with tin dioxide and/or Cd-doped SnO₂ nanoparticles as an electron injection layer at the indium tin oxide cathode:electron transport layer interface have been fabricated. The SnO₂ NPs promote electron injection efficiently because their conduction band (−3.6 eV) lies between the work function (W_f) of ITO (4.8 eV) and the LUMO of the electron-transporting molecule (−3.32 eV), leading to enhanced efficiency at low voltage. The 2.0% SnO₂ NPs (25 nm) with Ir(ddsi)₂(acac) emissive material (SnO₂ NPs/ITO) have an enhanced current efficiency (η_c, cd A⁻¹) of 52.3/24.3, power efficiency (η_p, lm W⁻¹) of 10.9/3.4, external quantum efficiency (η_ex, %) of 16.4/7.5 and luminance (L, cd m⁻²) of 28 182/1982. A device with a 2.0% Cd-doped SnO₂ layer shows higher η_c (60.6 cd A⁻¹), η_p (15.4 lm W⁻¹), η_ex (18.3%) and L (26 858 cd m⁻²) than SnO₂ devices or control devices. White light emission was harvested from a mixture of Cd–SnO₂ NPs and homoleptic blue phosphor Ir(tsi)₃; the combination of blue emission (λ_EL = 428 nm) from Ir(tsi)₃ and defect emission from Cd–SnO₂ NPs (λ_EL = 568 nm) gives an intense white light with CIE of (0.31, 0.30) and CCT of 6961 K. The white light emission [CIE of (0.34, 0.35) and CCT of 5188 K] from colloid hybrid electrolyte BMIMBF₄–SnO₂ is also discussed.

Efficient inverted bottom emissive organic light emitting diodes (IBOLEDs) with tin dioxide and/or Cd-doped SnO₂ nanoparticles as an electron injection layer at the indium tin oxide cathode:electron transport layer interface have been fabricated.     

A dual-functional luminescent Tb(iii) metal–organic framework for the selective sensing of acetone and TNP in water

Herein, a novel water-stable luminescent terbium metal–organic framework, {[Tb(L₁)(L₂)_0.5(NO₃)(DMF)]·DMF}_n (TPA-MOF), with 1,10-phenanthroline (phen) and 3,3′,5,5′-azobenzene-tetracarboxylic acid (H₄abtc) ligands was solvothermally synthesized and structurally characterized. TPA-MOF possesses a two-dimensional (2D) extended framework featuring an 8-connected uninodal SP2-periodic net topology with the Schläfli point symbol of {3^12;4^14;5^2}. The π-electron rich luminescent TPA-MOF exhibits four characteristic emission bands of Tb³⁺ ion and acts as a selective and sensitive probe for acetone as well as the electron deficient 2,4,6-trinitrophenol (TNP). Moreover, gas sorption studies confirm that TPA-MOF displays ultra-micropores and adsorbs moderate amounts of N₂ and CO₂.

A novel 2D luminescent terbium metal–organic framework demonstrating highly efficient and selective sensing for acetone and 2,4,6-trinitrophenol (TNP) in an aqueous solution was solvothermally synthesized and structurally characterized.     

Efficient and chromaticity-stable flexible white organic light-emitting devices based on organic–inorganic hybrid color-conversion electrodes

We have developed a novel organic–inorganic hybrid color conversion electrode composed of Ag NWs/poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) via a solution process, which is the first report on a color conversion electrode for applications in flexible optoelectronics. Using the Ag NWs/MEH-PPV composite film as the anode on polyethylene terephthalate substrate and combined with a blue organic light emitting devices (OLEDs) unit employing bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(iii)) (Flrpic) in 1,3-bis(carbazol-9-yl)benzene (mCP) as the emitting layer, a highly efficient and chromaticity-stable color-conversion flexible white OLEDs (WOLEDs) is achieved with a maximum current efficiency of 20.5 cd A⁻¹. To the best of our knowledge, this is the highest efficiency reported for color-conversion based flexible WOLEDs. Our work provides an approach to achieving high-performance flexible WOLEDs devices and demonstrates great potential for lighting and display applications.

We have developed a novel color conversion electrode composed of Ag NWs/MEH-PPV via a solution process, which is the first report on a color conversion electrode for applications in flexible optoelectronics.     

Improving the performance of quantum-dot light-emitting diodes via an organic–inorganic hybrid hole injection layer

Poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) is a commonly used material for the hole injection layer (HIL) in quantum-dot light-emitting diodes (QLEDs). In this work, we improved the performance of the QLED by using an organic–inorganic hybrid HIL. The hybrid HIL was prepared by mixing PEDOT:PSS with vanadium oxide (V₂O₅), which is a transition-metal oxide (TMO). The hole injection properties of PEDOT:PSS were improved according to the amount of V₂O₅ mixed into the PEDOT:PSS. The maximum luminance and current efficiency were 36 198 cd m⁻² and 13.9 cd A⁻¹, respectively, when the ratio of PEDOT:PSS and V₂O₅ was 10 : 1. Moreover, the operating lifetime exceeded 300 h, which is 10 times longer than the lifetime of the device with only PEDOT:PSS HIL. The improvement was analyzed using ultraviolet and X-ray photoelectron spectroscopy. We found that the density of state (DOS) of PEDOT:PSS near the Fermi energy level was increased by mixing V₂O₅. Therefore, the increase of DOS improved the hole injection and the performance of QLEDs. The result shows that the hybrid HIL can improve the performance and the stability of QLEDs.

The performance of the quantum-dot light-emitting diodes was improved by using an organic–inorganic hybrid hole injection layer.     

Ag–Au bimetallic nanocomposites stabilized with organic–inorganic hybrid microgels: synthesis and their regulated optical and catalytic properties

Herein, we present the synthesis of Ag–Au bimetallic nanocomposites stabilized with organic–inorganic hybrid microgels. The aim is to get both the surface plasmon resonance (SPR) and catalytic performance of the composite material can be changed in response to external stimuli. Ag@poly(N-isopropylacrylamide-co-3-methacryloxypro-pyltrimethoxysilane) (Ag@P(NIPAM-co-MAPTMS)) hybrid microgels were synthesized by seed-emulsion polymerization using Ag nanoparticles (NPs) as the core and NIPAM/MAPTMS as monomers. Ag–Au@P(NIPAM-co-MAPTMS) bimetallic hybrid microgels were prepared by a galvanic replacement (GR) reaction between Ag NPs and HAuCl₄, with the composition and structure of these bimetallic nanocomposites being determined by the amount of added HAuCl₄. The highly porous organic–inorganic microgel layer provided confined space for the GR reaction, effectively preventing the aggregation of Ag–Au NPs. The shell layer of P(NIPAM-co-MAPTMS) three-dimensional network chains not only enhanced nanocomposite dispersity and stability, but also provided highly porous gel microdomains that could increase the diffusion of the substrate and hence enhanced catalytic activity. Additionally, the SPR and catalytic properties of Ag–Au@P(NIPAM-co-MAPTMS) are reversibly sensitive to external temperature. With increase of temperature, the maximum absorption peak of bimetallic nanocomposites shifted to longer wavelengths, and the catalytic activity of these composites for the reduction of 4-nitrophenol by NaBH₄ remarkably increased. The features above mentioned are related to presence of the thermosensitive PNIPAM chains and the highly porous structure constructed by rigid MAPTMS segments intersected between NIPAM chains.

Ag–Au bimetallic nanocomposites stabilized with organic–inorganic hybrid microgels allowed the mass transfer of reactants to be controlled by temperature modulation.     

A low cost,superhydrophobic and superoleophilic hybrid kaolin-based hollow fibre membrane (KHFM) for efficient adsorption–separation of oil removal from water

Inspired by the lotus leaf surface structure, which possesses a hydrophobicity behaviour, a low cost, high performance superhydrophobic and superoleophilic kaolin hollow fibre membrane (KHFM) was obtained by a simple sol–gel grafted method using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) for oil removal from water. The KHFM was grafted at various grafting times ranging from 1 to 5 coating cycles. Prior to the calcination process at 400 °C, the grafted KHFM was dried in an oven at 100 °C for 1 hour for each grafting coating cycle. The grafting process efficiency was measured by the contact angle of water and hexane. Scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM) were used to study the morphology and surface roughness, respectively, of the grafted KHFM. The oil removal was conducted by using the homogeneous mixture of hexane and water. The highest hydrophobicity and oleophilicity was obtained for the KHFM grafted at 2 coating cycles with a contact angle value equal to 157° and 0°, respectively. In fact, the mechanical strength of KHFM was also improved from 16.21 MPa to 72.33 MPa after grafting. In terms of performance, KHFM grafted for 2 coating cycles obtained an almost 99.9% absorption of oil. Thereby, KHFMs were assembled into a module for a filtration study. A high oil flux of 102 L m⁻² h⁻¹ was obtained for superhydrophobic and superoleophilic KHFM with 2 grafting coating cycles of 2, and this result is in agreement with the trend of the adsorption result.

This paper outlines a low cost, high performance superhydrophobic/superoleophilic KHFM through a simple sol–gel grafted method using TEOS and MTES for efficient adsorption–separation of oil removal from water.     

Thermal and structural properties,and molecular dynamics in organic–inorganic hybrid perovskite (C2H5NH3)2ZnCl4

The thermal and structural properties and molecular dynamics of layered perovskite-type (C₂H₅NH₃)₂ZnCl₄ are investigated by differential scanning calorimetry, thermogravimetric analysis, and magic angle spinning nuclear magnetic resonance spectroscopy. The thermal properties and phase transitions are studied. Additionally, the Bloembergen–Purcell–Pound (BPP) curves for the ¹H spin–lattice relaxation time T_1ρ in the C₂H₅NH₃ cation and for the ¹³C T_1ρ in C₂H₅ are shown to have minima as a function of inverse temperature. This observation implies that these curves represent the rotational motions of ¹H and ¹³C in the C₂H₅NH₃ cation. The activation energies for ¹H and ¹³C in the C₂H₅NH₃ cation are obtained; the molecular motion of ¹H is enhanced at the C-end and N-end of the organic cation, and that at the carbons of the main chain is not as free as that for protons at the C-end and N-end.

The thermal and structural properties and molecular dynamics of layered perovskite-type (C₂H₅NH₃)₂ZnCl₄ are investigated by DSC, TGA, and MAS NMR spectroscopy.     

Hybrid organic–inorganic membranes based on sulfonated poly (ether ether ketone) matrix and iron-encapsulated carbon nanotubes and their application in CO2 separation

The need to reduce greenhouse gas emissions dictates the search for new methods and materials. Here, a novel type of inorganic–organic hybrid materials Fe@MWCNT-OH/SPEEK (with a new type of CNT characterized by increased iron content, 5.80 wt%) for CO₂ separation is presented. The introduction of nanofillers into a polymer matrix has significantly improved hybrid membrane gas transport (D, P, S, and α_CO2/N2), and magnetic, thermal, and mechanical parameters. It was found that magnetic casting has improved the alignment and dispersion of Fe@MWCNT-OH carbon nanotubes. At the same time, CNT and polymer chemical modification enhanced interphase compatibility and membrane CO₂ separation efficiency. The thermooxidative stability, and mechanical and magnetic parameters of composites were improved by increasing new CNT loading. Cherazi''s model turned out to be suitable for describing the CO₂ transport through analyzed hybrid membranes. The comparison of the transport and separation properties of the tested membranes with the literature data indicates their potential application in the future and the direction of further research.

Fe@MWCNT-OH/SPEEK hybrid membranes for CO₂ separation! Significant improvement of hybrid membrane''s gas transport, magnetic, thermal, and mechanical parameters. Enhancement of interphase compatibility after CNT and polymer chemical modification.     

Cation dynamics by 1H and 13C MAS NMR in hybrid organic–inorganic (CH3CH2NH3)2CuCl4

To understand the dynamics of the cation in layered perovskite-type (CH₃CH₂NH₃)₂CuCl₄, the temperature-dependent chemical shifts and spin–lattice relaxation times T_1ρ in the rotating frame have been measured using ¹H magic angle spinning nuclear magnetic resonance (MAS NMR) and ¹³C cross-polarization (CP)/MAS NMR techniques. Each proton and carbon in the (CH₃CH₂NH₃)⁺ cation is distinguished in MAS NMR spectra. The Bloembergen–Purcell–Pound (BPP) curves for ¹H T_1ρ in CH₃CH₂ and NH₃, and for the ¹³C T_1ρ in CH₃ and CH₂ are revealed to have minima at low temperatures. This implies that the curves represent the CH₃ and NH₃⁺ rotational motions. The amplitude of the cationic motion is enhanced at the C-end, that is, the N-end of the organic cation is fixed to the inorganic layer through N–H⋯Cl hydrogen bonds, and T_1ρ becomes short with larger-amplitude molecular motions.

To understand the dynamics of the cation in layered perovskite-type (CH₃CH₂NH₃)₂CuCl₄, the temperature-dependent chemical shifts and spin–lattice relaxation times T_1ρ have been measured using ¹H MAS NMR and ¹³C CP/MAS NMR techniques.     

Novel crystalline organic–inorganic hybrid silicate material composed of the alternate stacking of semi-layered zeolite and microporous organic layers

A novel type of crystalline organic–inorganic hybrid microporous silicate material, KCS-5, was synthesized supposedly from a lamellar precursor composed of amphiphilic organosilicic acids. This well-ordered material has a crystalline structure, is thermally stable up to 500 °C and has lipophilic 1-dimensional micropores.

A novel crystalline organic–inorganic hybrid microporous silicate material was successfully synthesized from a lamellar precursor composed of amphiphilic organosilicic acids.

Organic–inorganic hybridization of silicate materials has been diligently studied because it can control surface properties to improve their adsorption capacities and catalytic activities. In these studies, bridged organosilanes, where an organic group connects two trialkoxysilyl species, are frequently employed as a silicon source. For example, Shea et al. prepared microporous amorphous materials named bridged polysilsesquioxanes¹ by sol–gel synthesis from various organosilanes with bulky bridging organic groups, such as bis(triethoxysilyl)benzene (BTEB), and Inagaki et al. obtained surfactant-templated hexagonally-ordered mesoporous silicates from organosilanes bridged with aliphatic or aromatic organic groups.² Tatsumi et al. discovered an improvement in catalytic activities and surface hydrophobicity through the syntheses of a mesoporous titanosilicate³ and zeolites⁴ from bridged organosilanes. In particular, Bellussi et al. crystallized microporous aluminosilicates called ECS,⁵ composed of layered aluminosilicate and bridging organic groups. Such bridged organosilanes were used as a single silicon source, presumably because they can theoretically build a three-dimensional silicate framework without introducing structural defects.In contrast to bridged organosilanes, terminal organosilanes, where a terminal organic group like a methyl or phenyl group functionalizes trialkoxysilyl species, were not employed as a single silicon source but were subsidiarily added as part of a silicon source because terminal organic groups inevitably cause structural defects which cause a deterioration in the 3-dimensional structure of tectosilicates. However, we conceived an idea to obtain well-ordered materials only from terminal organosilanes inspired by our material KCS-2.⁶ KCS-2, also synthesized using a bridged organosilane BTEB, is a crystalline organic–inorganic hybrid material with a large 12-ring micropore and unique amphiphilic inner surface properties. Considering that the finely-designed layered structure of KCS-2 is similar to that of a Langmuir–Blodgett membrane, it is deduced that KCS-2 is crystallized via a well-ordered lamellar precursor composed of hydrolysed bridged organosilane (Fig. 1 middle). Because a lamellar structure is formed from amphiphilic surfactant molecules (Fig. 1 top), a well-ordered lamellar precursor should also be formed from amphiphilic organosilicic acid molecules made from terminal organosilanes (Fig. 1 bottom). For example, phenyltriethoxysilane (PTES) was hydrolysed into an amphiphilic molecule with a hydrophilic trihydroxysilyl head group and a hydrophobic phenyl group, which would be self-organized into a lamellar phase. Therefore, through the condensation of silicic acid (with aluminum, if necessary), it would be possible to synthesize a crystalline layered (alumino)silicate.Open in a separate windowFig. 1The induced formation scheme of lamellar precursors from bridged and terminal organosilanes.Actually, we have succeeded in synthesizing a novel crystalline silicate material, KCS-5, from PTES as a single silicon source. In a typical synthesis (please refer to ESI^†), a mixture with the molar composition of 1.0 PTES : 1.0 NaOH : 5.0H₂O was stirred at r.t. for 2–4 days to promote the hydrolysis of PTES to amphiphilic organosilicic acid, which could be arranged into a lamellar-structured precursor. After the addition of fumed alumina powder (Al₂O₃/Si = 0.2), this mixture was hydrothermally treated at 100 °C for 7 days under static conditions. Generally, KCS-5 was obtained preferentially from mixtures with low H₂O/PTES ratios, where the concentration of amphiphilic organosilicic acid was high. In addition, no crystalline products were obtained from this organosilane without the addition of an aluminum source. Fig. 2 exhibits the powder X-ray diffraction (PXRD) pattern of KCS-5. A low and wide background ranging from 15° to 40° would be derived from a concomitant amorphous by-product and a borosilicate glass capillary tube. By an indexing analysis, the lattice constant belonging to an orthorhombic system was uniquely found. A crystal structure model of KCS-5 was tentatively built from local structural units, such as SiO₄, AlO₄ and C₆H₅–SiO₃, elucidated from the solid-state NMR. (The ²⁹Si, ²⁷Al, and ¹³C solid-state MAS NMR spectra are shown in ESI.^†) The packing structure of these units was solved by the direct-space method with the parallel tempering algorithm using the program FOX.⁷8 using the program RIETAN-FP.⁹ Reliability factors obtained in this analysis were small enough. The calculated and difference plots obtained by the Rietveld analyses are also exhibited in Fig. 2.Open in a separate windowFig. 2Observed (red) and calculated (light blue), background (black), and difference (blue) intensity curves of KCS-5 obtained by Rietveld refinement. The green tick marks denote the peak positions of possible Bragg reflections.Conditions for the PXRD experiments and crystallographic information obtained therein for KCS-5

A review on organic–inorganic hybrid nanocomposite membranes: a versatile tool to overcome the barriers of forward osmosis

Forward osmosis (FO) processes have recently attracted increasing attention and show great potential as a low-energy separation technology for water regeneration and seawater desalination. However, a number of challenges, such as internal concentration polarization, membrane fouling, and the trade-off effect, limit the scaleup and industrial practicality of FO. Hence, a versatile method is needed to address these problems and fabricate ideal FO membranes. Among the many methods, incorporating polymeric FO membranes with inorganic nanomaterials is widely used and effective and is reviewed in this paper. The properties of FO membranes can be improved and meet the demands of various applications with the incorporation of nanomaterials. This review presents the actualities and advantages of organic–inorganic hybrid nanocomposite FO membranes. Nanomaterials applied in the FO field, such as carbon nanotubes, graphene oxide, halloysite nanotubes, silica and Ag nanoparticles, are classified and compared in this review. The effects of modification methods on the performance of nanocomposite FO membranes, including blending, in situ interfacial polymerization, surface grafting and layer-by-layer assembly, are also reviewed. The outlook section discusses the prospects of organic–inorganic hybrid nanocomposite FO membranes and advanced nanotechnologies available for FO processes. This discussion may provide new opportunities for developing novel FO membranes with high performance.

Nanocomposite forward osmosis (FO) membranes have attracted increasing attentions recently and showed great comprehensive performance. Various modification methods have been employed to incorporate inorganic nanomaterials to FO membranes.     

Organic–inorganic hybrid perovskite for low-cost and high-performance xerographic photoreceptors

Solution-processable organic–inorganic hybrid perovskites are being widely investigated for many applications, including solar cells, light-emitting diodes, photodetectors, and lasers. Herein, we report, for the first time, successful fabrication of xerographic photoreceptors using methylammonium lead iodide (CH₃NH₃PbI₃) perovskite as a light-absorbing material. With the incorporation of polyethylene glycol (PEG) into the perovskite film, the ion migration inherent to the perovskite material can be effectively suppressed, and the resulting photoreceptor exhibits a high and panchromatic photosensitivity, large surface potential, low dark decay, and high environmental resistance and electrical cycling stability. Specifically, the energies required to photodischarge one half of the initial surface potential (E_0.5) are 0.074 μJ cm⁻² at 550 nm and 0.14 μJ cm⁻² at 780 nm, respectively. The photosensitivites outmatch those of the conventionally used organic pigments having narrow spectral responses. Our findings inform a new generation of highly efficient and low-cost xerographic photoreceptors based on perovskite materials.

MAPbI₃ perovskite is first used as a light-absorbing charge-generating material for xerographic photoreceptors. The resultant photoreceptor exhibits excellent xerographic properties, and good environmental and electrical cycling stability.     

Crystal structures,phase transitions,and nuclear magnetic resonance of organic–inorganic hybrid [NH2(CH3)2]2ZnBr4 crystals

Organic–inorganic hybrid [NH₂(CH₃)₂]₂ZnBr₄ crystals were grown via slow evaporation, and their monoclinic structure was determined using single-crystal X-ray diffraction (XRD). The two phase transition temperatures at 401 K (T_C1) and 436 K (T_C2) were defined using differential scanning calorimetry and powder XRD. In the nuclear magnetic resonance spectra, a small change was observed in the ¹H chemical shifts for NH₂, ¹³C chemical shifts for CH₃, and ¹⁴N resonance frequency for NH₂ near T_C1. ¹H spin-lattice relaxation times T_1ρ and ¹³C T_1ρ for NH₂ and CH₃, respectively, rapidly decreased near T_C1, suggesting that energy was easily transferred. NH₂ in the [NH₂(CH₃)₂]⁺ cation was significantly influenced by the surrounding environments of ¹H and ¹⁴N, indicating a change in the N–H⋯Br hydrogen bond with the coordination geometry of the ZnBr₄ anion. These fundamental properties open efficient avenues for the development of organic–inorganic hybrids, thus qualifying them for practical applications.

Thermal ellipsoid plot (50% probability) for the [NH₂(CH₃)₂]₂ ZnBr₄ structure at 300 K.     

Insight into the photoelectrical properties of metal adsorption on a two-dimensional organic–inorganic hybrid perovskite surface: theoretical and experimental research

In order to study the photoelectric properties of the adsorption of different metal atoms on a two-dimensional (2D) perovskite surface, in this article, we built many models of Ag, Au, and Bi atoms adsorbed on 2D perovskite. We studied the rules influencing 2D perovskite adsorbing metal atoms with different n values (the n value is the number of inorganic layers of 2D perovskite; here n = 1, 2, and 3). Based on n = 2 2D perovskite, we successively used Ag, Au, and Bi metal atoms to adsorb on the 2D perovskite surface. Firstly, we calculated their adsorption energies. Based on the lowest energy principle, we found that Bi atom adsorption on the 2D perovskite surface gave the most stable structure among the three metal adsorptions because the energy of the Bi adsorption system was the smallest. Secondly, the electron transport process takes place from the s to the p orbital when Au and Ag atoms adsorb on the 2D perovskite surface, but in the Bi atom adsorption, the electron transport process takes place from the p to the p orbital, because the p–p orbital transport energy is lower than that of the s–p orbital. Therefore, Bi atom adsorption on the 2D perovskite surface can improve charge carrier transfer. Thirdly, we calculated the bond angles and bond energies of different metal adsorptions on 2D perovskite. Bi adsorption has greater interaction with the surface atoms of 2D perovskite than Ag or Au atom adsorption, which effectively enhances the surface polarization effects, and enhances the photoelectric properties of 2D perovskite. The light absorption spectrum further confirms that Bi atom adsorption has a greater impact on the 2D perovskite than the action of Ag or Au adsorption. Finally, in an experiment, we fabricated a 2D perovskite solar cell with an ITO/PEDOT:PSS/2D perovskite/PEI/Ag (Au, Bi) structure. The Bi electrode solar cell achieves the highest photoelectric conversion efficiency (PCE) of 15.16% among the three cells with forward scanning, which is consistent with the theoretical analysis. We believe that the adsorption of metals like Bi on a 2D perovskite surface as an electrode is conducive to improving the charge transport performance.

Bi atom adsorption on a 2D perovskite surface structure has the minimum adsorption energy. When it uses on the solar cell electrode, the 2D perovskite solar cell of ITO/PEDOT:PSS/2D perovskite/PEI/Bi structure exhibits the highest photoelectric conversion efficiency (PCE) of 15.16%.     

An organic–inorganic hybrid K2TiF6 : Mn4+ red-emitting phosphor with remarkable improvement of emission and luminescent thermal stability

A new type of monoethanolamine (MEA) and Mn⁴⁺ co-doped KTF : MEAH⁺, Mn⁴⁺ (K₂TiF₆ : 0.1MEAH⁺, 0.06Mn⁴⁺) red emitting phosphor was synthesized by an ion exchange method. The prepared Mn⁴⁺ co-doped organic–inorganic hybrid red phosphor exhibits sharp red emission at 632 nm and the emission intensity at room temperature is 1.43 times that of a non-hybrid control sample KTF : Mn⁴⁺ (K₂TiF₆ : 0.06Mn⁴⁺). It exhibits good luminescent thermal stability at high temperatures, and the maximum integrated PL intensity at 150 °C is 2.34 times that of the initial value at 30 °C. By coating a mixture of KTF : MEAH⁺, Mn⁴⁺, a yellow phosphor (YAG : Ce³⁺) and epoxy resin on a blue InGaN chip, a prototype WLED (white light-emitting diode) with CCT = 3740 K and R_a = 90.7 is assembled. The good performance of the WLED shows that KTF : MEAH⁺, Mn⁴⁺ can provide a new choice for the synthesis of new Mn⁴⁺ doped fluoride phosphors.

KTF : MEAH⁺, Mn⁴⁺ exhibits good luminescent thermal stability at high temperatures, and the maximum integrated PL intensity at 150 °C is 2.34 times the initial value at 30 °C.