Organic Metal Halide Research Articles

Large Cation Engineering in Organic Antimony Halides for Low‐Loss Active Waveguide

AbstractActive waveguides have attracted growing attention as a basic component of miniaturized and integrated photonic devices. However, most optical waveguide materials suffer from severe self‐absorption, which greatly increases the optical loss. Therefore, developing highly efficient red‐emitting materials with large Stokes shift and negligible self‐absorption is of great interest. Herein, this work proposes a strategy to achieve both large Stokes shifts and high photoluminescence quantum yield (PLQY) in organic metal halide via large cation engineering. Two zero‐dimensional antimony(III) chlorides, (TMA)2SbCl5 and (TMAA)2SbCl5, are designed and synthesized by screening the ligands with different cationic volumes. Experimental and theoretical results reveal that the large cation can promote the self‐trapped excitons emission and improve stability. Benefiting from the large Stokes shift (291 nm) and high PLQY (98.3%), the as‐prepared (TMAA)2SbCl5 microplate exhibits efficient active waveguide with low loss coefficient of 6.07 × 10−3 dB µm−1. This work not only develops a novel active waveguide material, but also provides insights into the role of organic cation, which will provide new inspiration for the exploitation of excellent luminescent metal halides and photonic devices.

Numerical investigation of toxic free perovskite solar cells for achieving high efficiency

Increasing efficiency, simple and inexpensive fabrication process and flexibility nature of organic metal halide perovskite (PVK) based solar cell has fascinated the researchers around the globe. However, Lead, a poisonous substance in PVK solar cell causes various issues which directly or indirectly impact the environment as well as the health of living things. It prevents the commercialization of PVK based solar cell. To overcome this, a number of lead-free perovskite solar cell has been designed and fabricated. But the conversion efficiency is still not up to par because of intrinsic losses. In order to improve the efficiency, a thorough theoretical investigation is required that can reveal the cause behind these losses. In this study a special PVK material named methylammonium tin iodide (MASnI3) is used in simulation platform to design a highly efficient organic lead-free solar cell. This study focuses on the optimization of active layer thickness, working temperature, capacitance-voltage (C-V), and impedance and defect density, as they plays major roles in determining the performance of toxic free organic PVK solar cell. The study confirms an high efficiency (η) of 24.22% at the optimized condition. Such high efficiency with an optimized structure can open a door for the commercialization of lead free PVK based solar cell.

Copper Organometallic Iodide Arrays for Efficient X-ray Imaging Scintillators.

Lead-free organic metal halide scintillators with low-dimensional electronic structures have demonstrated great potential in X-ray detection and imaging due to their excellent optoelectronic properties. Herein, the zero-dimensional organic copper halide (18-crown-6)2Na2(H2O)3Cu4I6 (CNCI) which exhibits negligible self-absorption and near-unity green-light emission was successfully deployed into X-ray imaging scintillators with outstanding X-ray sensitivity and imaging resolution. In particular, we fabricated a CNCI/polymer composite scintillator with an ultrahigh light yield of ∼109,000 photons/MeV, representing one of the highest values reported so far for scintillation materials. In addition, an ultralow detection limit of 59.4 nGy/s was achieved, which is approximately 92 times lower than the dosage for a standard medical examination. Moreover, the spatial imaging resolution of the CNCI scintillator was further improved by using a silicon template due to the wave-guiding of light through CNCI-filled pores. The pixelated CNCI-silicon array scintillation screen displays an impressive spatial resolution of 24.8 line pairs per millimeter (lp/mm) compared to the resolution of 16.3 lp/mm for CNCI-polymer film screens, representing the highest resolutions reported so far for organometallic-based X-ray imaging screens. This design represents a new approach to fabricating high-performance X-ray imaging scintillators based on organic metal halides for applications in medical radiography and security screening.

Nanostructuring of Rare-earth-based Single-Molecule Magnets as Long-range Ordered Arrays in the Framework of Organic Metal Halide Perovskites.

The nanostructuring of single-molecule magnets (SMMs) on substrates, in nanotubes and periodic frameworks is highly desired for the future magnetic recording devices. However, the ability to organize SMMs into long-range ordered arrays in these systems is still lacking. Here, we report the incorporation of magnetic (RECl2 (H2 O)6 )+ (RE=rare earths) molecular groups into the framework of an organic metal halide perovskite (OMHP)-(H2 dabco)CsCl3 . Intriguingly, we show the incorporated rare-earth groups self-organized into long-range ordered arrays that uniformly and periodically distributed in the A sites of OMHP. The ordered (RECl2 (H2 O)6 )+ groups serve as SMMs in the perovskite frameworks, exhibiting large effective magnetic moment, moderate magnetic anisotropy and two-step relaxation behavior. With the additional merit of great structural flexibility and multifunction of OMHPs, the preparation of the first SMMs@OMHP magnetic materials furthers the development of molecular spintronics.

Nanostructuring of Rare‐earth‐based Single‐Molecule Magnets as Long‐range Ordered Arrays in the Framework of Organic Metal Halide Perovskites

AbstractThe nanostructuring of single‐molecule magnets (SMMs) on substrates, in nanotubes and periodic frameworks is highly desired for the future magnetic recording devices. However, the ability to organize SMMs into long‐range ordered arrays in these systems is still lacking. Here, we report the incorporation of magnetic (RECl2(H2O)6)+ (RE=rare earths) molecular groups into the framework of an organic metal halide perovskite (OMHP)—(H2dabco)CsCl3. Intriguingly, we show the incorporated rare‐earth groups self‐organized into long‐range ordered arrays that uniformly and periodically distributed in the A sites of OMHP. The ordered (RECl2(H2O)6)+ groups serve as SMMs in the perovskite frameworks, exhibiting large effective magnetic moment, moderate magnetic anisotropy and two‐step relaxation behavior. With the additional merit of great structural flexibility and multifunction of OMHPs, the preparation of the first SMMs@OMHP magnetic materials furthers the development of molecular spintronics.

Efficient Red Light Emitting Diodes Based on a Zero‐Dimensional Organic Antimony Halide Hybrid (Adv. Mater. 9/2023)

Organic Metal Halide Hybrids Efficient electroluminescent devices can now be fabricated using solution-processed thin films based on 0D organic metal halide hybrids (OMHHs). In article number 2209417, Biwu Ma and co-workers develop a highly luminescent 0D OMHH containing organic semiconducting cations, which successfully addresses the issues of low conductivity and poor energy alignment of existing 0D OMHHs for electrically driven light-emitting diodes (LEDs).

Surface Effects on Anisotropic Photoluminescence in One‐Dimensional Organic Metal Halide Hybrids

1D organic metal halide hybrids (OMHHs) exhibit strongly anisotropic optical properties, highly efficient light emission, and large Stokes shift, holding promise for novel photodetection and lighting applications. However, the fundamental mechanisms governing their unique optical properties and in particular the impacts of surface effects are not understood. Herein, 1D C4N2H14PbBr4 by polarization‐dependent time‐averaged and time‐resolved photoluminescence (TRPL) spectroscopy, as a function of photoexcitation energy, is investigated. Surprisingly, it is found that the emission under photoexcitation polarized parallel to the 1D metal halide chains can be either stronger or weaker than that under perpendicular polarization, depending on the excitation energy. The excitation‐energy‐dependent anisotropic emission is attributed to fast surface recombination, supported by first‐principles calculations of optical absorption in this material. The fast surface recombination is directly confirmed by TRPL measurements, when the excitation is polarized parallel to the chains. The comprehensive studies provide a more complete picture for a deeper understanding of the optical anisotropy in 1D OMHHs.

Dynamic Photoresponsive Ultralong Phosphorescence from One-Dimensional Halide Microrods Toward Multilevel Information Storage

Open AccessCCS ChemistryRESEARCH ARTICLES18 Jan 2023Dynamic Photo-responsive Ultralong Phosphorescence from 1D Halide Microrods Towards Multi-level Information Storage Chang Xing, Bo Zhou, Dongpeng Yan and Wei-Hai Fang Chang Xing Google Scholar More articles by this author , Bo Zhou Google Scholar More articles by this author , Dongpeng Yan Google Scholar More articles by this author and Wei-Hai Fang Google Scholar More articles by this author https://doi.org/10.31635/ccschem.023.202202605 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Ultralong room temperature phosphorescence (RTP) has drawn much attention in fields such as optical imaging, sensors, information security, and so on. To meet the need of intelligent systems, the development of photoresponsive ultralong RTP materials is highly desirable, however it remains a challenge due to the lack of rational design strategies that can leverage RTP and photochromism effectively. Herein, we report a new type of onedimensional (1D) metal-organic halides (MOHs) that simultaneously exhibited dynamic ultralong RTP and photochromic optical waveguide with a large switching ratio, obvious visualization contrast, and robust reversibility. These properties facilitate future applications for multi-color photonic barcodes and optical logic gates. Moreover, benefiting from the color-time-space multi-dimensional tunable ultralong RTP, this 1D microrod displayed a multi-mode luminescent signal output, with significantly higher information storage capacity than typical fluorescent systems. Therefore, this work demonstrates a new 1D color-tunable optical waveguide and photo-responsive ultralong RTP based on molecular self-assembly of MOHs, and extends frontier photonic applications as multi-level data encryption and information storage at the micro/nanoscale. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentNot Yet AssignedSupporting Information Copyright & Permissions© 2023 Chinese Chemical Society Downloaded 0 times PDF downloadLoading ...

Efficient Red Light Emitting Diodes Based on a Zero-Dimensional Organic Antimony Halide Hybrid.

Zero-dimensional (0D) organic metal halide hybrids (OMHHs) have recently emerged as a new class of light emitting materials with exceptional color tunability. While near-unity photoluminescence quantum efficiencies (PLQEs) are routinely obtained for a large number of 0D OMHHs, it remains challenging to apply them as emitter for electrically driven light emitting diodes (LEDs), largely due to the low conductivity of wide bandgap organic cations. Here, the development of a new OMHH, triphenyl(9-phenyl-9H-carbazol-3-yl) phosphonium antimony bromide (TPPcarzSbBr4 ), as emitter for efficient LEDs, which consists of semiconducting organic cations (TPPcarz+ ) and light emitting antimony bromide anions (Sb2 Br8 2- ), is reported. By replacing one of the phenyl groups in a well-known tetraphenylphosphonium cation (TPP+ ) with an electroactive phenylcarbazole group, a semiconducting TPPcarz+ cation is developed for the preparation of red emitting 0D TPPcarzSbBr4 single crystals with a high PLQE of 93.8%. With solution processed TPPcarzSbBr4 thin films (PLQE of 86.1%) as light emitting layer, red LEDs are fabricated to exhibit an external quantum efficiency (EQE) of 5.12%, a peak luminance of 5957cd m-2 , and a current efficiency of 14.2cd A-1 , which are the best values reported to date for electroluminescence devices based on 0D OMHHs.

Recent advances in ultralong room-temperature phosphorescence materials based on metal–organic halides

Ultralong room-temperature phosphorescence (RTP) materials showing persistent luminescence have attracted much attention in the fields of information encryption, light-emitting diodes (LEDs), sensors, data storage, bioimaging, and so on.

One-dimensional organic metal halide nanoribbons with dual emission.

Organic metal halide hybrids with low-dimensional structures at the molecular level have received great attention recently for their exceptional structural tunability and unique photophysical properties. Here we report for the first time the synthesis and characterization of a one-dimensional (1D) organic metal halide hybrid, which contains metal halide nanoribbons with a width of three octahedral units. It is found that this material with a chemical formula C8H28N5Pb3Cl11 shows a dual emission with a photoluminescence quantum efficiency (PLQE) of around 25%. Photophysical studies and density functional theory (DFT) calculations suggest the coexisting of delocalized free excitons and localized self-trapped excitons in metal halide nanoribbons leading to the dual emission.

Synergistic passivation with multi-dentate 2,6-pyridinedicarboxylic acid for high-performance perovskite solar cells

The rare multi-dentate 2,6-pyridinedicarboxylic acid (2,6-PDA) is first applied for passivating the electronic defects in MAPbI3 film. Consequently, the PCE of the 2,6-PDA-passivated PSC with good stability is increased from 18.14% to 20.57%.

Designing an efficient lead-free perovskite solar cell with green-synthesized CuCrO2 and CeO2 as carrier transport materials.

With increased efficiency, simplicity in manufacturing, adaptability, and flexibility, solar cells constructed from organic metal halide perovskite (PVK) have recently attained great eminence. Lead, a poisonous substance, present in a conventional PVK impacts the environment and prevents commercialization. To deal with this issue, a number of toxicity-free PVK-constructed solar cells have been suggested. Nevertheless, inherent losses mean the efficiency conversion accomplished from these devices is inadequate. Therefore, a thorough theoretical investigation is indispensable for comprehending the losses to improve efficiency. The findings of a unique modelling method for organic lead-free solar cells, namely methylammonium tin iodide (MASnI3), are investigated to reach the maximum practical efficiencies. The layer pertinent to MASnI3 was constructed as a sandwich between a bio-synthesized electron transport layer (ETL) of CeO2 and a hole transport layer (HTL) of CuCrO2 in the designed perovskite solar cells (PSCs). In this study, the use of algae-synthesized Au in the back contacts has been proposed. To obtain the maximum performance, the devices are further analyzed and optimized for active layer thickness, working temperature, total and interface defect density analysis, impedance analysis (Z'-Z), and capacitance-voltage (C-V), respectively. An optimal conversion efficiency of 26.60% has been attained for an MASnI3-constructed PSC. The study findings may open the door to a lead-free PSC through improved conversion efficiencies.

Flexible Crystal Heterojunctions of Low-Dimensional Organic Metal Halides Enabling Color-Tunable Space-Resolved Optical Waveguides.

Molecular luminescent materials with optical waveguide have wide application prospects in light-emitting diodes, sensors, and logic gates. However, the majority of traditional optical waveguide systems are based on brittle molecular crystals, which limited the fabrication, transportation, storage, and adaptation of flexible devices under diverse application situations. To date, the design and synthesis of photofunctional materials with high flexibility, novel optical waveguide, and multi-port color-tunable emission in the same solid-state system remain an open challenge. Here, we have constructed new types of zero-dimensional organic metal halides (Au-4-dimethylaminopyridine [DMAP] and In-DMAP) with a rarely high elasticity and rather low loss coefficients for optical waveguide. Theoretical calculations on the intermolecular interactions showed that the high elasticity of 2 molecular crystalline materials was original from their herringbone structure and slip plane. Based on one-dimensional flexible microrods of 2 crystals and the 2-dimensional microplate of the Mn-DMAP, heterojunctions with multi-color and space-resolved optical waveguides have been fabricated. The formation mechanism of heterojunctions is based on the surface selective growth on account of the low lattice mismatch ratio between contacting crystal planes. Therefore, this work describes the first attempt to the design of metal-halide-based crystal heterojunctions with high flexibility and optical waveguide, expanding the prospects of traditional luminescent materials for smart optical devices, such as logic gates and multiplexers.

Synthesis, structure, and photoelectric properties of a novel zero-dimensional organic-inorganic hybrid perovskite (C6H9N2)2MnI4

Organic metal halides (OMHs) have attracted considerable attention in the field of materials science because of their low cost, easy structure adjustment, and excellent optoelectronic properties. In this study, we synthesized a new organic manganese halide single-crystal, viz. (C6H9N2)2MnI4. The single crystal belongs to the triclinic crystal system with a centrosymmetric P-1 space group. The optical bandgap (2.21 eV) of yellow (C6H9N2)2MnI4 is close to the narrow bandgap and has a wide excitation range, with an optimal excitation wavelength of 468 nm. Among reported tetrahedrally coordinated manganese-based OMHs luminescent materials, yellow-green fluorescence emission is rare. (C6H9N2)2MnI4 also has a high fluorescence quantum efficiency of 67% and a fluorescence lifetime of 44 μs, and can be used to fabricate a light-emitting diode (LED) device with a luminous efficiency of 9.61 lm/W, thus expanding the applications of organic manganese halide materials.

Situation and Perspectives on Tin-Based Perovskite Solar Cells

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.

Elucidating degradation mechanisms of mixed cation formamidinium-based perovskite solar cells under device operation conditions

Organic cation-based metal halide perovskites suffer from volatile material decomposition, and the approach to ensure stability under device operation conditions is still far from commercialization. Formamidinium (FA)-based perovskite solar cells (PeSCs) have been widely used, showing efficient power conversion efficiencies (PCEs). Despite the high PCE, FA-based perovskites lack stability, but the related degradation mechanisms are quite indefinite. In this study, we compared two different systems by introduction of inorganic and organic cations to increase FA-based perovskite stability. To relate the device operational stability, we exposed the mixed cation perovskite films under 1 sun illumination at 60 °C in ambient air and investigated the difference in the phase transition of inorganic-mixed and organic-mixed FA perovskites. Morphological and structural characterizations were collected to confirm that the type of the secondary cation plays a major role in determining whether perovskite degradation is triggered at the grain boundary or perovskite grain surfaces. Although the PCEs of the two device systems are similar, the degradation mechanisms varied significantly depending on the chemical properties of perovskite components.

Improving the Operational Stability of Near‐Infrared Quasi‐2D Perovskite Light‐Emitting Diodes by Cation Engineering

AbstractAlthough organic metal halide perovskite light‐emitting diodes (PeLEDs) have been developed rapidly in recent years, their commercialization and further applications are still hindered by ion migration‐induced inferior operational stability. Although the formation of a quasi‐2D structure is a well‐known solution that can efficiently suppress ion migration, the operation lifetime improvement is still limited. In this study, long‐chain phenylbutanammonium is used to replace the commonly used phenethylammonium as the L‐site cations. With large steric hindrance, ion migration inside the PeLEDs is effectively suppressed. Consequently, the PeLED with near‐infrared emission at 763 nm exhibited an operational lifetime (T90) of up to 5.3 h, which is 53‐fold higher than that of the control device. This study demonstrates the feasibility of significant stability improvement using a simple cation engineering strategy for PeLEDs.

CMOS-Compatible Optoelectronic Imagers

Silicon-based complementary metal oxide semiconductors have revolutionized the field of imaging, especially infrared imaging. Infrared focal plane array imagers are widely applied to night vision, haze imaging, food selection, semiconductor detection, and atmospheric pollutant detection. Over the past several decades, the CMOS integrated circuits modified by traditional bulk semiconductor materials as sensitivity sensors for optoelectronic imagers have been used for infrared imaging. However, traditional bulk semiconductor material-based infrared imagers are synthesized by complicated molecular beam epitaxy, and they are generally coupled with expensive flip-chip-integrated circuits. Hence, high costs and complicated fabrication processes limit the development and popularization of infrared imagers. Emerging materials, such as inorganic–organic metal halide perovskites, organic polymers, and colloidal quantum dots, have become the current focus point for preparing CMOS-compatible optoelectronic imagers, as they can effectively decrease costs. However, these emerging materials also have some problems in coupling with readout integrated circuits and uniformity, which can influence the quality of imagers. The method regarding coupling processes may become a key point for future research directions. In the current review, recent research progress on emerging materials for infrared imagers is summarized.

Intrinsic Ion Migration Dynamics in a One-Dimensional Organic Metal Halide Hybrid

Metal halide perovskites possess many physical properties amenable to optoelectronic applications, whereas the realization of these potentials has been hampered by their environmental and electronic instabilities. The morphological and molecular low dimensional perovskites and perovskite related materials have shown much promise in enhancing the chemical stability due to their unique molecular structures. Here we report on robust and reproducible four-terminal (4T) electrical measurements in a one-dimensional (1D) organic metal halide hybrid, (R)-{\alpha}-methylbenzylammonium lead triiodide ((R-{\alpha}-MBA)PbI3) made possible by its chemical stability. The results reveal a distinct intrinsic ion migration dynamic of single exponential, which underlies the unique 4T I-V characteristics. The dynamic is directly verified by real-time measurements of the transient ionic current. Our observations are consistent with photo-activation and field-assisted ion migration. The elucidated intrinsic ion dynamics may provide the physical basis for understanding and modelling the ubiquitous hysteresis in metal halides based electronic devices and new insights into the dynamics of ion migration in metal halide perovskites and hybrids in general.