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Building a reliable relationship between the electronic structure of alloyed metallic catalysts and catalytic performance is important but remains challenging due to the interference from many entangled factors. Herein, a PdBi surface alloy structural model, by tuning the deposition rate of Bi atoms relative to the atomic interdiffusion rate at the interface, realizes a continuous modulation of the electronic structure of Pd. Using advanced X-ray characterization techniques, we provide a precise depiction of the electronic structure of the PdBi surface alloy. As a result, the PdBi catalysts show enhanced propene selectivity compared with the pure Pd catalyst in the selective hydrogenation of propyne. The prevented formation of saturated β-hydrides in the subsurface layers and weakened propene adsorption on the surface contribute to the high selectivity. Our work provides in-depth understanding of the electronic properties of surface alloy structure and underlies the study of the electronic structure-performance relationship in bimetallic catalysts.

While tuning the electronic structure of Pt can thermodynamically alleviate CO poisoning in direct methanol fuel cells, the impact of interactions between intermediates on the reaction pathway is seldom studied. Herein, we contrive a PtBi model catalyst and realize a complete inhibition of the CO pathway and concurrent enhancement of the formate pathway in the alkaline methanol electrooxidation. The key role of Bi is enriching OH adsorbates (OH

Lead halide perovskite nanocrystals (CsPbX3 NCs) have been regarded as promising materials in photocatalysis. Combining metal single atoms with CsPbX3 NCs may be a practical way in exploring perovskite-based catalysts. However, such hybrids have not been achieved experimentally yet, mainly due to the weak interaction between the metal atom and the CsPbX3 surface. Here, we demonstrate that Pt single atoms can be deposited on CsPbBr3 NCs through a photoassisted approach, in which the surface was partially oxidized first, followed by the anchoring of Pt single atoms through the formation of Pt-O and Pt-Br bonds. The deposition of Pt single atoms can significantly change the photophysical properties of CsPbBr3 NCs by inducing the generation of deep trap states in the band gap. The as-prepared Pt-SA/CsPbBr3 can be used as efficient and durable catalysts for photocatalytic semi-hydrogenation of propyne. A CsPbBr3 nanocrystal might be a suitable substrate for anchoring other metal single atoms, such as Cu, Au, Ag, Pd, and so on.

Controllable fabrication of Fe-N-C based single-atom catalysts (SACs) for enhanced electrocatalytic performance is highly desirable but still challenging. Here, an in situ surface-confined strategy was demonstrated for the synthesis of single atomic Fe-N4 on N-doped carbon nanoleaves (L-FeNC). The in situ generated Zn3[Fe(CN)6]2 could not only serve as a protection layer against collapse of nanoleaves but also provide abundant Fe source for the formation of Fe-N moieties during pyrolysis, leading to high surface area and high graphitization degree of L-FeNC simultaneously. Benefiting from abundant Fe-N4 active sites, enhanced mass and charge transfer, the as-prepared L-FeNC manifested a half-wave potential of 0.89 V for oxygen reduction reaction (ORR) in 0.1 M KOH. A maximum power density of 140 mW cm−2 and stable discharge voltage even after operation for 50,000 s have been demonstrated when the L-FeNC was used as air cathode for Zn-air battery. This work not only provided a unique surface-confined strategy for the synthesis of two-dimensional nanocarbons, but also demonstrated the significant benefit from rational design and engineering of Fe-N-C SACs, thus offering great opportunities for fabrication of efficient energy conversion and storage devices.

The reverse water–gas shift (RWGS) reaction is a critical step for adjusting the CO/H2 ratio in crude syngas via CO2 hydrogenation in the chemical industry. Generally, the conditioning of syngas co...

One of the main challenges of all-inorganic cesium lead halide (CsPbX3) perovskite nanocrystals (NCs) in photocatalysis is their poor stability in hostile environments such as polar solvents. Herei...

The slow kinetics at the cathode of oxygen reduction reaction (ORR) seriously limits the efficiencies of fuel cells and metal-air batteries. Pt, the state-of-the-art ORR electrocatalyst, suffers from high cost, low earth abundance, and poor stability. Here a self-templated strategy based on metal-organic frameworks (MOFs) is proposed for the fabrication of hollow nitrogen-doped carbon spheres that are embedded with cobalt nanoparticles (Co/HNC). The Co/HNC manifests better ORR activities, methanol tolerance, and stability than commercial Pt/C. The high ORR performance of Co/NHC can be attributed to the hollow structure which provides enlarged electrochemically active surface area, the formation of more Co-N species, and the introduction of defects. This work highlights the significance of rational engineering of MOFs for enhanced ORR activity and stability and offers new routes to the design and synthesis of high-performance electrocatalysts.

All-inorganic lead halide perovskite nanocrystals (NCs) have been promising candidates in various optoelectrical fields. It is still challenging to further enhance their optical properties and stability to meet the requirements of practical applications. Herein, we develop a passivation strategy towards CsPbBr3 NCs by using inorganic phosphate and bromide anions. Phosphate can coordinate with lead ions on CsPbBr3 NCs as capping ligands; meanwhile, excess bromide can strengthen the repair of surface trapping sites. The treated NCs exhibit near-unity quantum yield and boosted radiative recombination. In addition, obvious enhancement has been realized in their durability against polar solvents. A white light emitting diode (WLED) has been fabricated by employing the passivated NCs as a green light source, which possesses high luminous efficiency and operational stability.

Lead halide perovskite NCs (APbX3, A = formamidinium (FA), methylammonium (MA) or Cs; X = Cl, Br, I or their mixture) have attracted unprecedented attention due to their excellent photophysical properties and wide application prospects. However, the inherent ionic structure of APbX3 NCs makes them very sensitive to external conditions such as water and oxygen, resulting in poor stability. As a feasible strategy, encapsulation is considered to be effective in improving the stability. In this minireview, we focus on single-particle-level coating, which not only can improve the stability but also maintain the nano effect of the original NCs. This review summarizes the fundamental information on APbX3 NCs and the necessity of single-particle-level coating. Subsequently, a variety of heterostructures at the single-particle level are introduced in detail. Then, their applications are summarized. Moreover, we discuss the challenges and prospects of the single-particle-level heterostructures based on APbX3 NCs.

In this work, we report a simple one-pot reprecipitation method of CsPbX3/Pb3(PO4)2 composite nanocrystals (NCs), which have significantly improved photophysical properties and stability. The as-obtained CsPbBr3/Pb3(PO4)2 NCs display bright green emission with a high PLQY of 95%. In addition, the product has an outstanding stability toward moisture and polar solvents, superior to that of pristine CsPbBr3 NCs. This work not only provides a facile method for preparing lead halide perovskite NCs with high quality, but also sheds some light on the potential of inorganic salts as passivators.

Although lead halide perovskites are demonstrated to be promising photocatalysts for hydrogen evolution from hydrogen halide splitting, it still remains challenging to fabricate efficient and stabl...

Hydrochromic materials that can reversibly change color upon water treatment have attracted much attention owing to their potential applications in diverse fields. Herein, for the first time, we report that space-confined CsPbBr3 nanocrystals (NCs) are hydrochromic. When CsPbBr3 NCs are loaded into a porous matrix, reversible transition between luminescent CsPbBr3 and non-luminescent CsPb2 Br5 can be achieved upon the exposure/removal of water. The potential applications of hydrochromic CsPbBr3 NCs in anti-counterfeiting are demonstrated by using CsPbBr3 NCs@mesoporous silica nanospheres (around 100 nm) as the starting material. Owing to the small particle size and negatively charged surface, the as-prepared particles can be laser-jet printed with high precision and high speed. We demonstrate the excellent stability over repeated transformation cycles without color fade. This new discovery may not only deepen the understanding of CsPbX3 , but also open a new way to design CsPbX3 materials for new applications.

All-inorganic lead halide perovskite (CsPbX

Creating highly branched plasmonic superparticles can effectively induce broadband light absorption and convert light to heat regardless of the light wavelength, angle, and polarization. However, their direct synthesis in a controllable manner remains a significant challenge. In this work, we propose a strain modulation strategy to produce branched Au nanostructures that promotes the growth of Au on Au seeds in the Volmer-Weber (island) mode instead of the typical Frank-van der Merwe (layer-by-layer) mode. The key to this strategy is to continuously deposit polydopamine formed in situ on the growing surface of the seeds to increase the chemical potential of the subsequent deposition of Au, thus achieving continuous heterogeneous nucleation and growth. The branched Au superparticles exhibit a photothermal conversion efficiency of 91.0% thanks to their small scattering cross-section and direction-independent absorption. Even at a low light power of 0.5 W/cm2 and a low dosage of 25 ppm, these particles show an excellent efficacy in photothermal cancer therapy. This work provides the fundamental basis for designing branched plasmonic nanostructures and expands the application scope of the plasmonic photothermal effect.

This work reports a CsI stripping/insertion process that enables the reversible transformation between blue-emissive Cs3Cu2I5 and yellow-emissive CsCu2I3 upon moisture/evaporation treatment. The successful transformation can be ascribed to the unique space confinement of the SiO2 matrix and ligand-free feature of perovskite nanocrystals, which can be a good candidate for anti-counterfeiting.

X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX3 nanocrystals (NCs). However, the proton exchange between coordinated OAm and O...

To improve the efficiency of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) based light-emitting diodes (LEDs), several parameters should be taken into consideration, including outstanding photophysical properties, efficient charge injection/transporting properties, and suitable device structure. In traditional synthesis of CsPbX3 nanocrystals, oleic acid and oleylamine are widely used as ligands, which require a complicated cleaning step to remove extra residual insulating ligands. In this work, monodisperse CsPbBr3 nanorods with tunable aspect ratio and a clean surface have been prepared through an interfacial conversion from Cs4PbBr6 nanocrystals. The formation process has been carefully investigated. The nanorods showed excellent photophysical properties, including a photoluminescence quantum yield up to 87% and a photoluminescence lifetime of 44 ns. According to the ultraviolet photoelectron spectroscopy measurement, CsPbBr3 nanorods show a higher valence band maximum than that of nanocubes, suggesting a ...

We presented here a solvothermal approach to synthesize CsPbX3 nanostructures with precisely controlled dimensions. By simply varying the amount of Cs precursor, three-dimensional nanocubes, two-dimensional nanoplatelets/nanoribbons and one-dimensional nanorods with high uniformity in morphology and size were successfully synthesized. A stoichiometry defined growth mechanism has been proposed to explain the growth mechanism. This work not only adds another effective tool in the synthesis toolbox, but also helps to understand the formation mechanism of CsPbX3 nanostructures.

The oxygen reduction reaction (ORR) plays a key role in many renewable energy conversion and storage technologies. As the state-of-the-art ORR electrocatalysts, Pt-based electrocatalysts suffer from high price, low earth abundance and poor stability. Developing high performance noble-metal-free ORR electrocatalysts as alternatives for Pt is highly desirable but still remains a significant challenge. In this work, we reported a metal–organic-framework-engaged strategy for the fabrication of cobalt-tipped carbon nanotube/Ti3C2 nanosheet composites (Co-CNT/Ti3C2), in which ZIF-67 particles were in situ grown on Ti3C2 nanosheets and then were converted to cobalt-tipped carbon nanotubes through a pyrolysis process. The Ti3C2 nanosheets not only served as two-dimensional conductive scaffolds for the growth of Co-CNTs but also balanced the tradeoff between graphitization of carbon and the surface area. Benefiting from the abundant Co–N/C active sites, reasonably high graphitization of carbon and suitable surface areas, the optimized Co-CNT/Ti3C2 manifested comparable ORR activity (half-wave potential of 0.82 V and diffusion-limiting current density of 5.55 mA cm−2) but superior stability to commercial Pt/C (half-wave potential of 0.82 V and diffusion-limiting current density of 5.30 mA cm−2), providing great opportunity for its application in renewable conversion and storage technologies.

Recently, all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, I) perovskite nanocrystals (NCs) have attracted much attention because of their excellent photophysical properties and promising applications in diverse fields. In this review article, the synthetic methods have been briefly summarized first, followed by the morphological control of CsPbX3 NCs. To improve their photophysical properties as well as stability, surface passivation strategies, such as chemical treatment and encapsulation approaches, are used and have been summarized. Their representative applications in various fields, including light emitting diodes (LEDs), solar cells, photodetectors, lasers and photocatalysis, have been introduced. Finally, a brief outlook of this field has been proposed to point out some important challenges and possible solutions.

With the growing demand for the next-generation light emitting diode (LED) display and lighting, considerable progress has been realized in the development of various LEDs for research and consumer market. Among diverse emitting materials, all-inorganic perovskite CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) have emerged as active and promising candidates in LEDs due to their high photoluminescence quantum yield (PLQY), high color purity and tunable emission. Over the past four years, a deeper understanding and higher efficiency have been achieved in CsPbX3 NC-based LEDs. These encouraging facts foreshadow the further progress and commercialization in this burgeoning field. Herein, the recent advancements in CsPbX3 NC-based LEDs have been reviewed. The synthesis and passivation methods of CsPbX3 NCs are firstly introduced. Then we summarize the approaches for the fabrication of highly efficient and stable LEDs based on CsPbX3 NCs, including the modification of emitting layers and optimization of structures. Finally, some challenges and possible solutions are suggested for the development of CsPbX3 NC-based LEDs.

Smart fluorescent materials have attracted much attention due to their promising applications in various fields. Here, we demonstrate a reversible fluorescence switching of CsPbI3 nanocrystals (NCs) using photochromic AgI NCs as the photosensitizer. Upon light irradiation, AgI NCs are decomposed into metallic Ag and elemental I2, leading to the formation of Ag–CsPbI3 heterostructures. Because Ag has a lower Fermi level than that of CsPbI3, excited electrons will transfer from CsPbI3 to Ag, resulting in the quenching of photoluminescence emission. When the composite is stored in the dark, metallic Ag is oxidized into AgI, and the PL emission of CsPbI3 NCs can be recovered. The application of the AgI/CsPbI3 system has been demonstrated as a rewritable platform. This work may shed light on the exploration of CsPbX3 NCs for applications in smart fluorescent materials.

All-inorganic lead halide perovskite nanocrystals (NCs) have been promising candidates in various optoelectrical fields. It is still challenging to further enhance their optical properties and stability to meet the requirements of practical applications. Herein, we develop a passivation strategy towards CsPbBr3 NCs by using inorganic phosphate and bromide anions. Phosphate can coordinate with lead ions on CsPbBr3 NCs as capping ligands; meanwhile, excess bromide can strengthen the repair of surface trapping sites. The treated NCs exhibit near-unity quantum yield and boosted radiative recombination. In addition, obvious enhancement has been realized in their durability against polar solvents. A white light emitting diode (WLED) has been fabricated by employing the passivated NCs as a green light source, which possesses high luminous efficiency and operational stability.

Butadiene (BD) is a critical raw material in chemical industry, which is conventionally produced from naphtha cracking. The fast-growing demand of BD and the limited oil reserve motivate chemists to develop alternative methods for BD production. Shale gas, which mainly consists of light alkanes, has been considered as cheap raw materials to replace oil for BD production via n-butane direct dehydrogenation (n-BDH). However, the quest for highly-efficient catalysts for n-BDH is driven by the current drawback of low BD selectivity. Here, we demonstrate a strategy for boosting the selectivity of BD by suppressing dehydroisomerization, an inevitable step in the conventional n-BDH process which largely reduces the selectivity of BD. Detailed investigations show that the addition of alkali-earth metals (e. g., Mg and Ca) into Pt-Ga2 O3 /S10 catalysts increases Pt dispersity, suppresses coke deposition and dehydroisomerization, and thus leads to the significant increase of BD selectivity. The optimized catalyst displays an initial BD selectivity of 34.7 % at a n-butane conversion of 82.1 % at 625 °C, which outperforms the reported catalysts in literatures. This work not only provides efficient catalysts for BD production via n-BDH, but also promotes the researches on catalyst design in heterogeneous catalysis.

One of the main challenges of all-inorganic cesium lead halide (CsPbX

Although lead halide perovskites are demonstrated to be promising photocatalysts for hydrogen evolution from hydrogen halide splitting, it still remains challenging to fabricate efficient and stable catalysts. Here MoS

Developing efficient Pt-based electrocatalysts for the methanol oxidation reaction (MOR) is of pivotal importance for large-scale application of direct methanol fuel cells (DMFCs), but Pt suffers from severe deactivation brought by the carbonaceous intermediates such as CO. Here, we demonstrate the formation of a bismuth oxyhydroxide (BiOx(OH)y)-Pt inverse interface via electrochemical reconstruction for enhanced methanol oxidation. By combining density functional theory calculations, X-ray absorption spectroscopy, ambient pressure X-ray photoelectron spectroscopy, and electrochemical characterizations, we reveal that the BiOx(OH)y-Pt inverse interface can induce the electron deficiency of neighboring Pt; this would result in weakened CO adsorption and strengthened OH adsorption, thereby facilitating the removal of the poisonous intermediates and ensuring the high activity and good stability of Pt2Bi sample. This work provides a comprehensive understanding of the inverse interface structure and deep insight into the active sites for MOR, offering great opportunities for rational fabrication of efficient electrocatalysts for DMFCs.

Hydrochromic materials that can reversibly change color upon water treatment have attracted much attention owing to their potential applications in diverse fields. Herein, for the first time, we report that space-confined CsPbBr

All-inorganic metal halide perovskite (e.g., CsPbX3, X = Cl, Br, I) nanocrystals show excellent shape-dependent photophysical properties which have motivated the active exploration of new synthetic approaches for higher morphological complexity than those produced by current methods (cubes, plates, rods). Here, for the first time, we demonstrate that the transformation of Cs4PbBr6 to CsPbBr3 coupled with an overgrowth scheme can be exploited to produce CsPbBr3 dodecapods, each of which is composed of 12 well-defined branches. The critical step is the formation of cuboctahedral Cs4PbBr6 seeds in a Cs-rich environment induced by the faster dissolution of CsOAc than PbBr2. A phase transformation from Cs4PbBr6 to CsPbBr3 then leads to the growth of twelve branches from the twelve vertices, producing CsPbBr3 dodecapods with a high photoluminescence quantum yield (50%) and a narrow full width at half maximum (18 nm). We further demonstrate the production of dodecapods of CsPbX3 (X = Cl, I) NCs with tunable emission covering the full visible region (415–685 nm) through an anion exchange process. Furthermore, white light emitting diodes (WLEDs) fabricated with CsPbBr3 nanoflowers demonstrated a 135% color gamut of the National Television System Committee (NTSC) standard. This work not only adds a distinct new morphology to the CsPbX3 nanocrystal family but also sheds light on the fundamental understanding of the growth mechanism of these newly emerged functional materials.

As a promising material, Cs4PbX6 (X = Cl, Br, I) nanocrystals (NCs) have attracted much attention. However, their luminescent property is still under debate. In this work, we first systematically studied the colloidal preparation of Cs4PbX6 NCs. It is found that the critical parameter for the formation of Cs4PbX6 NCs is the ratio between Cs and Pb. Pure Cs4PbX6 NCs are nonluminescent. The luminescence property of previous reported Cs4PbX6 NCs may come from the impurity of luminescent CsPbX3 NCs. No coexistence of both Cs4PbX6 and CsPbX3 phase has been found in one single nanoparticle. The water-triggered transformation from nonluminescent Cs4PbX6 NCs to luminescent CsPbX3 NCs has been quantitatively studied. The potential application of Cs4PbX6 NCs in humidity sensor and anticounterfeiting have been demonstrated. This work is important because it not only confirmed the nonluminescent nature of Cs4PbX6 NCs but also demonstrated the potential application of such NCs.

The practical applications of CsPbX3 nanocrystals (NCs) have been limited by their poor stability. Although much effort has been devoted to making core–shell nanostructures to enhance the stability of CsPbX3 NCs, it is still very difficult to coat CsPbX3 NCs with another material on a single-particle level. In this work, we report a facile one-pot approach to synthesize CsPbBr3@SiO2 core–shell nanoparticles (NPs), in which each core–shell NP has only one CsPbBr3 NC. The formation process has been carefully monitored. It has been found that the formation rates, determined by reaction temperature, precursor species, pH value, etc., of both CsPbBr3 and SiO2 are critical for the successful preparation of core–shell NPs. Thanks to the protection of SiO2 shell, the product shows much higher long-term stability in humid air and enhanced stability against ultrasonication treatment in water than that of naked CsPbBr3 NCs. This work not only provides a robust method for the preparation of core–shell nanostructures ...

Depositing noble metals on specific facets of semiconductors can improve the separation of photoexcited hole-electron pairs during the photocatalytic reaction, resulting in enhanced photocatalytic performance. This work describes the selective deposition of noble metal nanoparticles (Au, Pt, Pd) on some specific facets of p-type Co3 O4 through a simple and facile photoassisted method. The deposition of Au nanoparticles (NPs) on {111} facets of Co3 O4 nanocrystals (NCs) can remarkably improve their photocatalytic activity towards water oxidation, which can be attributed to enhanced charge spatial separation. Moreover, the magnetically separated photocatalysts are good examples of new designed photocatalysts that can be recovered easily.

The poor stability of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) has severely impeded their practical applications. Although there are some successful examples on encapsulating multiple CsPbX3 NCs into an oxide or polymer matrix, it has remained a serious challenge for the surface modification/encapsulation using oxides or polymers at a single particle level. In this work, monodisperse CsPbX3/SiO2 and CsPbBr3/Ta2O5 Janus nanoparticles were successfully prepared by combining a water-triggered transformation process and a sol–gel method. The CsPbBr3/SiO2 NCs exhibited a photoluminescence quantum yield of 80% and a lifetime of 19.8 ns. The product showed dramatically improved stability against destruction by air, water, and light irradiation. Upon continuous irradiation by intense UV light for 10 h, a film of the CsPbBr3/SiO2 Janus NCs showed only a slight drop (2%) in the PL intensity, while a control sample of unmodified CsPbBr3 NCs displayed a 35% drop. We further highlighted the advantageous features of t...

Recently, all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have drawn wide attention because of their excellent optoelectronic properties and potential applications. However, one of the most significant challenges of such NCs is their low stability against protonic solvents. In this work, we demonstrate that by incorporating a highly branched capping ligand, trioctylphosphine oxide (TOPO), into the traditional oleic acid/oleylamine system, monodisperse CsPbX3 NCs with excellent optoelectronic properties can be achieved at elevated temperatures (up to 260 °C). The size of such NCs can be varied in a relatively wide range. The capping of TOPO on NCs has been verified through Fourier transform infrared spectroscopy measurement. More importantly, the presence of TOPO can dramatically improve the stability of CsPbX3 NCs against ethanol treatment. After ethanol treatment for 100 min, the emission intensity of the TOPO-capped sample dropped only 5%, whereas that of non-TOPO-capped ...

We report a novel CsX-stripping mechanism that enables the efficient chemical transformation of nonluminescent Cs4PbX6 (X = Cl, Br, I) nanocrystals (NCs) to highly luminescent CsPbX3 NCs. During the transformation, Cs4PbX6 NCs dispersed in a nonpolar solvent are converted into CsPbX3 NCs by stripping CsX through an interfacial reaction with water in a different phase. This process takes advantage of the high solubility of CsX in water as well as the ionic nature and high ion diffusion property of Cs4PbX6 NCs, and produces monodisperse and air-stable CsPbX3 NCs with controllable halide composition, tunable emission wavelength covering the full visible range, narrow emission width, and high photoluminescent quantum yield (up to 75%). An additional advantage is that this is a clean synthesis as Cs4PbX6 NCs are converted into CsPbX3 NCs in the nonpolar phase while the byproduct of CsX is formed in water that could be easily separated from the organic phase. The as-prepared CsPbX3 NCs show enhanced stability a...

X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX

Smart fluorescent materials have attracted much attention due to their promising applications in various fields. Here, we demonstrate a reversible fluorescence switching of CsPbI3 nanocrystals (NCs) using photochromic AgI NCs as the photosensitizer. Upon light irradiation, AgI NCs are decomposed into metallic Ag and elemental I2, leading to the formation of Ag-CsPbI3 heterostructures. Because Ag has a lower Fermi level than that of CsPbI3, excited electrons will transfer from CsPbI3 to Ag, resulting in the quenching of photoluminescence emission. When the composite is stored in the dark, metallic Ag is oxidized into AgI, and the PL emission of CsPbI3 NCs can be recovered. The application of the AgI/CsPbI3 system has been demonstrated as a rewritable platform. This work may shed light on the exploration of CsPbX3 NCs for applications in smart fluorescent materials.

Although all-inorganic CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) have been considered as a promising material for photoelectronic devices, their applications are still limited because of their poor stability and the lack of in-depth understanding. Here, we demonstrate a post-treatment method for the preparation of ultrathin CsPbX3 nanowires (NWs) by treating CsPbBr3 nanocubes with thiourea solution. A systematic study showed a consecutive interfacial transformation process, in which CsPbBr3 nanocubes were first converted to Cs4PbBr6 NCs in the presence of thiourea, followed by a further transformation to CsPbBr3 NCs through an interfacial CsX-stripping process. To reduce the surface energy, an oriented attachment process has been realized and CsPbBr3 NCs aggregated to form ultrathin NWs. The ultrathin CsPbBr3 NWs exhibited high photoluminescence quantum yield (up to 60%) and high resistance to water treatment, which can be attributed to the surface passivation by thiourea. In addition to thiourea, cystein...