Hybrid Organic-inorganic Metal Halide Research Articles

Tunable double emission of Sb3+/Mn2+ doping stabilized organic-inorganic hybrid zinc-based halides

Low-dimensional organic-inorganic hybrid metal halides (OIHMHs) have attracted much attention lately in contrast to all-inorganic metal halides because of their excellent photophysical properties and tunable emission wavelengths. Zn-based metal halides have the following advantages: simplicity of synthesis, wide bandgap, and excellent chemical stability. Therefore, they are well-suited as host materials for photoluminescence by cation ion doping. We have successfully synthesized intrinsically non-emissive 0D (PPZ)ZnCl4 [PPZ (1-phenylpiperazine) = C10H14N2], and by mono/co-doping with Mn2+ and Sb3+, interesting luminescence phenomena have been produced. Single-doped Mn2+ / Sb3+ shows distinctive green and single orange emission, respectively. However, the co-doped Mn2+ and Sb3+ appeared as dynamic double emission peaks at 530nm and 670nm. Therefore, the co-doped crystals showed luminescence from two different luminescence centers ([MnCl4]2- and [SbCl4]-). We used DFT to calculate the DOS (density of states) of co-doped crystals, which results in energy transfer between Mn2+ and Sb3+. All of the above samples showed high stability after being left for two months. In addition, two different luminescence centers can be produced by the adjustment of the excitation of the co-doped (PPZ)ZnCl4: Sb0.12Mn0.08 samples, which is a distinguishable and obvious photoluminescence phenomenon having great potential preparation of advanced anti-counterfeiting materials in the future.

Multimode Luminescence Tailoring in PMA4Na(In,Sb)Cl8 Organic–inorganic Hybrid Metal Halide via Rigid Benzene Ring Induced Local Lattice Distortion

AbstractLow dimensional organic‐inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity‐forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow‐emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low‐dimensional OIMHs single crystal with a PLQY as high as 88 % was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity‐forbidden transition by strong spin‐orbit (SO) coupling and Jahn‐Teller (JT) interaction. The as‐prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1→1S0 transitions of Sb3+ in [SbCl6]3− octahedral caused by JT deformation. Moreover, wide‐range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3− octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti‐thermal quenching from 8 to 400 K owing to the suppression of non‐radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti‐counterfeiting and WLED applications.

Oriented Growth of Highly Emissive Manganese Halide Microrods for Dual-Mode Low-Loss Optical Waveguides.

Zero-dimensional (0D) structured lead-free metal halides have recently attracted widespread attention due to their high photoluminescence quantum yield (PLQY) and negligible self-absorption, showing enormous potential as optical waveguides towards miniaturized photonic devices. However, due to the great difficulty in growth of rod-like nano/micro-sized morphologies, such applications have been less explored. Herein, a new-type emissive organic-inorganic manganese (II) halide crystal (TPS2MnCl4, TPS = C18H15S, triphenylsulfonium) in the form of microrods is synthesized via a facile chloride ion (Cl-) induced oriented growth method. Due to a combination of attractive features such as a high PLQY of 86%, negligible self-absorption and smooth crystal surface, TPS2MnCl4 microrods are well suited for use in optical waveguide with an ultra-low optical loss coefficient of 1.20·10-4 dB μm-1, superior to that of most organic-inorganic metal halide hybrids, organic materials, polymers and metal nanoclusters to the best of our knowledge. Importantly, TPS2MnCl4 microrods can further work as dual-mode optical waveguides, combining active and passive light transmission functionalities in one single crystal. In addition, TPS2MnCl4 microrods also display remarkable performance in lighting and anti-counterfeiting due to their distinct optical properties and commendable stability.

Crystal structure and optical properties of a new 0D Sb-based hybrid metal halide: (3,5-DMP)3Sb2Br9

Zero-dimensional (0D) lead-free hybrid organic-inorganic metal halides (OIMHs) have recently garnered tremendous attention due to their diversified structures and unique structure-dependent photoluminescent (PL) properties. Herein, we report a novel Sb-based 0D hybrid organic-inorganic metal halide (OIMH), with the chemical formula (3,5-DMP)3Sb2Br9 [3,5-DMP+ = 3,5-dimethyl piperidinium cation, C7H16N+]. The (3,5-DMP)3Sb2Br9 compound crystallizes in the triclinic crystal system (P1‾ space group), possessing a typical zero-dimensional (0D) structure with isolated face-sharing (Sb2Br9)3− bi-octahedral units encased by (3,5-DMP)+ organic cations. The isolated bi-octahedral units are distorted due to the strong stereochemical expression of the 5s2 lone pair on Sb3+ and intermolecular H-bonding between the organic moieties and inorganic clusters. The compound exhibited good thermal and environmental stability and possessed an indirect band gap of 2.92 eV. Upon 390 nm UV light excitation, the compound displayed a broad emission band centred at 555 nm, which was attributed to the self-trapped excitons (STEs) formed due to strong electron-phonon coupling in this compound. This study suggests the possibility of new types of 0D OIMHs by introducing different metal centers and bulky organic cations and provides a reference for the structure-property relationship in these compounds, thus, offering guidance for examining the structural evolution and improving their luminescent properties.

The synthesis, structures and characterizations of (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 crystals

Two new organic-inorganic hybrid crystals (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 were synthesized by solution method, and their basic physical properties, including structures, thermal stability analysis, UV–Vis diffuse reflectance absorption spectra and photoluminescent characteristic were characterized. The two crystals both crystallize in same monoclinic crystal system, but different P21/c and C2/c space group for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2, respectively. Their infrared, Raman and mass spectrometry were measured, with related characteristic peaks were identified. The Raman peaks at 249 and 88 cm−1 are ascribed to Cd-Cl stretching vibration and Cl-Cd-Cl deformation vibration, respectively. The mass spectra analysis confirm the existence of C5H12NO+ cation, [CdCl]+ and Na-(C5H12NO)2BiCl6·H4O2. A phase transition peak that respectively located at 378 and 403 K for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2 was detected by the synchronous thermal analysis, which is related with the loss of crystalline water in their structures. In addition, the maximum absorption peak at 230 and 240 nm, with corresponding band gap of 3.35 and 3.15 eV were fitted for (C5H12NO)4Cd3Cl10·2H2O and (C5H12NO)2BiCl6·H5O2, respectively. Furthermore, (C5H12NO)4Cd3Cl10·2H2O features a bluish white emission with the peak centering at 496 nm when it was excited at 380 nm by a Xenon lamp. This work extends the catalog of organic-inorganic hybrid metal halides and presents the potential application of (C5H12NO)4Cd3Cl10·2H2O in optical field.

Unveiling Chirality Transfer between Chiral Centers and Metal Halides in Chiral Organic-Inorganic Hybrid Metal Halides.

Chirality transfer refers to the process in which chiral cations compel the crystallization of the inorganic component into the Sohncke group. Enhancing the chirality of the inorganic component in chiral organic-inorganic hybrid metal halides (OIHMHs) through chirality transfer, aimed at improving chiroptical and spintronic properties, remains challenging due to the complexity of the underlying mechanism. To investigate this, we propose a novel concept─chirality transfer coefficient─as a means of quantifying the strength of chirality transfer in OIHMHs. A comparative study of OIHMHs with varying dimensionality, metal ions, and chiral centers was conducted to elucidate this mechanism. By analyzing factors such as hydrogen bonding, the number of chiral centers, dimensionality, helical geometry, and structural distortions, we found that chirality transfer is influenced by a combination of structural dimensions and the number of chiral centers. Importantly, our findings reveal that 0D, and 1D OIHMHs, particularly 1D with a zigzag chain configuration, exhibit stronger chirality transfer than their 2D counterparts. Moreover, in 2D OIHMHs, a reduction in the number of chiral centers enhances chirality transfer. However, no direct correlation was observed between chirality transfer and spin splitting. These insights contribute to a more comprehensive understanding of chirality transfer mechanisms and provide a strategic approach for enhancing the chirality transfer and associated physical properties in OIHMHs.

UV-Curing Resin-Assisted Facile Synthesis of Lead-Free Zero-Dimensional Organic–Inorganic Hybrid Metal Halide Quantum Dots for Light-Emitting Application

UV-Curing Resin-Assisted Facile Synthesis of Lead-Free Zero-Dimensional Organic–Inorganic Hybrid Metal Halide Quantum Dots for Light-Emitting Application

Sb3+ dopant triggered highly efficient emission in zero-dimensional organic-inorganic hybrid metal halides.

Hybrid luminescent metal halides have attracted considerable attention for their structural diversity and versatility in photonic applications. Herein, we fabricate Sb3+ doped organic-inorganic hybrid metal halides (DMA)2CsInCl6 (DMA = [CH3NH2CH3]+) single crystal. Under ultraviolet light excitation, the crystals yield bright green emission at 550 nm with near-unity photoluminescence quantum efficiency (PLQY), which is attributed to the strong electronegativity and ns2 lone pairs of Sb3+ dopants. Given the slender rod-shaped semblance, bright green emission, near-unity PLQY, and large Stokes shift, Sb3+-doped (DMA)2CsInCl6 allows the potential optical waveguide applications.

Toward an Ideal Light Source for Indoor Photosynthesis: Broadband Red Emission in Zero-Dimensional Hafnium-Based Metal Halide (TPP)2HfCl6·4C2H3N:Sb3.

With suitable electron-phonon coupling strength, a near-unity broadband photoluminescence quantum yield (PLQY) can be achieved in organic-inorganic hybrid metal halides (OIHMHs) via self-trapped exciton (STE) emission. However, it is still challenging to obtain high-quality red emission from OIHMHs with a desirable emission wavelength and high chemical stability, which hinders their practical application in high-performance displays, plant-growth lighting, and biomedical imaging. Herein, a series of hafnium-based zero-dimensional (TPP)2HfCl6·4C2H3N (TPP: tetraphenylphosphonium) single crystals with different Sb3+ doping levels are synthesized. The Sb3+-doped (TPP)2HfCl6·4C2H3N shows dual-band red emission with a full width at half-maximum of 178 nm and a high PLQY of 91.09%. This broad dual-band emission originates from dopant-induced extrinsic free excitons and STEs. Furthermore, (TPP)2HfCl6·4C2H3N:Sb3+ was employed as a luminescence converter in a light-emitting diode (LED) for plant growth regulation. A correlated color temperature of 4055 K and a color rendering index of 82.13 were achieved upon excitation of the LED at 365 nm. These results provide fundamental perspectives on the emission behavior of Sb3+-doped OIHMHs and illustrate their promise for use in plant-growth lighting.

Macroscopic Twisting of Chiral Metal Halide Single Crystals Driven by Thermo-Induced Topochemical Dehydration.

Dynamic twisting crystals, combining the features of dynamic crystals and twisting crystals, promise advanced applications in targeted drug delivery, biosensors, microrobots, and spiral optoelectronics. However, the determination of dynamic twisting crystals with specific directions remains a formidable challenge in practical applications. Herein, based on organic-inorganic hybrid metal halide (OIHMH) single crystals, we have realized the chirality-induced macroscopic twisting of single crystals driven by a thermo-induced topochemical dehydration reaction. These crystals exhibit molecular-chirality-induced twisting upon heating, along with reversals in their linear chiroptical circular dichroism and nonlinear chiroptical second harmonic generation circular dichroism. Such an induced twisting has been attributed to the alteration of the helical arrangement of chiral cation post-topochemical dehydration. The feasibility of tuning the macroscopic twisting of OIHMH single crystals and the switching in their linear and nonlinear chiroptical properties might open up new avenues for developing dynamic crystals for microactuating and optoelectronic applications.

Sn4+ Alloying and Chiral Incorporation into Tellurium Halides Triggering Tunable Luminescence Emission and Second-Harmonic Generation.

Recently, chiral organic-inorganic hybrid metal halides have attracted considerable interest as promising multifunctional materials, benefiting from their diverse structures and tunable photophysical properties. Herein, by introducing the chiral ligand methylbenzylamine (R-/S-MBA) and alloying Sn4+ cation, a series of tellurium-based halides R-/S-MBA2SnxTe1-xCl6 (x = 0, 0.125, 0.2, 0.365 and 0.54) with second-harmonic generation (SHG) effect and photoluminescence (PL) properties are successfully synthesized. Their optical bandgaps are determined to be 2.48-2.6 eV. Specifically, the introduction of chiral organic cations could break the structural symmetry and cause the tellurium halide to crystallize in the chiral space group. The incorporation of isovalent Sn4+ into the chiral host tellurium halides results in the increase in octahedral distortion, thereby promoting host intrinsic self-trapped emission that originates from the interconfigurational 3P0,1 → 1S0 transitions of Te4+. Consequently, the as-prepared Sn4+ doped halides, R-/S-MBA2SnxTe1-xCl6 (x = 0.365, 0.54), exhibit not only SHG response but also bright orange fluorescence. This study provides an effective strategy for designing chiral multifunctional materials.

Inorganic/organic sublattice roles in band edge photodynamics of isoelectronically substituted hybrid semiconductors

Zero-dimensional organic–inorganic hybrid metal halides are unique semiconductors with fruitful physical properties. Usually, only the inorganic polyhedrons dominate the band edge electronic and photophysical properties of such hybrid semiconductors, whereas the organic components mainly act as structure-stabilizing units. Herein, we study the electronic structures and photodynamics of isoelectronically Br-substituted (I) zero-dimensional organic–inorganic copper halide semiconductors (C9H14N)3Cu3(BrxI1−x)6. They are composed of both inorganic [Cu3(BrxI1−x)6]3− units and organic C9H14N+ skeletons. It is surprising to find that unlike usual organic–inorganic metal halides, although the heavily isoelectronic substitution of halogen atoms in the (C9H14N)3Cu3I6 crystal leads to significant shrinkage of the lattice, it does not remarkably alter the bandgap and luminescence peak owing to the site-projected density of states as revealed by the density functional theory calculation. The inorganic units dominate the valence band edge quantum states, whereas the organic skeletons dominate the conduction-band edge states. However, the isoelectronic substitution significantly lowers the symmetry of the crystal, and as a result, the quantum transition probability at the band edge increases first and decreases then with increasing concentration of substituting bromine atoms. The (C9H14N)3Cu3(BrxI1−x)6 crystals exhibit dual-band luminescence with large Stokes shift and near-unity quantum yield. It arises from the excitons trapped by two kinds of centers. The critical participation of the organic skeletons in the electronic structures and band edge photodynamics refresh our knowledge of their roles in the hybrid semiconductors.

A new zero-dimensional hybrid antimony halide of (C25H46N)2SbCl5 with dual-emission and high quantum-efficiency for light-emitting application

Zero-dimensional (0D) organic-inorganic hybrid metal halides (OIHMHs) have received extensive attention due to their excellent photoelectric properties. Herein, a new 0D OIHMH single crystal, (C25H46N)2SbCl5, has been synthesized by slow antisolvent diffusion. In this crystal structure, C25H46N+ (C25H46N+ = Cetyldimethylbenzylammonium cations) cations separated SbCl52− to form a 0D square pyramid structure. (C25H46N)2SbCl5 single crystals (SCs) manifest bright orange-yellow dual-emission bands at 472 and 616 nm, while having a high photoluminescent quantum yield of 97.5 %. The lifetime of high energy (HE) emission and low energy (LE) emission at room temperature is 9.73 ns and 4.61 μs, respectively. Based on lifetime differences and temperature-dependent spectra, the HE emission band is ascribed to singlet self-trapped excitons (STEs), while the LE emission band with a broad full width at half maxima of 136 nm can be attributed to triplet STEs. (C25H46N)2SbCl5 appeared anti-thermal quenching behavior. In accordance with the luminescence characteristics of (C25H46N)2SbCl5, a warm white light-emitting diode device was fabricated with the correlated color temperature of 3410 K, the relevant color coordinate of (0.41, 0.39) and the color rendering index of 95.1, demonstrating (C25H46N)2SbCl5 a promising phosphor for solid-state light-emitting application.

Unraveling the Role of Structural Topology on Chirality Transfer and Chiroptical Properties in Chiral Germanium Iodides.

Chiral hybrid organic-inorganic metal halides are highly promising chiroptoelectronic materials with potential applications in several fields, such as circularly polarized photodetectors, second-order nonlinear optics, and spin-selective devices. However, the ability of manipulating the chiroptical response and the chirality transfer from the organic ligands require one to shed light on structure-property correlations. Herein, we devised and prepared two novel Ge-based chiral hybrid organic-inorganic metal halides showing a different structural topology, namely, a 1D and a 2D arrangement, but composed of the same chemical building blocks: (R/S-ClMBA)3GeI5 and (R/S-ClMBA)2GeI4. Through a combined experimental and computational investigation on these samples, we discuss the impact of structural dimensionality on chiroptical properties, chirality transfer, and spin-splitting effects; also, we highlight the impact of structural distortions. The approach presented here paves the way for a solid understanding of the factors affecting the properties of chiral metal halides, thus allowing a future wise materials engineering.

Organic-Inorganic Hybrid Halide X-ray Scintillator with High Antiwater Stability.

In recent years, low-dimensional organic-inorganic hybrid metal halides have garnered significant attention for optoelectronic applications due to their exceptional photophysical properties, despite their persistent challenge of low stability. Addressing this challenge, our study introduces 1-[5-(trifluoromethyl)pyridin-2-yl]piperazinium (TFPP) as a cation, harvesting a novel one-dimensional hybrid cadmium-based halide semiconductor (TFPP)CdCl4, which exhibits intense blue-light emission upon UV excitation. Additionally, (TFPP)CdCl4 demonstrates a high scintillation performance under X-ray excitation, producing 16600 ± 500 photons MeV-1 and achieving a low detection limit of 0.891 μGyair s-1. Notably, (TFPP)CdCl4 showcases remarkable stability against water, intense light sources, heating, and corrosive environments, positioning it as a promising candidate for optoelectronic applications. Through a blend of experimental techniques and theoretical analyses, including density functional theory calculations, we elucidate the unique photophysical properties and structural stability of (TFPP)CdCl4. These findings significantly contribute to the understanding of low-dimensional hybrid halide semiconductors, offering valuable insights into their potential application in advanced optoelectronic devices and paving the way for further research in this field.

Multimode Luminesce Tailoring PMA4Na(In,Sb)Cl8 Organic-inorganic Hybrid Metal Halidevia Rigid Benzene Ring Induced Local Lattice Distortion.

Low dimensional organic-inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity-forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow-emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low-dimensional OIMHs single crystal with a PLQY as high as 88% was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity-forbidden transition by strong spin-orbit (SO) coupling and Jahn-Teller (JT) interaction. The as-prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1 → 1S0 transitions of Sb3+ in [SbCl6]3- octahedral caused by JT deformation. Moreover, wide-range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3- octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti-thermal quenching from 8 to 400 K owing to the suppression of non-radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti-counterfeiting and WLED applications.

Crown Ethers with Different Cavity Diameters Inhibit Ion Migration and Passivate Defects toward Efficient and Stable Lead Halide Perovskite Solar Cells.

Organic-inorganic hybrid metal halide perovskite solar cells have been considered as one of the most promising next-generation photovoltaic technologies. Nevertheless, perovskite defects and Li+ ionic migration will seriously affect the power conversion efficiency and stability of the formal device. Herein, we designed two crown ether derivatives (PC12 and PC15) with different cavity diameters, which selectively bind to different metal cations. It is found that PC15 in perovskite precursor solution can actively regulate the nucleation and crystallization processes and passivate the uncoordinated Pb2+ ions, while PC12 at the interface between the perovskite layer and hole-transporting layer can effectively inhibit the migration of Li+ ions and reduce nonradiative recombination losses. Therefore, PC12 and PC15 can act as "lubricant" and defect passivators, as well as inhibitors of ion migration, when they are synergistically applied at the surface and bulk of perovskite layer. Consequently, the optimized device achieved a champion efficiency of 24.8% with significantly improved humidity, thermal, and light stability.

Strain in Hybrid Organic-Inorganic Metal Halide Perovskites Microstructures by Numerical Simulations.

Hybrid organic-inorganic metal halide perovskites (HOIPs) are promising materials for optoelectronics applications. Their optical and electrical properties can be controlled by strain engineering, that results from application of local elastic deformation or deposition on pre-patterned substrates acquiring a conformal 3D shape. Most interesting, their mechanical properties depend on their crystal structure, composition and dimensionality. We explore by numerical simulations the deformation of a selection of HOIPs comprising a broad range of elastic properties. We consider an axial symmetry with the formation of microdomes on flakes. Radial and vertical forces are considered, finding that the radial force is more effective to obtain large deformation. Large vertical displacement and strain is obtained for HOIPs with low stiffness. The layered nature of HOIPs, that are formed by inorganic layers of different thickness and organic spacers, is also investigated, revealing a non-monotonous trend with the proportion of inorganic to organic part.

Anisotropic Electron-Phonon Interactions in 2D Lead-Halide Perovskites.

Two-dimensional (2D) hybrid organic-inorganic metal halide perovskites offer enhanced stability for perovskite-based applications. Their crystal structure's soft and ionic nature gives rise to strong interaction between charge carriers and ionic rearrangements. Here, we investigate the interaction of photogenerated electrons and ionic polarizations in single-crystal 2D perovskite butylammonium lead iodide (BAPI), varying the inorganic lamellae thickness in the 2D single crystals. We determine the directionality of the transition dipole moments (TDMs) of the relevant phonon modes (in the 0.3-3 THz range) by the angle- and polarization-dependent THz transmission measurements. We find a clear anisotropy of the in-plane photoconductivity, with a ∼10% reduction along the axis parallel with the transition dipole moment of the most strongly coupled phonon. Detailed calculations, based on Feynman polaron theory, indicate that the anisotropy originates from directional electron-phonon interactions.

Multifunctional Phosphor with High-Efficient Near-Infrared Emission Based on Antimony-Zinc Halides.

Metal halide-based broadband near-infrared (NIR) luminescent materials face problems such as complicated preparation, high cost, low photoluminescence quantum yield, and high excitation energy. Here, incorporating Sb3+ and Br- into (C20H20P)2ZnCl4 crystals allowed for the achievement of efficient broadband near-infrared emission under 400 nm excitation while maintaining satisfactory environmental and thermal stability. The compounds exhibit a broad range of emission bands from 550 to 1050 nm, with a photoluminescence quantum yield of 93.57%. This is a groundbreaking achievement for organic-inorganic hybrid metal halide NIR luminescent materials. The near-infrared emission is suggested to originate from [SbX5]2-, as supported by the femtosecond transient absorption spectra and density-functional theory calculations. This phosphor-based NIR LEDs successfully demonstrate potential applications in night vision, medical imaging, information encryption, and anticounterfeiting.