Hybrid Organic-inorganic Metal Halide Research Articles

Tunable Afterglow and Self-Trapped Exciton Emissions in Zr (IV)-Based Organic-Inorganic Metal Halide Hybrids by Metal-Ion Doping.

Low-dimensional hybrid metal halide (LDHMH) materials have attracted considerable attention owing to their intriguing optical properties. To the best of the knowledge, this is the first study to successfully demonstrate both self-trap exciton (STE) and afterglow emissions in Zr-based LDHMH materials. The obtained pure (Ph3 S)2 ZrCl6 crystals showed near-ultraviolet phosphorescence and a green afterglow owing to the organic cation Ph3 S+ , while the Bi-doped and Sb-doped crystals exhibited both STE and afterglow emissions. However, the Te-doped crystals showed only a broad yellow STE emission owing to the [TeCl6 ]2- octahedron. In addition, all the crystals showed good stability. Notably, Sb-doped crystals produced white light, which can be adjusted between cold white and warm white using different excitations. Finally, this strategy for both STE and afterglow emissions can be applied to other LDHMH materials for optical applications.

Synthesizing and characterization of Lead Halide Perovskite Nanocrystals solar cells from reused car batteries

With the rapid increase of efficiency up to 23.7% during the past few years, hybrid organic-inorganic metal halide perovskite solar cells (PSCs) have become a research “hot spot” for many solar cell researchers. The perovskite materials show various advantages due to unique characteristics of perovskite materials, such as high photo-to-electric conversion efficiency, direct band gap, high light absorption coefficient, high charge-carrier mobility and long electron-hole electron transport distance. The low-cost fabrication techniques together with the high efficiency makes PSCs comparable with Si-based solar cells. This paper begins with the discussion of crystal structures of perovskite based on recent research findings. The following part of this paper discussion of synthetic process of lead iodide perovskite materials from lead-acid battery and Harvesting material from the anodes and cathodes of car battery; synthesizing PbI2 from the collected materials and compare with pure Lead iodide to know the absolute by XRD peak, depositing lead iodide perovskite nanocrystals. Efficient flexible PSCs are fabricated onto FTO glass substrate by a two-step coating method under ambient condition. By adjusting the concentration of precursor CH3NH3I (MAI), the morphology and thickness of perovskite layer is effectively tailored, according to SEM analysis and using TiO2 as electron transport layer instead of ZnO and CuI instead of spiro-OMeTAD as hole transport layer.

Achieving a Highly Stable Perovskite Photodetector with a Long Lifetime Fabricated via an All-Vacuum Deposition Process

Hybrid organic-inorganic metal halide perovskites (HOIP) have become a promising visible light sensing material due to their excellent optoelectronic characteristics. Despite the superiority, overcoming the stability issue for commercialization remains a challenge. Herein, an extremely stable photodetector was demonstrated and fabricated with Cs0.06FA0.94Pb(I0.68Br0.32)3 perovskite by an all-vacuum process. The photodetector achieves a current density up to 1.793 × 10-2 A cm-2 under standard one sun solar illumination while maintaining a current density as low as 8.627 × 10-10 A cm-2 at zero bias voltage. The linear dynamic range (LDR) and transient voltage response were found to be comparable to the silicon-based photodetector (Newport 818-SL). Most importantly, the device maintains 95% of the initial performance after 960 h of incessant exposure under one sun solar illumination. The achievements of these outstanding results contributed to the all-vacuum deposition process delivering a film with high stability and good uniformity, which in turn delays the degradation process. The degradation mechanism is further investigated by impedance spectroscopy to reveal the charge dynamics in the photodetector under different exposure times.

Implications of Electron Transport Layer and Back Metal Contact Variations in Tin–Lead Perovskite Solar Cells Assessed by Spectroscopic Ellipsometry and External Quantum Efficiency

The structural and optical properties of hybrid organic-inorganic metal halide perovskite solar cells are measured by spectroscopic ellipsometry to reveal an optically distinct interfacial layer among the back contact metal, charge transport, and absorber layers. Understanding how this interfacial layer impacts performance is essential for developing higher performing solar cells. This interfacial layer is modeled by Bruggeman effective medium approximations (EMAs) to contain perovskite, C60, BCP, and metal. External quantum efficiency (EQE) simulations that consider scattering, electronic losses, and the formation of nonparallel interfaces are created with input derived from ellipsometry structural-optical models and compared with experimental EQE to estimate optical losses. This nonplanar interface causes optical losses in short circuit current density (JSC) of up to 1.2 mA cm-2. A study of glass/C60/SnO2/Ag or Cu and glass/C60/BCP/Ag film stacks shows that C60 and BCP mix, but replacing BCP with SnO2 can prevent mixing between the ETLs to prevent contact between C60 and back contact metal and enable the formation of a planar interface between ETLs and back contact metals.

Intermolecular arrangement facilitated broadband blue emission in group-12 metal (Zn, Cd) hybrid halides and their applications

Various fluorescent organic materials are widely known for their potential applications in light-emitting diodes, organic lasers, anti-counterfeiting and bio-imaging. However, poor emission efficiency and stability issues limit their usability. Here we report the syntheses, crystal and electronic structures, and optical characterizations of two new hybrid organic-inorganic group 12 halides, (P-xd)ZnCl4 and (P-xd)CdCl4 (where (P-xd) = p-xylylenediammonium). Single crystals of both compounds can be conveniently synthesized by solution chemistry methods from their low-cost, low toxicity and easily available precursors. (P-xd)ZnCl4 possesses a crystal structure featuring alternating layers of organic cations and completely separated anionic [ZnCl4]2- tetrahedral units of zero-dimensional (0D) connectivity. In contrast, (P-xd)CdCl4 adopts similar layering of organic cations sandwiched between perovskite sheets of two-dimensional (2D) connectivity, which are formed by corner-sharing anionic [CdCl6]4- octahedral units. The structural, optical, and electronic studies suggest that the incorporation of organic and inorganic structural units into a hybrid structure improves its blue emission efficiency with nearly 23 times and 4 times higher photoluminescence quantum yield (PLQY) values in (P-xd)ZnCl4 and (P-xd)CdCl4, respectively, as compared to the organic precursor. Notably, PLQY of 23% for (P-xd)ZnCl4 is the highest reported to date for Zn-based hybrid organic-inorganic metal halides, where emission originates from the organic component. Both (P-xd)ZnCl4 and (P-xd)CdCl4 demonstrate considerably improved air-, thermal- and photostability, which suggest their suitability for potential practical applications such as fingerprint detection and solid-state lighting.

One-Dimensional Chiral Copper Iodide Chain-Like Structure Cu4 I4 (R/S-3-quinuclidinol)3 with Near-Unity Photoluminescence Quantum Yield and Efficient Circularly Polarized Luminescence.

Chiral organic-inorganic hybrid metal halide materials have shown great potential for circularly polarized luminescence (CPL) related applications for their tunable structures and efficient emissions. Here, this work combines the highly emissive Cu4 I4 cubane cluster with chiral organic ligand R/S-3-quinuclidinol, to construct a new type of 1D Cu-I chains, namely Cu4 I4 (R/S-3-quinuclidinol)3 , crystallizing in noncentrosymmetric monoclinic P21 space group. These enantiomorphic hybrids exhibit long-term stability and show bright yellow emission with a photoluminescence quantum yield (PLQY) close to 100%. Due to the successful chirality transfer from the chiral ligands to the inorganic backbone, the enantiomers show intriguing chiroptical properties, such as circular dichroism (CD) and CPL. The CPL dissymmetry factor (glum ) is measured to be ≈4×10-3 . Time-resolved photoluminescence (PL) measurements show long averaged decay lifetime up to 10 µs. The structural details within the Cu4 I4 reveal the chiral nature of these basic building units, which are significantly different than in the achiral case. This discovery provides new structural insights for the design of high performance CPL materials and their applications in light emitting devices.

Organic–Inorganic Hybrid Alkali Copper Iodides for Bright Emission across the Visible Spectrum

Organic–inorganic hybrid metal halides are well known for their structural flexibility and high photoluminescence quantum yield (PLQY), showing great potential for optical applications. In this work, we demonstrate the synthesis of a series of alkali copper(I) iodide (ACuI)-based (A = Na, K, Rb, and Cs) organic–inorganic hybrid materials with different structures and emission peaks by adjustment of the alkali atoms and organic molecules. These compounds possess strong PL with emission peaks in the range of 530–660 nm, the highest PLQY of 91% was achieved for KCuI2(C4H8OS)2, and their different emissions originate from distinct charge-transfer processes. Green, yellow, and red light-emitting diodes (LEDs) can be fabricated by using these materials, and a white LED based on all-copper iodide phosphors is demonstrated with a high color rendering index of 93 by utilizing a mixture of blue-emissive Cs3Cu2I5 and yellow-emissive Rb2Cu2I4(C4H8OS)3 powders. This work provides a new strategy for the development of hybrid copper halides with composition-tunable structures and high performance and demonstrates that this series of (ACuI)-based compounds could be candidates for emission applications, including lighting or display.

Moisture-Induced reversible structure conversion of Zero-Dimensional organic cuprous bromide hybrids for multiple photoluminescent anti-Counterfeiting, information encryption and rewritable luminescent paper

With social development and the technology advancement, the demand for high-security photoluminescence (PL) anti-counterfeiting and information encryption materials is increasing constantly. Herein, two organic cuprous bromide hybrids, namely (TPA)CuBr2 and (TPA)2Cu4Br6, with variable coordination geometries were synthesized via a facile solution method. (TPA)CuBr2 shines bright cyan emission with a photoluminescence quantum efficiency (PLQE) of 81 % under 254 nm excitation, while (TPA)2Cu4Br6 exhibits orange emission with a PLQE of 95 % upon 365 nm irradiation. Interestingly, a reversible structural conversion could be triggered by water or heat between (TPA)CuBr2 and (TPA)2Cu4Br6, accompanied by a back-and-forth emission color change between cyan and orange under its respective excitation. The emission mechanism of above two compounds was investigated, and the results show that they stem from self-trapped excitons emission. Such PL color switching under the external stimuli of water, heat and different excitation wavelengths enables us to construct a series of anti-counterfeiting and information encryption scenarios. In addition, the rewritable PL paper based on (TPA)CuBr2 with water as ink is realized. These two compounds not only provide a good way to modulate zero-dimensional Cu(I)-based metal halide with highly efficient emission, but also a new example to develop multifunctional applications by organic–inorganic hybrid metal halides.

(C5N2H14)GeBr4: A 2D Organic Germanium Bromide Perovskite with Strong Orange Photoluminescence Properties

Hybrid organic-inorganic metal halide (OIMH) perovskites are regarded as potential photoluminescent (PL) materials and have attracted intensive attention. Here, we select 1-methylpiperazine as an organic component and successfully obtain a two-dimensional (2D) Ge-based OIMH perovskite, (1-mpz)GeBr4. It features a 2D layered structure composed of distorted [GeBr6]4- octahedra with organic (C5H14N2)2+ located between the layers. (1-mpz)GeBr4 exhibits strong orange color under ultraviolet (UV) light and possesses good PL stability for over 2 months. The photoluminescence quantum efficiency is measured to be 7.15% at room temperature, which is the largest among all reported low-dimensional Ge-based perovskites. Experimental measurements, combined with first-principles calculations, reveal that its PL property is attributed to self-trapped excitons (STEs) from [GeBr6]4- groups. From the deduced structure-property relationship, Ge-based OIMH PL perovskites with good stability and high PL efficiency can be expected.

Linear optical afterglow and nonlinear optical harmonic generation from chiral tin(IV) halides: the role of lattice distortions.

The striking chemical variability of hybrid organic-inorganic metal halides (HOMHs) endows them with fascinating optoelectronic properties. The inorganic skeletons of HOMHs are often flexible and their lattice deformations could serve as an effective factor for enabling the functionalities of HOMHs. Here, the linear and nonlinear optical properties of zero-dimensional (0D) tin(IV) halides have been tuned by structural distortion facilitated by the chiral amines. Enantiopure α-methylbenzyl ammoniums (XMBA, X = Cl, F) effectively transfer their chirality to the inorganic scaffolds when forming the tin(IV) halides, which enables polar arrangements in their crystals and leads to outstanding second-order nonlinear optical performances. In contrast, the racemic mixture of R- and S-FMBA results in the formation of HOMHs with room temperature phosphorescence. The lower lattice deformation in (rac-FMBA)2SnCl6 restrains the non-radiative decay from electron-phonon coupling and facilitates the photoluminescence. Meanwhile, the marked π-π interaction stabilizes the T1 state for phosphorescent emission. These distinct linear and nonlinear optical properties denote the important role that the lattice distortion plays in tuning the optical properties of low-dimensional HOMHs, and offer a promising perspective of 0D tin(IV) halides for applications in optoelectronic materials and devices.

Bromination of organic spacer impacts on the structural arrangement, phase transitions, and optical and electrical properties of a hybrid halide compound:[(CH3)3N(CH2)3Br]2PdBr4

Understanding the structure and arrangement of organic inorganic hybrid metal halides and their contribution to physical properties remains a challenging topic.

Thermosalient effect of a naphthalene diimide and tetrachlorocobaltate hybrid and changes of color and magnetic properties by ammonia vapor.

An organic-inorganic hybrid metal halide (OIMH), namely the electron-deficient naphthalene diimide (NDI) and [CoCl4]2- hybrid (1), showed potential as a sensor for ammonia and amines, in addition to magnetic changes upon vapochromism. Crystal 1 exhibited thermosalient behavior such as leaping and movement, at around 130 °C, which could be explained to be associated with the removal of water molecules from the crystal lattice as shown by TGA and DSC. Compound 1 changed from green to black within 5 minutes when exposed to ammonia vapor, which was attributed to the radical formation in the NDI moiety as evidenced by ESR, and this phenomenon was preserved even when other mono- and di-alkylamines were applied. The exposure of 1 to ammonia resulted in a subsequent color alteration, progressing from black to a gradually dark orange after one day (1_NH3_1 day). This transformation was concomitant with the formation of [Co(NH3)6]3+ from [CoCl4]2-, leading to a modification of the magnetic properties from paramagnetic Co(II) (S = 3/2) to diamagnetic Co(III) (S = 0). Based on these findings, compound 1 represents the first example of an OIMH that exhibits thermosalient behaviour, color change, and magnetic conversion upon exposure to ammonia.

(CH3)2NH2]2PdBr4, a layered hybrid halide perovskite semiconductor with improved optical and electrical properties.

Inspired by the success of three-dimensional hybrid perovskites (CH3NH3)PbX3 (X = Cl, Br, I), two-dimensional (2D) organic-inorganic hybrid metal halides have drawn immense attention due to their highly tunable physical properties. Moreover, although 3D hybrid perovskite materials have been reported, the development of new organic-inorganic hybrid semiconductors is still an area in urgent need of investigation. Here, we used the dimethylammonium cation to construct a palladium-based halide perovskite material [(CH3)2NH2]2PdBr4 with a 2D layered structure. This layered perovskite undergoes one endothermic peak at 415 K corresponding to melting of the organic molecule. The thermal stability of the compound is up to about 500 K. The activation energy and conduction mechanisms are discussed, and the optical study shows a gap energy equal to 2.5 eV. The electrical AC conductivity is in the order of 10-4 Ω-1 cm-1, which confirms the semiconductor character of this material and indicates its importance in the optoelectronic domain.

Second harmonic generation from symmetry breaking stimulated by mixed organic cations in zero-dimensional hybrid metal halides.

Mixing cations with different chemical properties to induce the generation of asymmetric structures is a new approach for tuning the optical properties of hybrid organic-inorganic metal halides (HOIMHs). In this study, zero-dimensional (C9N3H15)(C9H13SO)MBr6 (M = Bi/Sb, [C9N3H15]2+ = [(C4N2H10)(C5NH5)]2+ and [C9H14SO]+ = [CH3(C6H4)OS(CH3)2]+) are synthesized. Two different cations cause both compounds to crystallize in the polar space group P212121, thus resulting in significant phase matchable second harmonic generation under a 1064 nm laser excitation. Thus, (C9N3H15)(C9H13SO)BiBr6 and (C9N3H15)(C9H13SO)SbBr6 exhibit intensities that are approximately 1.8 and 1.7 times that of KH2PO4, respectively. The results of density functional theory calculations show that both (C9N3H15)(C9H13SO)BiBr6 and (C9N3H15)(C9H13SO)SbBr6 exhibit direct bandgaps of 2.95 and 2.81 eV, respectively. Additionally, because of the distortion of the inorganic octahedra, (C9N3H15)(C9H13SO)SbBr6 exhibited bright yellow emission at room temperature, which is attributed to ns2 fluorescence emission. We believe that the symmetry of the HOIMH crystal structure can be broken by introducing spatially differentiated bifunctional organic cations, which consequently enables even-order nonlinear activities.

Lead-free hybrid indium perovskites with near-unity PLQY and white light emission using an Sb3+doping strategy

A series of new Sb3+ doped-(DETA)InCl6 organic–inorganic hybrid metal halide single crystals were synthesized. The PLQY of single crystals doped with 10% Sb was up to 100%, and white light emission was achieved when the Sb doping amount was 0.005%.

Regulation and application of organic luminescence from low-dimensional organic–inorganic hybrid metal halides

In this review, the organic luminescence properties of low-dimensional organic–inorganic hybrid metal halides (LDMHs) are summarized, with emphasis on the mechanism, regulating strategy and applications of organic luminescence in LDMHs.

Regulation strategy of white emission from organic–inorganic hybrid metal halide perovskites

In this review, the structure, photophysical properties, and white-light mechanism of organic–inorganic hybrid metal halide perovskites with white emission are summarized, with an emphasis on the adjustment strategy for white-light performance.

Halogen-regulating induced reversible high-temperature dielectric and thermal transitions in novel layered organic-inorganic hybrid semiconducting crystals.

Organic-inorganic hybrid metal halides for high-temperature phase transition have become increasingly popular owing to their wide operating temperature range in practical applications, e.g., energy storage, permittivity switches and opto-electronic devices. This paper describes the subtle assembly of two new hybrid perovskite crystals, [Cl-C6H4-(CH2)2NH3]2CdX4 (X = Br 1; Cl 2), undergoing high-T reversible phase transformations around 335 K/356 K. Differential scanning calorimetry (DSC), differential thermal analysis (DTA) and VT PXRD tests uncover their reversible first-order phase transition behaviors. Furthermore, the compounds exhibit switchable dielectricity near T, making them potential dielectric switching materials. Hirshfeld surface analysis well discloses a distinct difference in hydrogen-bonding interaction between 1 and 2. UV spectra and computational analysis demonstrate that the compounds are a type of direct-band-gap semiconductor. This research will contribute an effective approach to the structure and development of multifunctional molecular hybrid crystals.

Zero-dimensional organic-inorganic hybrid manganese bromide with coexistence of dielectric-thermal double switches and efficient photoluminescence.

Zero-dimensional (0D) hybrid metal halides have attracted much attention due to their rich composition, excellent optical stability, large exciton binding energy, etc. Photoelectric switchable multifunctional materials can integrate multiple physical properties (e.g., ferroelectricity, photoluminescence, magnetic, etc.) into one device and are widely used in many fields such as smart switches, sensors, etc. However, multifunctional materials with thermal energy storage, stimulant dielectric response, and light-emitting properties are rarely reported. Here, we synthesized a new organic-inorganic hybrid metal halide single crystal [TEMA]2MnBr4 (1) (TEMA+ = triethylmethylammonium). Compound 1 undergoes a reversible phase transition at a high temperature of 344/316 K, having a large thermal hysteresis of 28 K and exhibits high stability dielectric switching characteristics near the phase transition temperature. The single crystal exhibits green emission at 513 nm under UV excitation, originating from the 4T1g(G) → 6A1g(S) transition of Mn2+ ions. Excitingly, this single crystal's photoluminescence quantum yield (PLQY) is as high as 80.78%. This work provides a strategy for the development of organic-inorganic hybrid optoelectronic multifunctional materials with high-efficient light emission and switchable dielectric properties.

Solution Synthesis, Photophysical Properties and Photoelectric Application of Zero-dimensional Organic-inorganic Hybrid Metal Halide

Solution Synthesis, Photophysical Properties and Photoelectric Application of Zero-dimensional Organic-inorganic Hybrid Metal Halide