An official website of the United States government
Abstract Copper(I) halides are emerging as attractive alternatives to lead halide perovskites for optical and electronic applications. However, blue‐emitting all‐inorganic copper(I) halides suffer from poor stability and lack of tunability of their photoluminescence (PL) properties. Here, the preparation of silver(I) halides A2AgX3(A = Rb, Cs; X = Cl, Br, I) through solid‐state synthesis is reported. In contrast to the Cu(I) analogs, A2AgX3are broad‐band emitters sensitive to A and X site substitutions. First‐principle calculations show that defect‐bound excitons are responsible for the observed main PL peaks in Rb2AgX3and that self‐trapped excitons (STEs) contribute to a minor PL peak in Rb2AgBr3. This is in sharp contrast to Rb2CuX3, in which the PL is dominated by the emission by STEs. Moreover, the replacement of Cu(I) with Ag(I) in A2AgX3significantly improves photostability and stability in the air under ambient conditions, which enables their consideration for practical applications. Thus, luminescent inks based on A2AgX3are prepared and successfully used in anti‐counterfeiting applications. The excellent light emission properties, significantly improved stability, simple preparation method, and tunable light emission properties demonstrated by A2AgX3suggest that silver(I) halides may be attractive alternatives to toxic lead halide perovskites and unstable copper(I) halides for optical applications.
more »
« less
Stimuli‐responsive photoluminescent copper(I) halides for scintillation, anticounterfeiting, and light‐emitting diode applications
Abstract Highly sensitive stimuli‐responsive luminescent materials are crucial for applications in optical sensing, security, and anticounterfeiting. Here, we report two zero‐dimensional (0D) copper(I) halides, (TEP)2Cu2Br4, (TEP)2Cu4Br6, and 1D (TEP)3Ag6Br9, which are comprised of isolated [Cu2Br4]2−, [Cu4Br6]2−, and [Ag6Br9]3−polyanions, respectively, separated by TEP+(tetraethylphosphonium [TEP]) cations. (TEP)2Cu2Br4and (TEP)2Cu4Br6demonstrate greenish‐white and orange‐red emissions, respectively, with near unity photoluminescence quantum yields, while (TEP)3Ag6Br9is a poor light emitter. Optical spectroscopy measurements and density‐functional theory calculations reveal that photoemissions of these compounds originate from self‐trapped excitons due to the excited‐state distortions in the copper(I) halide units. Crystals of Cu(I) halides are radioluminescence active at room temperature under both X‐ and γ‐rays exposure. The light yields up to 15,800 ph/MeV under 662 keV γ‐rays of137Cs suggesting their potential for scintillation applications. Remarkably, (TEP)2Cu2Br4and (TEP)2Cu4Br6are interconvertible through chemical stimuli or reverse crystallization. In addition, both compounds demonstrate luminescence on‐off switching upon thermal stimuli. The sensitivity of (TEP)2Cu2Br4and (TEP)2Cu4Br6to the chemical and thermal stimuli coupled with their ultrabright emission allows their consideration for applications such as solid‐state lighting, sensing, information storage, and anticounterfeiting.
more »
« less
- Award ID(s):
- 2045490
- PAR ID:
- 10510189
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Aggregate
- Volume:
- 5
- Issue:
- 5
- ISSN:
- 2692-4560
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract All‐inorganic metal halides such as Cs4PbX6and CsPbX3(X = Cl, Br, and I) are attracting global attention owing to their promise in optoelectronic applications. However, the presence of the toxic heavy metal lead (Pb) in these materials is a major concern. Here, a family of nontoxic high‐efficiency blue‐emitting all‐inorganic halides Rb2CuX3(X = Br and Cl) is reported; the compounds exhibit 1D crystal structures featuring anionic2−ribbons separated by Rb+cations. The measured record high photoluminescence quantum yield values range from 64% to 100% for Rb2CuBr3and Rb2CuCl3, respectively. Furthermore, the measured emission linewidths are quite narrow with full width at half maximum values of 54 and 52 nm for Rb2CuBr3and Rb2CuCl3, respectively. Single crystals of Rb2CuCl3demonstrate an anti‐Stokes photoluminescence signal, shown for the first time for Pb‐free metal halides. The discovery of highly efficient narrow blue emitters based on a nontoxic and inexpensive metal copper paves a way for the consideration of low‐cost and environmentally friendly copper halides for practical applications.more » « less
-
All‐inorganic copper(I) halides have recently emerged as attractive alternatives to lead‐based halide perovskites and rare‐earth‐doped inorganics for light emission applications. Most of the newly discovered all‐inorganic Cu(I) halides demonstrate high‐efficiency blue emission albeit with unusually poor tunability of photoluminescence (PL) properties. This work reports the facile preparation of three new copper(I) halides based on the guanidinium cation: (CN3H6)3CuCl4, (CN3H6)7Cu3Br10·3(C3H7NO), and (CN3H6)7Cu3I10·3(C3H7NO). A comprehensive characterization of PL is presented for these novel materials, which have highly tunable, dual blue–yellow emission responsive to both excitation wavelength and vacuum annealing. These have remarkable photoluminescence quantum yield (PLQY) values of up to 34.6% and color‐rendering indices (CRI) up to 97% for tunable, single‐phase white light emission with correlated color temperatures (CCT) ranging from 4851 to 18 921 K, demonstrating the excellent potential of Cu(I) halides for light emission applications.more » « less
-
Abstract There has been a great deal of recent interest in extended compounds containing Ru3+and Ru4+in light of their range of unusual physical properties. Many of these properties are displayed in compounds with the perovskite and related structures. Here we report an array of structurally diverse hybrid ruthenium halide perovskites and related compounds: MA2RuX6(X=Cl or Br), MA2MRuX6(M=Na, K or Ag;X=Cl or Br) and MA3Ru2X9(X=Br) based upon the use of methylammonium (MA=CH3NH3+) on the perovskite A site. The compounds MA2RuX6with Ru4+crystallize in the trigonal space groupand can be described as vacancy‐ordered double‐perovskites. The ordered compounds MA2MRuX6with M+and Ru3+crystallize in a structure related to BaNiO3with alternatingMX6and RuX6face‐shared octahedra forming linear chains in the trigonalspace group. The compound MA3Ru2Br9crystallizes in the orthorhombic Cmcm space group and displays pairs of face‐sharing octahedra forming isolated Ru2Br9moieties with very short Ru–Ru contacts of 2.789 Å. The structural details, including the role of hydrogen bonding and dimensionality, as well as the optical and magnetic properties of these compounds are described. The magnetic behavior of all three classes of compounds is influenced by spin–orbit coupling and their temperature‐dependent behavior has been compared with the predictions of the appropriate Kotani models.more » « less
-
Abstract Non‐porous small molecule adsorbents such as {[3,5‐(CF3)2Pz]Cu}3(where Pz=pyrazolate) are an emerging class of materials that display attractive features for ethene−ethane separation. This work examines the chemistry of fluorinated copper(I) pyrazolates {[3,5‐(CF3)2Pz]Cu}3and {[4‐Br‐3,5‐(CF3)2Pz]Cu}3with much larger 1‐butene in both solution and solid state, and reports the isolation of rare 1‐butene complexes of copper(I), {[3,5‐(CF3)2Pz]Cu(H2C=CHC2H5)}2and {[4‐Br‐3,5‐(CF3)2Pz]Cu(H2C=CHC2H5)}2and their structural, spectroscopic, and computational data. The copper−butene adduct formation in solution involves olefin‐induced structural transformation of trinuclear copper(I) pyrazolates to dinuclear mixed‐ligand systems. Remarkably, larger 1‐butene is able to penetrate the dense solid material and to coordinate with copper(I) ions at high molar occupancy. A comparison to analogous ethene and propene complexes of copper(I) is also provided.more » « less
