- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Broadband Emission in Hybrid Organic–Inorganic Halides of Group 12 Metals
摘要： We report syntheses, crystal and electronic structures, and characterization of three new hybrid organic?inorganic halides (R)ZnBr3(DMSO), (R)2CdBr4·DMSO, and (R)CdI3(DMSO) (where (R) = C6(CH3)5CH2N(CH3)3, and DMSO = dimethyl sulfoxide). The compounds can be conveniently prepared as single crystals and bulk polycrystalline powders using a DMSO?methanol solvent system. On the basis of the single-crystal X-ray diffraction results carried out at room temperature and 100 K, all compounds have zero-dimensional (0D) crystal structures featuring alternating layers of bulky organic cations and molecular inorganic anions based on a tetrahedral coordination around group 12 metal cations. The presence of discrete molecular building blocks in the 0D structures results in localized charges and tunable room-temperature light emission, including white light for (R)ZnBr3(DMSO), bluish-white light for (R)2CdBr4·DMSO, and green for (R)CdI3(DMSO). The highest photoluminescence quantum yield (PLQY) value of 3.07% was measured for (R)ZnBr3(DMSO), which emits cold white light based on the calculated correlated color temperature (CCT) of 11,044 K. All compounds exhibit fast photoluminescence lifetimes on the timescale of tens of nanoseconds, consistent with the fast luminescence decay observed in π-conjugated organic molecules. Temperature dependence photoluminescence study showed the appearance of additional peaks around 550 nm, resulting from the organic salt emission. Density functional theory calculations show that the incorporation of both the low-gap aromatic molecule R and the relatively electropositive Zn and Cd metals can lead to exciton localization at the aromatic molecular cations, which act as luminescence centers.
关键词： zero-dimensional structures,broadband emission,group 12 metals,exciton localization,photoluminescence quantum yield,hybrid organic?inorganic halides
更新于2025-09-23 15:23:52
-
Effect of phase transition on SiO2-coated CsPbBr3/Cs4PbBr6 quantum dots: Air-stability and quantum efficiency improvement
摘要： To develop white light-emitting diodes (WLEDs) with wide color gamut for displays, compared with nitride-based phosphors and traditional core-shell quantum dots (QDs) such as CdSe, InP, CuInS2, all-inorganic perovskite QDs CsPbX3 (X = Cl, Br, I) were more promising luminescent materials due to tunable wavelength, narrow emission spectrum and high quantum efficiency. However, when QDs were made into solid form (powders or films), poor air-stability and drastic decrease of quantum efficiency would be observed in CsPbBr3. These drawbacks would restrict their practical applications. To resolve these issues, in this paper, we proposed a new concept that zero-dimensional perovskite QDs powders Cs4PbBr6 with outstanding quantum efficiency and long lifetime up to three months could be successfully prepared via silica-coated method and crystal phase transition in low-temperature synthesis. This phenomenon of phase transition would be discussed in detail and the quantum efficiency could be improved from 31.41% to 45.87%. Moreover, green LEDs with high color purity of 92% and luminous efficiency of 88.59 lm/W could also be achieved by using this material. Therefore, our proposed perovskite QDs powders Cs4PbBr6 had extreme potential for displays applications.
关键词： Zero-dimensional perovskite quantum dots,Phase transition mechanisms
更新于2025-09-23 15:19:57
-
Zero-dimensional hybrid iodobismuthate derivatives: from structure study to photovoltaic application
摘要： The quest for lead-free light-absorbing perovskite materials has long been the target of researchers to make the ‘star’ material friendly to the commercial market. After a summary of different lead-free solar absorbers, we demonstrate a zero-dimensional iodobismuthate (MA)3[BiI6] ? 3MACl (MA: CH3NH3) featuring isolated hexaiodobismuthate (III) anions in the crystal analysis. The unexpectedly formed material was made via an orthogonal solvent permeation method and the decomposition of the guest solvent. We compare the BiI6 3- containing compound with a series of more common iodobismuthates, especially the dinuclear Bi2I9 3- in terms of dimensionalities via single-crystal diffraction and DFT calculations, respectively. An undocumented second-order phase transition was found between 190 K and 160 K for the dimeric MA3Bi2I9. The photovoltaic device from a thermally reorganized polycrystalline film of (MA)3[BiI6] ? 3MACl, which resembled the structure of (MA)3[Bi2I9] gave a power conversion efficiency of 1.09%.
关键词： photovoltaic,iodobismuthate,perovskite,zero-dimensional,lead-free
更新于2025-09-23 15:19:57
-
Air-Stable, Lead-Free Zero-Dimensional Mixed Bismuth-Antimony Perovskite Single Crystals with Ultrabroad Band Emission
摘要： Lead-free zero-dimensional (0D) organic-inorganic metal halide perovskites have recently attracted increasing attention for their excellent photoluminescence properties and chemical stability. Here, we report the synthesis and characterization of an air-stable 0D mixed metal halide perovskite (C8NH12)4Bi0.57Sb0.43Br7.H2O, in which individual [BiBr6]3- and [SbBr6]3- octahedral units are completely isolated and surrounded by the large organic cation C8H12N+. Upon photoexcitation, the bulk crystals exhibit ultrabroad band emission ranging from 400 to 850 nm, which originates from both free excitons and self-trapped excitons. This is the first example of 0D perovskites with broadband emission spanning the entire visible spectrum. In addition, (C8NH12)4Bi0.57Sb0.43Br7.H2O exhibits excellent humidity and light stability. These findings present a new direction towards the design of environmentally-friendly, high-performance 0D perovskite light emitters.
关键词： lead-free,bismuth,antimony,photoluminescence,zero-dimensional perovskites
更新于2025-09-19 17:15:36