Radiation detection, using materials to convert high-energy photons to low-energy photons (X-ray imaging) or electrical charges (X-ray detector), has become essential for a wide range of applicatio

Metal Halide Perovskites for X-ray Imaging Scintillators and Detectors

Halide solid-state electrolytes (SSEs) with high room-temperature ionic conductivity (>10−3 S cm−1), wide electrochemical windows, and good compatibility toward oxide cathode materials have achieved impressive progress and attracted significant attention for application in all-solid-state lithium batteries (ASSLBs). This review presents an overview of halide SSEs, including their development, structure, ionic conductivity, chemical stability, and current limitations. Firstly, we give a brief overview of the historical development of halide-based SSEs, followed by an introduction to the different types of halide SSEs. From a practical point of view, the synthesis methods, especially scalable liquid-phase synthesis, are intensively discussed. Then, the associated stability issues involving basic structure stability, air/humidity stability, and electrochemical stability (electrolyte/SSE interface and electrochemical stability window) are also discussed in detail. Comprehensive coverage and thorough understanding of the properties of halide SSEs are provided and it is expected to help guide the development of future SSEs towards ASSLBs for energy storage applications.

Progress and perspectives on halide lithium conductors for all-solid-state lithium batteries

Heterojunction engineering has played an indispensable role in the exploitation of innovative artificial materials with exceptional properties and has consequently triggered a new revolution in achieving high-performance optoelectronic devices. Herein, an intriguing halide perovskite (PVK) and metal dichalcogenide (MD) heterojunction, i.e., a lead-free Cs2SnI6 perovskite nanocrystal/SnS2 nanosheet hybrid, was fabricated in situ for the first time. Comprehensive investigations with experimental characterizations and theoretical calculations demonstrate that cosharing of the Sn atom enables intimate contact in the Cs2SnI6/SnS2 hybrid together with a type II band alignment structure. Additionally, ultrafast carrier separation between SnS2 and Cs2SnI6 has been observed in the Cs2SnI6/SnS2 hybrid by transient absorption measurements, which efficiently prolongs the lifetime of the photogenerated electrons in SnS2 (from 1290 to 3080 ps). The resultant spatial charge separation in the Cs2SnI6/SnS2 hybrid evidenced by Kelvin probe force microscopy (KPFM) significantly boosts the photocatalytic activity toward CO2 reduction and the photoelectrochemical performance, with 5.4-fold and 10.6-fold enhancements compared with unadorned SnS2. This work provides a facile and effective method for the in situ preparation of PVK-MD heterojunctions, which may significantly stimulate the synthesis of various perovskite-based hybrid materials and their further optoelectronic applications.

In Situ Construction of a Cs2SnI6 Perovskite Nanocrystal/SnS2 Nanosheet Heterojunction with Boosted Interfacial Charge Transfer.

Zero-dimensional (0D) all-inorganic/organic-inorganic metal halides, as emerging luminescent materials, have attracted unparalleled interest from versatile perspectives due to their unique crystallographic/electronic structures with isolated building units and fascinating optical characteristics. However, significant challenges still exist for 0D metal halides, including their chemical molecular design, photoluminescence (PL) mechanism, PL modification and applications. In this review, we summarize the 0D metal halides through the classification of all-inorganic and organic-inorganic hybrid metal halides, and further emphasize the unique role of B-site cations with different electronic configurations in the PL process. Furthermore, the PL mechanisms focusing on the self-trapped excitons (STEs) model and PL regulation engineering are examined to explore their extraordinary PL properties and further reveal new application prospects. This review aims to provide in-depth insight into the structure-luminescence-application relationship of 0D metal halides and pave the way for the realization of next-generation high-performance luminescent materials.

Recent progress of zero-dimensional luminescent metal halides

All-Solid-State Z-Scheme α-Fe2O3/Amine-RGO/CsPbBr3 Hybrids for Visible-Light-Driven Photocatalytic CO2 Reduction

Low-dimensional luminescent lead halide perovskites have attracted tremendous attention for their fascinating optoelectronic properties, while the toxicity of lead is still considered a drawback. Herein, we report a novel lead-free zero-dimensional (0D) indium-based perovskite (Cs2 InBr5 ⋅H2 O) single crystal that is red-luminescent with a high photoluminescence quantum yield (PLQY) of 33 %. Experimental and computational studies reveal that the strong PL emission might originate from self-trapping excitons (STEs) that result from an excited-state structural deformation. More importantly, the in situ transformation between hydrated Cs2 InBr5 ⋅H2 O and the dehydrated form is accompanied with a switchable dual emission, which enables it to act as a PL water-sensor in humidity detection or the detection of traces of water in organic solvents.

A Highly Red-Emissive Lead-Free Indium-Based Perovskite Single Crystal for Sensitive Water Detection.

Low-dimensional lead halide perovskite materials recently have drawn much attention owing to the intriguing broadband emissions; however, the toxicity of lead will hinder their future development. Now, a lead-free (C4 H14 N2 )2 In2 Br10 single crystal with a unique zero-dimensional (0D) structure constituted by [InBr6 ]3- octahedral and [InBr4 ]- tetrahedral units is described. The single crystal exhibits broadband photoluminescence (PL) that spans almost the whole visible spectrum with a lifetime of 3.2 μs. Computational and experimental studies unveil that an excited-state structural distortion in [InBr6 ]3- octahedral units enables the formation of intrinsic self-trapped excitons (STEs) and thus contributing the broad emission. Furthermore, femtosecond transient absorption (fs-TA) measurement reveals that the ultrafast STEs formation together with an efficient intersystem crossing has made a significant contribution to the long-lived and broad STE-based emission behavior.

Intrinsic Self‐Trapped Emission in 0D Lead‐Free (C 4 H 14 N 2 ) 2 In 2 Br 10 Single Crystal

Summary A luminescent all-inorganic manganese-bismuth heterometallic Cs4MnBi2Cl12 perovskite single crystal has been synthesized with a [BiCl6]3−-[MnCl6]4−-[BiCl6]3− triple-layered two-dimensional structure Benefit from the effective energy transfer from [BiCl6]3− octahedron donor to luminescent [MnCl6]4− acceptor, Cs4MnBi2Cl12 shows a photoluminescence quantum yield (PLQY) of up to 257% (~610 nm), 51-fold higher than the Bi unalloyed CsMnCl3·2H2O counterpart Suggested by the theoretical calculations, Bi and Mn exhibit hybridization in conduction and valence band, which further results in a favorable low activation energy for exciton transfer (~23 meV) By virtue of all-inorganic chemical composition, Cs4MnBi2Cl12 exhibits impressive stability toward moisture, light, and heat Furthermore, Cs4MnBi2Cl12 features strong soft X-ray attenuation and bright radiative luminescence under X-ray excitation, which pave a way for its application in medical flat-panel X-ray digital radiography This work presents a new avenue toward fabrication of function-directed material with tailored photoelectric properties

All-Inorganic Lead-Free Heterometallic Cs4MnBi2Cl12 Perovskite Single Crystal with Highly Efficient Orange Emission

Although single-source white emissive perovskite has emerged as a class of encouraging light-emitting material, the synthesis of lead-free halide perovskite materials with high luminous efficiency is still challenging. Here, we report a series of zero-dimensional indium-antimony (In/Sb) alloyed halide single crystals, BAPPIn2–2xSb2xCl10 (BAPP = C10H28N4, x = 0 to 1), with tunable emission. In BAPPIn1.996Sb0.004Cl10, bright yellow emission with near 100% photoluminescence quantum yield (PLQY) is yielded when it was excited at 320 nm, which turns into bright white-light emission with a PLQY of 44.0% when excited at 365 nm. Combined spectroscopy and theoretical studies reveal that the BAPP4+-associated blue emission and inorganic polyhedron–afforded orange emission function as a perfect pair of complementary colors affording white light in BAPPIn1.996Sb0.004Cl10. Moreover, the interesting afterglow behavior, together with excitation-dependent emission property, makes BAPPIn2–2xSb2xCl10 as high-performance anti-counterfeiting/information storage materials.

https://advances.sciencemag.org/content/advances/7/34/eabg3989.full.pdf

Jun-Hua Wei

Papers

A Highly Red-Emissive Lead-Free Indium-Based Perovskite Single Crystal for Sensitive Water Detection.

Intrinsic Self‐Trapped Emission in 0D Lead‐Free (C 4 H 14 N 2 ) 2 In 2 Br 10 Single Crystal

All-Inorganic Lead-Free Heterometallic Cs4MnBi2Cl12 Perovskite Single Crystal with Highly Efficient Orange Emission

Indium-antimony-halide single crystals for high-efficiency white-light emission and anti-counterfeiting

Activation of Self-Trapped Emission in Stable Bismuth-Halide Perovskite by Suppressing Strong Exciton–Phonon Coupling