Excellent Photoluminescence Performance Research Articles

Realizing Near-Unity Photoluminescence Efficiency in Antimony-Doped Indium-Based Halides Induced by Strong Electron-Phonon Coupling.

Exploring a zero-dimensional (0D) hybrid halide with a large Stokes shift and efficient broad-band emission is highly desirable due to its enormous potential for solid-state lighting (SSL) application. However, it is still challenging to develop a highly emissive 0D hybrid halide with low toxicity and remarkable stability. Herein, we developed a novel indium-based metal halide A5In2Cl16·4H2O (A = doubly protonated 1,4-diaminobutane) whose inorganic octahedrons are completely isolated by the organic cations to form the 0D structure. Experimental and theoretical studies confirmed that Sb-doped A5In2Cl16·4H2O exhibits broad yellow emission with a photoluminescence quantum yield (PLQY) of up to 98%. The intense yellow emission can be attributed to the radiative recombination of triplet self-trapped excitons (STEs) in [SbCl6]3- octahedrons caused by the strong electron-phonon coupling. Benefiting from the excellent stability and photoluminescence performance, A5In2Cl16·4H2O:15%Sb was used as the yellow phosphor to prepare a white-light-emitting diode (WLED) device with a color rendering index of 87.8 and a luminous efficiency of up to 36.18 lm/W, demonstrating its potential in SSL applications. This work provides a guidance for developing environmentally friendly, efficient, and stable ultraviolet (UV)-excited broad-band emission materials.

Multifunctional BNT-based ferroelectric ceramics with large electrostrain and strong photoluminescence properties

The development of multifunctional materials with optical and electrical properties has become a research hotspot in recent years. In this work, multifunctional 0.935(Bi[Formula: see text]Na[Formula: see text])TiO3–0.065BaTiO3 (BNT–BT)-based ferroelectric ceramics doped with small amounts of CaMAlO4 ([Formula: see text], Ho) were prepared, and the effect of CaMAlO4 on the electrostrain and photoluminescence properties of the ceramics was studied. The results showed that the CaMAlO4 addition weakened the ferroelectric properties of the BNT–BT matrix, and promoted the improvement of the electrostrain performance. For samples doped with 1.5[Formula: see text]mol% CaMAlO4, the unipolar strain [Formula: see text] reached the largest values, which were 0.33% ([Formula: see text]) and 0.38% ([Formula: see text]) under an electric field of 70[Formula: see text]kV/cm, corresponding to a large signal [Formula: see text] ([Formula: see text]) of 471[Formula: see text]pm/V ([Formula: see text]) and 543[Formula: see text]pm/V ([Formula: see text]), respectively. In addition, due to the existing Dy[Formula: see text] and Ho[Formula: see text] luminescent ions, the modified samples exhibited excellent photoluminescence performance, which exhibited bright yellow emission ([Formula: see text]) and green emission [Formula: see text] under the blue excitation. Due to their multifunctional features, these materials have potential applications as “on-off” actuators, optical-electro integration and coupling devices.

Co(II)-coordination Complex: Fluorescence Performances and Combined with Taxotere-Hydrogels on Breast Cancer Treatment and Clinical Care.

In this study, a novel coordination polymer {Co2(Oaobtc)(bpe)(H2O)4]}n (1) was synthesized under hydrothermal conditions using a hybrid ligand synthesis method, where H4Oobtc represents 2,3,3'-tricarboxylate azobenzene, and bpe represents 1,2-bis(4-pyridyl)ethylene. The obtained CP1 was characterized by elemental analysis (EA), powder X-ray diffraction (PXRD), and thermal gravimetric analysis (TGA). Fluorescence testing confirmed the excellent photoluminescent performance of compound 1, indicating its potential as a cyan-emitting fluorescent material. Hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) are natural polysaccharides known for their biocompatibility. HA/CMCS hydrogels were synthesized using a chemical synthesis method, featuring a three-dimensional network structure with interconnected pores, and an average pore size of 314.75 ± 11.25μm. The characterization of the taxotere-loaded hydrogel was performed using infrared spectroscopy, confirming the effective encapsulation of the drug within the hydrogel. Utilizing taxotere as a model drug, a novel taxotere-loaded metal gel was synthesized, and its anticancer efficacy was evaluated. Furthermore, the influence of different pH levels on drug release rate was investigated. Finally, the encapsulation and release of taxotere in the hydrogel were studied using UV-visible spectroscopy.

0D and 1D-dimensional Cu(I)-based halides pyridyltriazoles basis: Synthesis, Structures, and photophysical properties

Three binuclear and two polymeric Cu(I) complexes namely, [Cu2(L1)2Cl2(PPh3)2] (1), [Cu2(L1)2Br2(PPh3)2] (2), [µ-L2(CuCl(PPh3)2)2]∙4MeOH (3), [CuBrL2(PPh3)]n (4) and [Cu2Cl2L2(PPh3)2]n (5) (3,5-bis(pyridin-4-yl)-1H-1,2,4-triazole (L1), 3,5-bis(pyridin-4-yl)-1H-1,2,4-triazole (L2) and 5-(pyridin-4-yl)-3-(pyridin-3-yl)-1H-1,2,4-triazole (L3)) were synthesized and structurally characterized. Binuclear complexes 1–3 show strong green luminescence in the crystals, exhibiting about 50 % photoluminescence quantum yields, while polymeric complexes show moderate emission in yellow region. The emission studies reveal that complexes 1–3 emit TADF from the 1(M + X)LCT state at room temperature because of their small singlet–triplet energy difference. Moreover complex 5 exhibited excellent stimuli-responsive photoluminescent performance in the solid state at room temperature.

Nano-scaled polyacrylonitrile for industrialization of nanofibers with photoluminescence and microbicide performance

Nanofibers are investigated to be superiorly applicable in different purposes such as drug delivery systems, air filters, wound dressing, water filters, and tissue engineering. Herein, polyacrylonitrile (PAN) is thermally treated for autocatalytic cyclization, to give optically active PAN-nanopolymer, which is subsequently applicable for preparation of nanofibers through solution blow spinning. Whereas, solution blow spinning is identified as a process for production of nanofibers characterized with high porosity and large surface area from a minimum amounts of polymer solution. The as-prepared nanofibers were shown with excellent photoluminescence and microbicide performance. According to rheological properties, to obtain spinnable PAN-nanopolymer, PAN (12.5–15% wt/vol, honey like solution, 678–834 mPa s), thermal treatment for 2–4 h must be performed, whereas, time prolongation resulted in PAN-nanopolymer gelling or rubbering. Size distribution of PAN-nanopolymer (12.5% wt/vol) is estimated (68.8 ± 22.2 nm), to reflect its compatibility for the production of carbon nanofibers with size distribution of 300–400 nm. Spectral mapping data for the photoluminescent emission showed that, PAN-nanopolymer were exhibited with two intense peaks at 498 nm and 545 nm, to affirm their superiority for production of fluorescent nanofibers. The microbial reduction % was estimated for carbon nanofibers prepared from PAN-nanopolymer (12.5% wt/vol) to be 61.5%, 71.4% and 81.9%, against S. aureus, E. coli and C. albicans, respectively. So, the prepared florescent carbon nanofibers can be potentially applicable in anti-infective therapy.

Fluorescence properties of novel deep-red phosphor LiMg4SbO7:Mn4+ with excellent quantum efficiency and color purity for warm white LEDs.

Red fluorescent materials have important application value in the background light and LED lighting fields of displays. In this work, a novel type of rare earth free deep-red phosphor LiMg4SbO7:Mn4+ was prepared successfully, and its crystal structure, microstructure, fluorescence spectrum, quantum yield, thermal stability, fluorescence lifetime, color coordinates and color purity were studied in detail. The excitation spectra of LiMg4SbO7:Mn4+ phosphors are located at 200-600 nm, which can be matched with ultraviolet, near-ultraviolet, and blue-light chips. The exciting result is that the LiMg4SbO7:0.002Mn4+ phosphor exhibits astonishing quantum efficiency, thermal stability and color purity. Finally, the developed LiMg4SbO7:Mn4+ and the yellow phosphor Y3Al5O12:Ce3+ (YAG:Ce3+) were mixed and coated on a blue light chip (460 nm) to produce a w-LED, which exhibited warm white luminescence with color coordinates of (0.3575, 0.3809), correlated colour temperature (CCT) of 4687 K, and color rendering index (CRI) of 83.6. It is reasonable to consider that LiMg4SbO7:Mn4+ phosphors with excellent photoluminescence performance have great application value in LED lighting fields.

Dual-mode luminous and afterglow Ca3Al2Ge3O12:Yb3+, Er3+ phosphors for anti-counterfeiting and fingerprint verification

Generally, traditional anti-counterfeiting fluorescent materials usually show a single peak under single wavelength excitation, which cannot meet the security of authentication information. Therefore, the simultaneous realization of multicolor, multiexcitation and multimodal luminescence properties remains a fascinating goal, especially in a single host. In this work, the sustained luminescent materials Ca3Al2Ge3O12:Yb3+, Er3+ (CAG:Yb3+, Er3+) were obtained, which can exhibit bright red and green luminescence with Er3+ ions under the 490 nm and near-infrared (980 nm) light excitation. The red emission dominates under the 980 nm laser irradiation, and the sample showed excellent photoluminescence (PL) and persistent luminescence (PersL) performance under the 490 nm irradiation, and the afterglow can exceed 6h. The up-conversion mechanism and emission properties of the phosphors were analytically studied, and some fluorescence-safe anti-counterfeiting patterns and multifunctional latent fingerprint (LFP) afterglow time imaging were designed as potential applications for anti-counterfeiting aspects and information storage.

Rubidium ions doping to improve the photoluminescence properties of Mn doped CsPbCl3 perovskite quantum dots

All-inorganic cesium lead halide CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have shown promising potential in current Mini/Micro-LED display applications due to their excellent photoluminescence performance. However, lead ions in PQDs are easily to leak owing to the unstable structure of PQDs, which hinders their commercial applications. Herein, we adopt Rb+ ions co-doping strategy to regulate the doping characteristics of Mn2+ ions in CsPbCl3 PQDs. The synthesized CsPbCl3:(Rb+, Mn2+) PQDs possess enhanced photoluminescence quantum yield of 71.1% due to the reduction of intrinsic defect states and Mn–Mn or Mn-traps in co-doped PQDs. Moreover, the white light emission of CsPb(Cl/Br)3:(Rb+, Mn2+) PQDs is achieved by anion exchange reaction and the constructed WLED exhibits the CIE coordinate of (0.33, 0.29) and the correlated color temperature of 5497 K. Benefiting from the substitution strategy, these doped CsPbX3 PQDs can be widely used as fluorescence conversion materials for the construction of Mini/Micro-LED.

Lemon juice-derived nitrogen-doped carbon quantum dots for highly sensitive and selective determination of ferrous ions and cell imaging

Ferrous ion (Fe2+) plays an important role in a large number of chemical and biological processes in living organisms. So, the accurate and rapid determination of Fe2+ in environmental and biological systems is an important issue. In this paper, N-CDs with uniform particle size, outstanding water solubility, favorable stability, high quantum yield (QY, 58.66 %) and excellent photoluminescence performance were prepared by one-step hydrothermal method using biomass lemon and ethylene diamine. The N-CDs showed a bright blue fluorescence under UV light. This new type of N-CDs can be used to effectively detect Fe2+ with high selectivity and sensitivity. It displayed a fine linear relationship in the range of 2–625 μΜ with the LOD of 0.063 μM under optimum conditions. The possible fluorescence quenching mechanism can be ascribed to the static quenching (SQ) and internal filtration effect (IFE) for Fe2+. More importantly, the optical imaging performance and cytotoxicity of N-CDs were also demonstrated. The results showed that N-CDs owned low cytotoxicity and glorious biocompatibility, and could be used as a biological imaging agent for labeling Hela cells. Therefore, this study possesses expansive application prospects in environmental monitoring and bioanalysis.

Carbon dot-based molecularly imprinted fluorescent nanopomegranate for selective detection of quinoline in coking wastewater

Quinoline, as a refractory and toxic organic pollutant in coking wastewater, causes great harm to the environment and human health even in trace amount. To realize the selective and sensitive detection of quinoline in coking wastewater, a novel molecularly imprinted fluorescent nanopomegranate with carbon dots (CDs) as seeds and fluorescence source (CD-MIP) was prepared, using quinoline as the template, and N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) as the monomer. The preparation and detection conditions of CD-MIP were systematically optimized. The structure and detection performance of CD-MIP were investigated in detail. The resulting CD-MIP exhibits excellent photoluminescence performance, high detection sensitivity, good selectivity and reproducibility towards quinoline. Under the optimized conditions, the fluorescence intensity of CD-MIP shows a satisfying linearity with quinoline concentration in the range of 20–200 mg/L with a detection limit of 6.7 mg/L. Owing to the existence of imprinted cavities that highly match with quinoline, a high imprinting factor (3.46) for CD-MIP was obtained. In addition, CD-MIP represents a greater affinity towards quinoline than towards other analogues, as well as an outstanding anti-interference capability. For trace analysis in real coking wastewater, CD-MIP also gives satisfactory results. Therefore, CD-MIP shows promising application in the selective detection of trace quinoline in wastewater.

Defect emission photoluminescence peak tuning by encapsulation of Au-NPs on ZnO mesoporous nanosponges

We synthesized Au nanoparticles (Au-NPs) encapsulated zinc oxide (ZnO:Au) nanosponges by the fraternization of ZnO nanoflowers with HCl (0–30 mM) concentrated colloidal Au-NPs at room temperature. The crystallite size (D) of mesoporous ZnO:Au decreased from 44 nm to 22 nm and the strain (τ) increased from 2.5 × 10−3 to 4.7 × 10−3 as the HCl concentration of colloidal Au-NPs increased from 0 mM to 30 mM. For elemental composition of ZnO:Au nanosponges, the STM-mapping confirmed the Au-NPs encapsulation on nanostructured ZnO. The bandgap, Eg, and the Urbach energy, Eu, of ZnO:Au decreased from 3.26 to 2.96 eV, and from 0.335 to 0.318 eV, as the colloidal Au-NPs increased from 0 mM to 30 mM, respectively. The structural and microstructure analysis showed the sponge like morphology along with wurtzite hexagonal structure of ZnO, which tuned the PL emission for the sensor selectivity. The visible emission of ZnO:Au nanosponges was greatly tuned from 600 nm to 500 nm with respect to the HCl diluted colloidal Au-NPs. The excellent photoluminescence (PL) performance of nanostructured ZnO:Au was attributed to the surface-plasmon-mediated sequential transfer of defect energy from ZnO to Au and electron transfer from excited Au to ZnO.

One-step hydrothermal synthesis of WS2 quantum dots as fluorescent sensor for sensitive and selective recognition of hemoglobin and cardiac biomarker myoglobin.

Transition metal dichalcogenide (TMD) dots exhibit excellent photoluminescence performance due to the quantum confinement effect and edge effect, and are extensively applied in electronic and optical devices, sensors, catalysis, and bioimaging. In this work, WS2 quantum dots (WS2 QDs) were prepared under a simple one-step hydrothermal method by optimizing the reaction conditions, and a quantum yield of 11.23% was achieved. The as-prepared WS2 QDs possess good photo-bleaching resistance, salt tolerance, and pH stability. The fluorescence investigations showed that the WS2 QDs acted as a highly efficient fluorescent sensor to detect hemoglobin (Hb) and cardiac biomarker myoglobin (Myo). The linear range was 1-600μg/mL for Hb and 0.01-120μg/mL for Myo, with detection limits as low as 260 and 7.6ng/mL, respectively. Importantly, the WS2 QDs were used to determine the Hb/Myo content in human blood/serum samples, with satisfactory results, indicating that this technique holds promise for application in clinical diagnosis associated with Hb/Myo levels. To the best of our knowledge, this is the first example of TMD QDs without any modification as a fluorescent sensor for detecting Hb and Myo simultaneously.

Rare-earth-free Mn4+-doped double perovskite structure phosphor for near ultraviolet excitation of WLED and plant cultivation

Phosphor covered light-emitting diodes (PC-LEDs) are wide applied to diverse fields due to its great advantages compared with the traditional light source. Therefrom, we report new rare-earth-free red-emitting Mn4+ doped Ca2InSbO6 and Sr2InSbO6 phosphors with excellent photoluminescence performance by the solid phase synthesis route. The resultant samples possess broad excitation band that is able to match well with current commercial near-ultraviolet (n-UV) chips and exhibit strong red emission at the excitation of n-UV light. Importantly, the quantum efficiency of the Mn4+-doped Sr2InSbO6 phosphor is measured to be 55.93%. Simultaneously, the quenching temperature of two phosphors is 403 and 438 K. Finally, the LED devices with strong white light are got and provided with low correlated color temperature (CCT) and good color-rendering index (CRI) values. And the emission spectrum overlaps with absorption curve of phytochrome protein Pfr. These results indicate the obtained sample can be a candidate for WLEDs and plant cultivation.

Rare-earth-free Sr2YSb1-xO6:xMn4+: Synthesis, structure, luminescence behavior, thermal stability, and applications

We report the rare-earth-free Sr2YSbO6 (SYS):Mn4+ phosphors with excellent photoluminescence performance for indoor illuminations. The phase structure, elemental composition, luminescence behavior, thermal stability, lifetime, color purity, and quantum yield (QY) were analyzed in detail. The resultant sample showed a broadband excitation wavelength in the range of 250–450 nm, and the optimal doping concentration was 0.5 mol%. Under the suitable excitation wavelength of 307 nm, the SYS:0.005Mn4+ phosphor emitted a deep-red emission with the Commission Internationale de I'Eclairage chromaticity coordinate of (0.708, 0.290) and a high color purity of 93.34%. The emission intensity was found to be about 59.45% at 423 K while the activation energy was 0.28 eV. Moreover, the lifetime and QY of the optimal sample were measured to be 641.58 µs and 38.37%, respectively. Eventually, the white lighting-emitting didoes (LEDs) exhibited a strong white light with good color-rendering index (CRI) and correlated color temperature (CCT) values. Besides that, the novel LED structure based on the SYS:0.005Mn4+-polydimethylsiloxane film could also emit a warm white region while the CRI and CCT values were measured to be about 81.39 and 3091 K.

Controllable preparation of boron nitride quantum dots with small size and strong blue photoluminescence

As a new type of quantum dots (QDs), boron nitride QDs (BNQDs), show promising potentials in disease diagnosis, fluorescence imaging and bio-sensing due to its good biocompatibility, low cytotoxicity and excellent photoluminescence performance. However, there are still challenges in preparing BNQDs with uniform and small size. In this paper, the BNQDs with uniform and small size have been prepared through a hydrothermal process with the exfoliated hexagonal boron nitride nanosheets (h-BNNSs) as precursor. The as-prepared BNQDs were characterized by transmission electron microscope (TEM), high-resolution TEM, fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis and photoluminescence spectra (PL) for morphology, surface functional groups, element composition and optical properties. The as-prepared BNQDs have uniform particle size distribution with an average lateral size of 1.65 nm, and a PL quantum yield of 2.49 %. In addition, the as-prepared BNQDs exhibit strong blue fluorescence under UV-vis (365 nm) irradiation and nanosecond luminescent decay. Furthermore, the effect of preparation parameters on the fluorescence performance of BNQDs was investigated which provides an optimal condition for the preparation of BNQDs with excellent fluorescence performance. Together with other advantages, such as excellent physical/chemical properties, good biocompatibility and low cytotoxicity, the as-prepared BNQDs have great potentials in medical diagnosis, biosensing, photoelectric devices and other fields in the future.

Structural design and evolution of a novel Bi3+-doped narrow-band emission blue phosphor with excellent photoluminescence performance for wide color gamut wLED

A series of novel garnet structure narrow-band blue emission phosphors Ca4HfGe3−ySiyO12:xBi3+(0 ≤x≤ 0.04, 0 ≤y≤ 0.9) with great color purity and enhanced thermal stability have been successfully developed and synthesized.

Enhancement of field-induced strain and bright upconversion luminescence in BNT-based multifunctional ceramics

In this work, a multifunctional lead-free (Bi0.5Na0.5)0.945Ba0.065Ti(1−x)(Fe0.5Sb0.5)xO3-0.005Er (BNBT-Er-xFS) ferroelectric material was prepared through the solid-state method, which has a large reversible field-induced strain of 0.465% (under an moderate electric field of 65 kV/cm) with a high normalized strain d33* (Smax/Emax) of 713 pm/V. Besides the excellent strain properties, this system also exhibits a bright green upconversion emission under excitation of 980 nm due to the luminescence characteristic of Er3+ ion. Moreover, the upconversion luminescence performance of BNBT-Er-xFS is enhanced with the (Fe0.5Sb0.5)4+ doping. At x = 0.0075, sample exhibited the strongest upconversion luminescence. As a multifunctional material, the BNBT-Er-xFS system is expected to be used in multifunctional electronic devices due to its excellent electrical and photoluminescence performance.

Novel synthesis of Mn: ZnSe@ZnS core–shell quantum dots based on photoinduced fluorescence enhancement

A novel Type-I Mn: ZnSe@ZnS core–shell quantum dots (QDs) was reported through a two-step procedure by using low-cost inorganic salts and naturalbiomacromolecule as raw materials. Based on a designed structure of L-cysteine-capped Mn: ZnSe QDs in aqueous media with the controllable surface, Mn: ZnSe@ZnS core–shell QDs were formed due to photoactive ions and defect curing under continuous constant light. The influences of experimental variables, including synthesis conditions of Mn: ZnSe QDs, different types and affecting factors of photo irradiation had been systematically investigated. Under the effect of photoinduced fluorescence enhancement, the photoluminescence (PL) intensity increases significantly by about 5–10 times after 1–3 h of UV irradiation. The position of the fluorescence peak was red-shifted by about 17 nm, emitting orange-red fluorescence. The photoluminescence quantum yield (PL QY) was markedly improved (up to 35%). The structure and morphology of Mn: ZnSe@ZnS core–shell QDs were also confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS) in detail. The mechanism of photoinduced fluorescence enhancement was attributed to L-cysteine allowed to release S2- to form a ZnS shell, and the passivated surface non-radiative relaxation centers of Mn: ZnSe@ZnS QDs was successfully synthesized with highuniform size, excellent photoluminescence performance, and good stability, all ofwhichmakethemgood potential candidates for white LEDs, and biological labels.

Doped Zero‐Dimensional Cesium Zinc Halides for High‐Efficiency Blue Light Emission

AbstractAll‐inorganic zero‐dimensional (0D) metal halides have recently received increasing attention due to their excellent photoluminescence (PL) performance and high stability. Herein, we present the successful doping of copper(I) into 0D Cs2ZnBr4. The incorporating of Cu+ cations enables the originally weakly luminescent Cs2ZnBr4 to exhibit an efficient blue emission centered at around 465 nm, with a high photoluminescence quantum yield (PLQY) of 65.3 %. Detailed spectral characterizations, including ultrafast transient absorption (TA) techniques, were carried out to investigate the effect of Cu+ dopants and the origin of blue emission in Cs2ZnBr4:Cu. To further study the role of the A‐site cation and halogen, A2ZnCl4:Cu (A=Cs, Rb) were also synthesized and found to generate intense sky‐blue emission (PLQY≈73.1 %). This work represents an effective strategy for the development of environmentally friendly, low‐cost and high‐efficiency blue‐emitting 0D all‐inorganic metal halides.

Doped Zero-Dimensional Cesium Zinc Halides for High-Efficiency Blue Light Emission.

All-inorganic zero-dimensional (0D) metal halides have recently received increasing attention due to their excellent photoluminescence (PL) performance and high stability. Herein, we present the successful doping of copper(I) into 0D Cs2 ZnBr4 . The incorporating of Cu+ cations enables the originally weakly luminescent Cs2 ZnBr4 to exhibit an efficient blue emission centered at around 465 nm, with a high photoluminescence quantum yield (PLQY) of 65.3 %. Detailed spectral characterizations, including ultrafast transient absorption (TA) techniques, were carried out to investigate the effect of Cu+ dopants and the origin of blue emission in Cs2 ZnBr4 :Cu. To further study the role of the A-site cation and halogen, A2 ZnCl4 :Cu (A=Cs, Rb) were also synthesized and found to generate intense sky-blue emission (PLQY≈73.1 %). This work represents an effective strategy for the development of environmentally friendly, low-cost and high-efficiency blue-emitting 0D all-inorganic metal halides.