Search Results (18)

Developing lead-free organic-inorganic hybrid metal halides with strong light-harvesting capabilities and superior stability, while precisely tuning their crystalline phases and electronic structures, remains a key challenge in optoelectronics. Herein, we report a neutral iodine-induced structural transition from a 1D chain-like (C₆H₁₁NH₃)₂SbI₅ architecture to a 0D dimeric (C₆H₁₁NH₃)₃[Sb₂I₉]·I₂ supramolecular host-guest complex. This transformation is achieved via a controlled solution-cooling crystallization process, yielding high-quality bulk single crystals. Crystallographic analysis reveals that N–H···I hydrogen-bonding networks stabilize the organic cations, while halogen bonding interactions anchor the I₂ guests within the lattice cavities of the [Sb₂I₉]³⁻ dimeric host. Experimental characterizations, including XRD, TGA, and XPS, confirm the high phase purity and thermal stability of the (C₆H₁₁NH₃)₃[Sb₂I₉]·I₂ hybrid and determine its electronic band structure. To further elucidate the underlying mechanisms, theoretical calculations were performed, revealing that strong sp-orbital hybridization yields a high absorption coefficient. The associated dimensional transition narrows the direct optical bandgap to 1.46 eV, approaching the Shockley-Queisser limit and demonstrating strong potential for visible-light harvesting. This work elucidates the role of supramolecular host-guest interactions in modulating the lattice evolution of lead-free antimony-based materials, presenting halogen guest engineering as an effective approach for optoelectronic material design. Full article

Organic–inorganic hybrid metal halides (OIMHs), especially zero-dimensional (0D) ones, have been recognized as an excellent class of luminescent materials due to their structural diversity and tunable emission properties. In this work, using the environmentally friendly Zn(II) ion as the central metal and 1,4,7,10-tetraazacyclododecane (Cyclen) as the organic component, we successfully synthesized a novel OIMH, (H₃Cyclen)(ZnBr₄)·Br·H₂O. Single-crystal X-ray diffraction analysis reveals that (H₃Cyclen)(ZnBr₄)·Br·H₂O possesses a 0D structure, in which the [ZnBr₄]²⁻ tetrahedra are uniformly separated by the organic amine cations. This structural feature is expected to enhance the material’s stability and optimize its optoelectronic properties. Under UV lamp irradiation, (H₃Cyclen)(ZnBr₄)·Br·H₂O emits bright blue-green light. Therefore, we systematically investigated its luminescence properties. The emission mechanism was further elucidated using UV–vis absorption spectroscopy and DFT calculations. Finally, (H₃Cyclen)(ZnBr₄)·Br·H₂O was employed as a luminescent material to fabricate a white light-emitting diode (WLED), demonstrating its potential as an excellent phosphor material. Full article

Transition-metal Co²⁺ ions in halide systems are generally regarded as inefficient emitters due to rapid nonradiative relaxation of their d-d excited states. Here, we prepared two zero-dimensional (0D) organic-inorganic hybrid cobalt halides, benzyl triphenyl phosphonium bromide cobalt ((BTP)₂CoBr₄) and triphenyl phosphonium bromide cobalt ((PPh₃)₂CoBr₄), composed of [CoBr₄]²⁻ tetrahedra embedded in distinct organic frameworks. Upon Pb²⁺ incorporation, both compounds exhibit visible photoluminescence composed mainly of two emission bands centered at approximately 450 and 500 nm, with decay lifetimes on the nanosecond timescale. The emission at 450 nm originates from d-d transitions associated with short-range Co-Co ferromagnetic (FM) interactions, whereas the 500 nm emission can be attributed to donor-acceptor pair (DAP) transitions involving Co and Pb. At low temperatures, an additional broadband emission centered at ~620 nm emerges in Pb²⁺-doped (PPh₃)₂CoBr₄, with lifetimes reaching the microsecond scale, while such emission is not observed in (BTP)₂CoBr₄. Low-temperature lattice contraction in the PPh₃ framework further shortens the Co-Co distance, thereby enhancing short-range FM interactions and leading to the formation of a magnetic bipolaron for emission. Overall, this work reveals the role of organic ligand structure and dopant modulation in regulating the Co-centered excited states, providing deeper insight into the interactions between cobalt ions and organic ligands in low-dimensional halide systems. Full article

Two-dimensional (2D) metal halide perovskites have attracted considerable interest for their markedly improved environmental stability and versatile compositional tunability compared to their three-dimensional (3D) counterparts. Nevertheless, the anisotropic charge transport caused by insulating organic spacers often leads to inefficient charge transport and limiting device performance. Precise control over crystallographic orientation, particularly achieving vertical alignment of the inorganic layers, is essential to facilitate out-of-plane charge transport and enhance device efficiency. This review systematically summarizes recent advances in understanding and controlling the crystallographic orientation of 2D perovskites, emphasizing manipulating strategies such as processing optimization, composition engineering, spacer design, solvent selection, and additive assistance to promote vertical alignment of inorganic layers and improve interlayer charge transport. We also discuss the influence of phase distribution, quantum well width, and crystal growth kinetics on device performance. Finally, we outline prevailing challenges and future opportunities for achieving the ideal microstructure and high-efficiency 2D perovskite solar cells. Full article

Two-dimensional (2D) metal-halide perovskites with highly efficient room-temperature phosphorescence (RTP) are rare due to their complex structures and intricate intermolecular interactions. In this study, by varying the alkyl chain length in organic amines, we synthesized two 2D metal-halide perovskites, namely 4-POMACC and 4-POEACC, both of which exhibit significant RTP emission. Notably, 4-POMACC demonstrates a stronger green RTP emission with a significantly longer lifetime (254 ms) and a higher photoluminescence quantum yield (9.5%) compared to 4-POEACC. A thorough investigation of structural and optical properties reveals that shorter alkyl chains can enhance the optical performance due to reduced molecular vibrations and more effective exciton recombination. Computational calculations further show that the smaller energy gap between S₁ and T_n in 4-POMA facilitates intersystem crossing, thereby improving RTP performance. Based on their remarkable phosphorescence properties, we demonstrated their applications in information encryption. This work offers a novel design strategy that could inspire the development of next-generation RTP materials. Full article

Stimulus-responsive inorganic–organic hybrid metal halides (IOMHs) have shown great potential in applications such as sensing and anti-counterfeiting. IOMHs can undergo a variety of structural changes when triggered by humidity; however, relevant reports of structural dimensionality change from zero dimension (0D) to one dimension (1D) are rare. This study investigates the synthesis, structure, and properties of two antimony-based IOMHs, namely 0D-(Mp)₃SbCl₆·MeCN and 1D-(Mp)₂SbCl₅ (Mp = protonated morpholine; MeCN = acetonitrile). Photophysical characterizations show that (Mp)₃SbCl₆·MeCN, when being excited at 375 nm, exhibits typical self-trapped exciton triplet state broad-band emission, with a peak at 620 nm and a quantum yield as high as 75.06%. Under humid conditions, the 0D structure of (Mp)₃SbCl₆·MeCN undergoes a phase transition, leading to the 1D structure of (Mp)₂SbCl₅. This transition is accompanied by fluorescence quenching. X-ray powder diffraction, Raman spectroscopy, and thermogravimetric analysis confirm the phase transition process and its reversibility. Based on the high contrast of fluorescence before and after phase transition, (Mp)₃SbCl₆·MeCN is demonstrated as an ideal material for fluorescence water sensing, capable of detecting trace amounts of water in tetrahydrofuran with a detection limit of 0.2% v/v. Full article

The application of metal–organic frameworks (MOFs) has attracted increasing attention in organic synthesis. The modification of MOFs can efficiently tailor the structure and improve the property for meeting ongoing demand in various applications, such as the alteration of gas adsorption and separation, catalytic activity, stability, and sustainability or reusability. In this study, carboxyethylsilanetriol (CEST) disodium salt was used as a dual-functional ligand for modified Al-MIL-53 to fabricate CEST-functionalized Al-MIL-53 samples through a hydrothermal reaction of aluminum nitrate, terephthalic acid, and CEST disodium salt by varying the molar ratio of CEST to terephthalic acid and keeping a constant molar ratio of Al³⁺/-COOH of 1:1. The structure, composition, morphology, pore feature, and stability were characterized by XRD, different spectroscopies, electron microscopy, N₂ physisorption, and thermogravimetric analysis. With increasing CEST content, CEST-Al-MIL-53 still preserves an Al-MIL-53-like structure, but the microstructure changed compared with pure Al-MIL-53 due to the integration of CEST. Such a CEST-Al-MIL-53 was used as the support to load Pd particles and afford a catalyst Pd/CEST-Al-MIL-53 for Suzuki–Miyaura C-C cross-coupling reaction of aryl halides and phenylboronic acid under basic conditions. The resulting Pd/CEST-Al-MIL-53 showed a high catalytic activity compared with Pd/Al-MIL-53, due to the nanofibrous structure of silicon species-integrated CEST-Al-MIL-53. The nanofiber microstructure undergoes a remarkable transformation into intricate 3D cross-networks during catalytic reaction, which enables the leachable Pd particles to orientally redeposit and inlay into these networks as the monodisperse spheres and thereby effectively preventing Pd particles from aggregation and leaching, therefore demonstrating a high catalytic performance, long-term stability, and enhanced reusability. Obviously, the integration of CEST into MOFs can effectively prevent the leaching of active Pd species and ensure the re-deposition during catalysis. Moreover, catalytic performance strongly depended on catalyst dosage, temperature, time, solvent, and the type of the substituted group on benzene ring. This work further extends the catalytic application of hybrid metal–organic frameworks. Full article

Lead-free Mn²⁺-based metal halide materials are now being considered as clean candidates for backlight displays and lights due to the d–d transition, diverse components, and environmental friendliness. Therefore, efficient and stable Mn²⁺-based metal halide phosphors are in great demand for practical applications. In this work, adopting the mixed-ligand strategy, a series of [(CH₃)₄N]_2−x[(C₂H₅)₄N]_xMnCl₄ phosphors were synthesized by mechanochemical process. With the increase molar ratio of (CH₃)₄N/(C₂H₅)₄N, the phase of phosphors is transformed from orthorhombic to tetragonal. Compared to [(CH₃)₄N]₂MnCl₄ and [(C₂H₅)₄N]₂MnCl₄ phosphors, the mixed-ligand strategy significantly boosts the green emission intensity of Mn²⁺-based metal halide phosphors. The obtained [(CH₃)₄N][(C₂H₅)₄N]MnCl₄ phosphors exhibit a high photoluminescence quantum yield (PLQY) of 83.78% under 450 nm excitation, which is attributed to the modulation of the adjacent [MnCl₄]₂- distance by using the different chain length of organic cations, effectively suppressing non-radiative recombination. Additionally, the [(CH₃)₄N][(C₂H₅)₄N]MnCl₄ phosphors exhibit a green emission at 516 nm, narrow full width at half-maximum (FWHM) of 45.53 nm, and good thermal stability. The constructed white light-emitting diode (WLED) device exhibits a wide color gamut of 108.3% National Television System Committee, demonstrating the suitability of the [(CH₃)₄N][(C₂H₅)₄N]MnCl₄ phosphors as a green emitter for WLED displays and lightings. This work provides a new way to modulate the PL performance of manganese-based metal halides for application in the optoelectronic field. Full article

Organometal halide perovskites have achieved great success in solution-processed photovoltaics. The explorations quickly expanded into other optoelectronic applications, including light-emitting diodes, lasers, and photodetectors. An in-depth analysis of the special scale effects is essential to understand the working mechanisms of devices and optimize the materials towards an enhanced performance. Generally speaking, organometal halide perovskites can be classified in two ways. By controlling the morphological dimensionality, 2D perovskite nanoplatelets, 1D perovskite nanowires, and 0D perovskite quantum dots have been studied. Using appropriate organic and inorganic components, low-dimensional organic–inorganic metal halide hybrids with 2D, quasi-2D, 1D, and 0D structures at the molecular level have been developed and studied. This provides opportunities to investigate the scale-dependent properties. Here, we present the progress on the characteristics of scale effects in organometal halide perovskites in these two classifications, with a focus on carrier diffusion, excitonic features, and defect properties. Full article

Organic–inorganic metal halide perovskite (OIMHP) has emerged as a promising material for solar cell application due to their outstanding optoelectronics properties. The perovskite-based solar cell (PSC) demonstrates a significant enhancement in efficiency of more than 20%, with a certified efficiency rating of 23.13%. Considering both the Shockley limit and bandgap, there exists a substantial potential for further efficiency improvement. However, stability remains a significant obstacle in the commercialization of these devices. Compared to organic carrier transport layers (CTLs), inorganic material such as ZnO, TiO₂, SnO₂, and NiO_X offer the advantage of being deposited using atomic layer deposition (ALD), which in turn improves the efficiency and stability of the device. In this study, methylammonium lead iodide (MAPbI₃)-based cells with inorganic CTL layers of SnO₂ and NiO_X are simulated using SCAPS-1D software. The cell structure configuration comprises ITO/SnO₂/CH₃NH₃PbI₃/NiO_X/Back contact where SnO₂ and NiO_X act as ETL and HTL, respectively, while ITO is a transparent front-end electrode. Detailed investigation is carried out into the influence of various factors, including MAPbI₃ layer size, the thickness of CTLs, operating temperature parasitic resistance, light intensity, bulk defects, and interfacial defects on the performance parameters. We found that the defects in layers and interface junctions greatly influence the performance parameter of the cell, which is eliminated through an ALD deposition approach. The optimum size of the MAPbI₃ layer and CTL was found to be 400 nm and 50 nm, respectively. At the optimized configuration, the PSC demonstrates an efficiency of 22.13%, short circuit current (JSC) of 20.93 mA/m², open circuit voltage (V_OC) of 1.32 V, and fill factor (FF) of 70.86%. Full article

In this paper, the synthesis and crystal structure of pyrazine-2,5-diyldimethanol (pyzdmH2, C₆H₈N₂O₂), a new symmetric water-soluble N,O-chelating tetra-dentate organic ligand, is reported and an environmentally friendly method is used to synthesize coordination compounds in water under ambient conditions, from the reaction of pyzdmH2 with the halide salts of Cu(II), Zn(II), Hg(II) and Cd(II): {[Cu(pyzdmH2)_0.5(µ-Br)(Br)(H₂O)]·H₂O}_n 1, {[Zn₂(pyzdmH2)(µ-Cl)(Cl)₃(H₂O)]·H₂O}_n 2, [Hg₂(pyzdmH2)_0.5(µ-Cl)₂(Cl)₂]_n 3, {[Cd₂(pyzdmH2)(µ-Cl)₄]·H₂O}_n 4, and {[Cd₂(pyzdmH2)(µ-Br)₄]·H₂O}_n 5. Single-crystal X-ray diffraction analysis reveals that 1–3 are 1D coordination polymers and 4 and 5 are 3D coordination networks, all constructed by bridging pyrazine-2,5-diyldimethanol and halogen ions. The hydroxyl groups in the organic linker extend the 1D chains to non-covalent 3D networks. In all non-covalent and covalent 3D networks, water molecules are trapped by strong hydrogen bond interactions. Supramolecular analysis reveals strong O-H···O, O-H···N, O-H···X, and weak C-H···O, C-H···X (X = Cl, Br) hydrogen bonds, as well as π-π(pyrazine ring), metal-halogen···π(pyrazine ring), and O-H···ring(5-membered chelate ring) interactions. In addition, X···O weak halogen bonds are present in 1–5 (X = Cl and Br). Full article

Layered magnetic metal-organic frameworks (MOFs) are an emerging class of materials that can combine the advantages of both MOFs and 2D magnetic crystals. The recent discovery of large coercivity and long-range magnetic ordering up to 515 K in a layered MOF of general formula MCl₂(pyz)₂ (M = transition metal, pyz = pyrazine) offers an exciting versatile platform to achieve high-T_C magnetism at the 2D limit. In this work, we investigate the exfoliation feasibility down to the monolayer of VCl₂(pyz)₂ and CrCl₂(pyz)₂ by means of first-principles calculations. We explore their structural, electronic, magnetic and vibrational properties, as well as the effect of halide substitution. Then, we provide a full analysis of the spin-phonon coupling (SPC) in both 2D derivatives. Our calculations reveal a low SPC and thermal evolution of the magnetic exchange interactions and single-ion anisotropy mainly governed by low-frequency phonon modes. Finally, we provide chemical insights to improve the performance of these magnetic 2D MOFs based on the effective manipulation of the phonon modes that can present a major impact on their magnetic properties. Full article

Recently zero-dimensional (0-D) inorganic–organic metal halides (IOMHs) have become a promising class of optoelectronic materials. Herein, we report a new photoluminescent (PL) 0-D antimony(III)-based IOMH single crystal, namely [H₂BPZ][SbCl₅]·H₂O (BPZ = benzylpiperazine). Photophysical characterizations indicate that [H₂BPZ][SbCl₅]·H₂O exhibits singlet/triplet dual-band emission. Density functional theory (DFT) calculations suggest that [H₂BPZ][SbCl₅]·H₂O has the large energy difference between singlet and triplet states, which might induce the dual emission in this compound. Temperature-dependent PL spectra analyses suggest the soft lattice and strong electron–phonon coupling in this compound. Thermogravimetric analysis shows that the water molecules in the lattice of the title crystal could be removed by thermal treatment, giving rise to a dehydrated phase of [H₂BPZ][SbCl₅]. Interestingly, such structural transformation is accompanied by a reversible PL emission transition between red light (630 nm, dehydrated phase) and yellow light (595 nm, water-containing phase). When being exposed to an environment with 77% relative humidity, the emission color of the dehydrated phase was able to change from red to yellow within 20 s, and the red emission could be restored after reheating. The red to yellow emission switching could be achieved in acetone with water concentration as low as 0.2 vol%. The reversible PL transition phenomenon makes [H₂BPZ][SbCl₅]·H₂O a potential material for luminescent water-sensing. Full article

Perovskite solar cells have become the current research focus because of their high conversion efficiency and other advantages; however, the toxicity of lead used in them has raised environmental concerns. Tin-based perovskite materials have become the most promising alternative materials for perovskite solar cells because of their relatively low toxicity, suitable band gap and relatively higher energy conversion efficiency than perovskite materials based on other elements. In this article, the status of this rapidly growing field, authors’ output and cooperation, hot research topics, important references and the development trends of tin-based perovskite solar cells are identified and visualized using CiteSpace software. The main research fields are found to be optical properties, 3D–2D perovskite and perovskite solar cell conduction band materials. The mixed organic metal halide perovskite solar cell and the CsSnI₃ semiconductor are identified as emerging trends for tin-based perovskite solar cells. Such contents in this article highlight the key points in the wide field of literature so it can be understood efficiently. Full article

Metal halide perovskites have become a research highlight in the optoelectronic field due to their excellent properties. The perovskite light-emitting diodes (PeLEDs) have achieved great improvement in performance in recent years, and the construction of quasi-2D perovskites by incorporating large-size organic cations is an effective strategy for fabricating efficient PeLEDs. Here, we incorporate the fluorine meta-substituted phenethylammonium bromide (m-FPEABr) into CsPbBr₃ to prepare quasi-2D perovskite films for efficient PeLEDs, and study the effect of fluorine substitution on regulating the crystallization kinetics and phase distribution of the quasi-2D perovskites. It is found that m-FPEABr allows the transformation of low-n phases to high-n phases during the annealing process, leading to the suppression of n = 1 phase and increasing higher-n phases with improved crystallinity. The rational phase distribution results in the formation of multiple quantum wells (MQWs) in the m-FPEABr based films. The carrier dynamics study reveals that the resultant MQWs enable rapid energy funneling from low-n phases to emission centers. As a result, the green PeLEDs achieve a peak external quantum efficiency of 16.66% at the luminance of 1279 cd m⁻². Our study demonstrates that the fluorinated organic cations would provide a facile and effective approach to developing high-performance PeLEDs. Full article