Buffering Donor Shuttles in Proton-Coupled Electron Transfer Kinetics for Electrochemical Hydrogenation of Hydroxyacetone to Propylene Glycol.

Electrochemical hydrogenation reactions demand rapid proton-coupled electron transfer at the electrode surface, the kinetics of which depend closely on pH. Buffer electrolytes are extensively employed to regulate pH over a wide range. However, the specific role of buffer species should be taken into account when interpreting the intrinsic pH dependence, which is easily overlooked in the current research. Herein, we report the electrochemical hydrogenation of hydroxyacetone, derived from glycerol feedstock, to propylene glycol with a faradaic efficiency of 56 ± 5% on a polycrystalline Cu electrode. The reaction activities are comparable in citrate, phosphate, and borate buffer electrolytes, encompassing different buffer identities and pH. The electrokinetic profile reveals that citrate is a site-blocking adsorbate on the Cu surface, thereby decreasing buffer concentration and increasing pH will enhance the reaction rate; phosphate is an explicit proton donor, which promotes the interfacial rate by increasing buffer concentration and decreasing pH, while borate is an innocent buffer, which can be used to investigate the intrinsic pH effect. Combined with in situ SEIRAS, we demonstrate that water is the primary proton source in citrate and borate electrolytes, reiterating the rationality of the proposed mechanism based on the microkinetic modeling. Our results emphasize the intrinsic complexity of the buffer system on the kinetic activity for electrocatalysis. It calls for special care when we diagnose the mechanistic pathway in buffer electrolytes convoluted by different buffer identities and pH.

Abdominal Symptom Improvement During Clinical Trials of Tenapanor in Patients With Irritable Bowel Syndrome With Constipation: A Post Hoc Analysis.

INTRODUCTION: This post hoc analysis evaluated the efficacy of tenapanor on abdominal symptoms in patients with irritable bowel syndrome with constipation. Abdominal symptoms assessed included pain, discomfort, bloating, cramping, and fullness. METHODS: The abdominal symptom data were pooled from 3 randomized controlled trials (NCT01923428, T3MPO-1 [NCT02621892], and T3MPO-2 [NCT02686138]). Weekly scores were calculated for each abdominal symptom, and the Abdominal Score (AS) was derived as the average of weekly scores for abdominal pain, discomfort, and bloating. The overall change from baseline during the 12 weeks was assessed for each symptom weekly score and the AS. The AS 6/12-week and 9/12-week response rates (AS improvement of ≥2 points for ≥6/12- or ≥9/12-week) were also evaluated. The association of weekly AS response status (reduction of ≥30%) with weekly complete spontaneous bowel movement (CSBM) status (=0 and >0) was assessed. RESULTS: Among 1,372 patients (684 tenapanor [50 mg twice a day] and 688 placebo), the least squares mean change from baseline in AS was -2.66 for tenapanor vs -2.09 for placebo ( P < 0.0001). The 6/12-week AS response rate was 44.4% for tenapanor vs 32.4% for placebo ( P < 0.0001), and for 9/12-week AS, 30.6% for tenapanor vs 20.5% for placebo ( P < 0.0001). A significant association between weekly CSBM status and weekly AS response status was observed each week ( P < 0.0001), with a greater proportion achieving an AS reduction in patients with >0 CSBMs in a week. DISCUSSION: Tenapanor significantly reduced abdominal symptoms in patients with irritable bowel syndrome with constipation, particularly pain, discomfort, and bloating measured by AS, compared with placebo.

Organic ammonium salt assisted crystallization and defect passivation of a quasi-two-dimensional pure blue perovskite at the buried interface.

Quasi-two-dimensional (quasi-2D) perovskites exhibit excellent performance in light-emitting diodes (LEDs). However, the quality of perovskite films prepared via the solution method is significantly impacted by the enormous number of defects that unavoidably form at the grain boundaries and interfaces during the precursor to the crystal formation process. Here, we propose a strategy to assist perovskite crystallization and defect passivation at the buried interface through interfacial modification. The organic ammonium salt, ethylamine chloride (EACl), is added to the hole transport material and modifies the buried interface of the perovskite film. EACl introduces the nucleation sites for perovskite precursors, and promotes the crystallization process of the perovskite grains, contributing to the formation of high-quality perovskite films. At the same time, the presence of Lewis base (-NH2) groups in EACl and their lone electron pairs effectively inactivate unlocated Pb2+ ions at the buried interface, thereby reducing non-radiative recombination. In addition, chloride ions help to mitigate defects and to improve the morphology of perovskite films. Devices with this modification show a higher performance than control devices on all metrics. This work proposes a facile but efficient way for improving quasi-2D pure blue perovskite crystallization and growth.

Electrokinetic Analyses Uncover the Rate-Determining Step of Biomass-Derived Monosaccharide Electroreduction on Copper.

Electrochemical biomass conversion holds promise to upcycle carbon sources and produce valuable products while reducing greenhouse gas emissions. To this end, deep insight into the interfacial mechanism is essential for the rational design of an efficient electrocatalytic route, which is still an area of active research and development. Herein, we report the reduction of dihydroxyacetone (DHA)-the simplest monosaccharide derived from glycerol feedstock-to acetol, the vital chemical intermediate in industries, with faradaic efficiency of 85±5 % on a polycrystalline Cu electrode. DHA reduction follows preceding dehydration by coordination with the carbonyl and hydroxyl groups and the subsequent hydrogenation. The electrokinetic profile indicates that the rate-determining step (RDS) includes a proton-coupled electron transfer (PCET) to the dehydrated intermediate, revealed by coverage-dependent Tafel slope and isotopic labeling experiments. An approximate zero-order dependence of H+ suggests that water acts as the proton donor for the interfacial PCET process. Leveraging these insights, we formulate microkinetic models to illustrate its origin that Eley-Rideal (E-R) dominates over Langmuir-Hinshelwood (L-H) in governing Cu-mediated DHA reduction, offering rational guidance that increasing the concentration of the adsorbed reactant alone would be sufficient to promote the activity in designing practical catalysts.

Device performance improvements in all-inorganic perovskite light-emitting diodes: the role of binary ammonium cation terminals.

All-inorganic perovskites, like CsPbBr3, have gained particular concern due to their excellent material stability. However, aside from the general defect issue in perovskite materials, all-inorganic perovskites also suffer from poor film quality, leading to low device efficiency, especially of perovskite light-emitting diodes (PeLEDs) employing a thin perovskite film as the emission layer. Herein, 1,4-phenyldimethylammonium dibromide (phDMADBr), which has ammonium cations (NH3+) on both terminals, is introduced as the additive in the precursor solution. It is proved that phDMADBr can improve the film coverage; meanwhile, it also presents a more intense passivation effect on point defects than a similar additive with a single NH3+ terminal. As demonstrated by density functional theory (DFT) calculations, phDMADBr tends to anchor onto the Br-dangling bond with both NH3+ tails and enhances the adhesion to the perovskite grain surface. The exposed hydrophobic aryl also protects the perovskite from detrimental environmental factors. Correspondingly, the maximum luminance (Lmax), current efficiency (CE), and device stability of the PeLEDs are enhanced. This work offers special guidance for screening passivation additives for inorganic perovskites.

Longitudinal follow-up and performance validation of an mRNA-based urine test (Xpert® Bladder Cancer Monitor ) for surveillance in patients with non-muscle-invasive bladder cancer.

OBJECTIVE: To evaluate the performance of the Xpert Bladder Cancer Monitor (Xpert; Cepheid, Sunnyvale, CA, USA) test as a predictor of tumour recurrence in patients with non-muscle-invasive bladder cancer (NMIBC). PATIENTS AND METHODS: Patients (n = 429) undergoing surveillance for NMIBC underwent Xpert, cytology, and UroVysion testing. Patients with a positive Xpert and a negative cystoscopy result (positive-negative [PN] group, n = 66) and a control group of double negative patients (negative Xpert and cystoscopy results [NN] group) were followed for 12 months (±90 days). RESULTS: Histology-confirmed recurrences were detected in 58 patients (13.5%). Xpert had an overall sensitivity of 60.3% and a specificity of 76.5%. The sensitivity for high-grade (HG) cancer was 87% with a negative predictive value (NPV) of 99%. Urine cytology showed an overall sensitivity of 23.2% (47.6% sensitivity for HG tumours) and a specificity of 88.3%. In the PN group, 32% (n = 21) developed a recurrence within 12 months, 11 of which were HG tumours. In the NN control group, 14% (n = 9) developed a recurrence and only two were HG tumours. The hazard ratio for developing recurrence in the PN group was 2.68 for all tumours and 6.84 for HG cancer. CONCLUSIONS: The Xpert test has a high sensitivity for detecting the recurrence of cancer and a high NPV for excluding HG cancer. In addition, the data suggest that patients with a positive Xpert assay in the setting of negative cystoscopy are at high risk for recurrence and need close surveillance.

Performance improvements in all-solution processed inverted QLEDs realized by inserting an electron blocking layer.

Highly efficient, all-solution processed inverted quantum dot light-emitting diodes (QLEDs) are demonstrated by employing 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB) layer as electron blocking layer. Electron injection from ZnO electron transport layer to quantum dots (QDs) emission layer (EML) can be adjusted by thickness of TmPyPB layer, enabling the balanced charge carriers in QDs EML. With optimal thickness of this TmPyPB adjuster, 59.7% increment in the device current efficiency (from 8.2 to 13.1 cd A-1) and 46.2% improvement in the maximum luminance (from 31916 to 46674 cd m-2) are achieved, compared with those of the control QLED which has double hole transport layer structure. On the other hand, we find luminescence quenching process, which often happens at the interface of ZnO nanoparticles and QDs, is not obvious in our QLEDs, in which the ZnO layer is fabricated in precursor method, and this conclusion is verified through Time Resolution Photoluminescence test. In a word, this strategy provides a direction for optimizing charge carrier balance in all-solution processed inverted QLED.

Synergistic function of doping and ligand engineering to enhance the photostability and electroluminescence performance of CsPbBr3quantum dots.

The photostability issue of CsPbX3(X = Cl, Br, I) quantum dots (QDs) is one of the key origins for the degradation of their luminescence performance, which hinders their application in lighting and displays. Herein, we report a new method combining doping and ligand engineering, which effectively improves the photostability of CsPbBr3QDs and the performance of QD light-emitting diodes (QLEDs). In this method, ZnBr2is doped into CsPbBr3QDs to reduce surface anion defects; didodecyldimethyl ammonium bromide (DDAB) and tetraoctylammonium bromide (TOAB) hybrid ligands, which have strong adsorption with QDs, are employed to protect the surface and enhance the conductivity of QD layer in QLEDs. The photoluminescence (PL) and transmission electron microscopy measurements prove the effectively improved photostability of CsPbX3QDs. Moreover, reduced defects and improved conductivity by doping and hybrid ligands treatment also enable the improved electroluminescence performance of CsPbX3QDs. The maximum luminance and external quantum efficiency of the QLED with optimized CsPbX3QDs are 3518.9 cd m-2and 5.07%, which are 3.6 and 2.1 times than that of the control device, respectively. Combining doping and hybrid ligands makes perovskite QDs have an extremely promising prospect in future applications of high-definition displays, high-quality lighting, as well as solar cells.

A New Benchmark of Charges Storage in Single-Layer Organic Light-Emitting Diodes Based on Electrical and Optical Characteristics.

The storage of charges in organic light-emitting diodes (OLEDs) has drawn much attention for its damage to device performance as well as the loss to carriers. Thus, it is essential to address the issue and do further investigation. The traditional approach to storage analysis is mainly based on transient measurement since it is sensitive to transient instead of steady signal. In this paper, we proposed a new benchmark to investigate the single-layer OLEDs capable of stored charges with poly (methyl methacrylate) (PMMA), which is just based on electrical and optical characteristics. Since the stored charges contribute both to luminance and current of the devices with PMMA, the area between them can be taken as a benchmark and evaluated the storage of charges. In our experiment, the areas of 4 nm, 6 nm, 8 nm, and 10 nm PMMA devices are 0.348, 0.554, 0.808, and 0.894, respectively, indicating a higher capability of storage in thicker PMMA. It is exactly in line with the results taken from transient electroluminescence (EL) measurement. Thus, this new benchmark is practical and provides a more accessible approach to investigate the storage of charges in OLEDs.

Improving the Quality and Luminescence Performance of All-Inorganic Perovskite Nanomaterials for Light-Emitting Devices by Surface Engineering.

Lead halide perovskites and their applications in the optoelectronic field have garnered intensive interest over the years. Inorganic perovskites (IHP), though a novel class of material, are considered as one of the most promising optoelectronic materials. These materials are widely used in detectors, solar cells, and other devices, owing to their excellent charge-transport properties, high defect tolerance, composition- and size-dependent luminescence, narrow emission, and high photoluminescence quantum yield. In recent years, numerous encouraging achievements have been realized, especially in the research of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) and surface engineering. Therefore, it is necessary to summarize the principles and effects of these surface engineering optimization methods. It is also important to scientifically guide the applications and promote the development of perovskites more efficiently. Herein, the principles of surface ligands are reviewed, and various surface treatment methods used in CsPbX3 NCs as well as quantum-dot light-emitting diodes are presented. Finally, a brief outlook on CsPbX3 NC surface engineering is offered, illustrating the present challenges and the direction in which future investigations are intended to obtain high-quality CsPbX3 NCs that can be utilized in more applications.

Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes.

In this paper, capacitance/conductance-voltage characteristics (C/G-V) under illumination was achieved to investigate the dynamic mechanism of stored charges in OLEDs with a structure of ITO/ PEDOT:PSS/PMMA/Alq3/Al. For all devices, at least two peaks presented in the optical capacitance-voltage curve. Compared to curves of devices under dark, the first peak increased remarkably with a deviation to Vbi, which can be explained in the form of stored charges combined with the optical conductance characteristics. It was also found that a great decrease in capacitance is followed by the collapse of the first peak with PMMA thickness increased. It can account for the presence of interfacial charges, which is proved further by the conductance curves. To the device with 10 nm PMMA, a third peak took place in optical capacitance and it was due to the storage of electrons by PMMA. Also, the first capacitance peak enhanced approximate linearly as the illumination power increased, which can verify the contribution of the stored charges. Additionally, it shows the potential for the stored charges in optical detections.

Color-Tunable Organic Light Emitting Diodes for Deep Blue Emission by Regulating the Optical Micro-Cavity.

Nowadays, most blue organic light emitting diodes (OLEDs) are fabricated by using sky-blue emitters which are more easily synthesized when compared with other deep blue emitters. Herein, we put forward a new idea of using an optical micro-cavity based on metal electrodes to regulate electroluminance (EL) spectra of sky-blue organic light emitting diodes to obtain a saturated deep blue emission with a narrowed full-width at half-maximum (FWHM). First, we simulate micro-cavity OLEDs and find that the transmission of the anode plays an important role in the forward emission. Meanwhile, the optical path of micro-cavity OLEDs as well as the phase shifting from electrodes influence the EL spectra and induce the extra intensity enhancement. The results show that when the resonant cavity optical path is regulated by changing the thickness of emitting layer (EML) from 25 nm to 75 nm in the micro-cavity, the EL peak of blue OLEDs has a redshift from 479 nm to 493 nm with FWHM shifting from 69.8 nm to 83.2 nm, when compared to the device without the micro-cavity, whose approximate EL peak and FWHM are 487 nm and 87 nm, respectively. However, the efficiency of electroluminescence decreases in micro-cavity OLEDs. We speculate that this is on account of the ohmic contact between ITO and Ag, the surface plasma effect and the rough morphology induced by Ag electrodes.

Concealed expansion of immature precursors underpins acute burst of adult HSC activity in foetal liver.

One day prior to mass emergence of haematopoietic stem cells (HSCs) in the foetal liver at E12.5, the embryo contains only a few definitive HSCs. It is thought that the burst of HSC activity in the foetal liver is underpinned by rapid maturation of immature embryonic precursors of definitive HSCs, termed pre-HSCs. However, because pre-HSCs are not detectable by direct transplantations into adult irradiated recipients, the size and growth of this population, which represents the embryonic rudiment of the adult haematopoietic system, remains uncertain. Using a novel quantitative assay, we demonstrate that from E9.5 the pre-HSC pool undergoes dramatic growth in the aorta-gonad-mesonephros region and by E11.5 reaches the size that matches the number of definitive HSCs in the E12.5 foetal liver. Thus, this study provides for the first time a quantitative basis for our understanding of how the large population of definitive HSCs emerges in the foetal liver.

Enhanced VOC of two-dimensional Ruddlesden-Popper perovskite solar cells using binary synergetic organic spacer cations.

Two-dimensional (2D) Ruddlesden-Popper perovskites (RPPs), with the general formula (RNH3)2An-1BnX3n+1, could realize promising device stability as compared with their three-dimensional counterparts. However, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) with 2D RPPs is relatively low, especially the open circuit voltage (VOC) despite the large band gap of 2D RPPs. Herein, to reduce the VOC losses and enhance the PCE, we propose the use of synergetic organic spacer cations with n-butylammonium (BA+, CH3(CH2)3NH3+) as the major spacer cation and octylammonium (OA+, CH3(CH3)7NH3+) as the additive spacer cation. Scanning electron microscopy reveals that 2D RPP films with mixed organic spacer cations (with a 2 : 0.03 molar ratio of BA : OA in precursor solution) are more uniform and denser. Furthermore, it is found that the 2D RPPs with OA cations exhibit enhanced charge transport by suppressing low-n phases, which is beneficial for high VOC. With the assistance of the OA spacer cation, the VOC is notably increased from 0.94 V to approximately 1.1 V. PSCs with BA-OA 2D RPP achieve the highest PCE of 11.90%, which is higher than that based on pure BA 2D RPP (10.81%). The unencapsulated devices with BA-OA 2D RPPs retain 63% and 93% of their original PCE after being kept in air with a humidity of 30% ± 5% at a room temperature of 20 °C ± 5 °C for 410 h and in a N2 glove box over 1224 h, respectively. This work provides a simple idea for achieving high quality 2D RPP films, and highlights the importance of organic spacer cations in obtaining highly performed PSCs.

Benefits of the Hydrophobic Surface for CH3NH3PbI3 Crystalline Growth Towards Highly Efficient Inverted Perovskite Solar Cells.

In inverted perovskite solar cells (PSCs), high-quality perovskite film grown on hole-transporting material (HTM) with pinhole-free coverage and a large grain size is crucial for high efficiency. Here, we report on the growth of pinhole-free and large grain CH3NH3PbI3 crystals favored by a hydrophobic small molecular HTM, namely, 4,4'-Bis(4-(di-p-toyl)aminostyryl)biphenyl (TPASBP). The hydrophobic surface induced by TPASBP suppressed the density of the perovskite nuclei and heterogeneous nucleation, thus promoting the perovskite to grow into a dense and homogeneous film with a large grain size. The CH3NH3PbI3 deposited on the TPASBP exhibited better crystallization and a lower trap density than that on the hydrophilic surface of indium tin oxide (ITO), resulting in a significant reduction in carrier recombination. Combined with the efficient hole extraction ability of TPASBP, a high efficiency of 18.72% in the inverted PSCs fabricated on TPASBP was achieved.

Developing HSCs become Notch independent by the end of maturation in the AGM region.

The first definitive hematopoietic stem cells (dHSCs) in the mouse emerge in the dorsal aorta of the embryonic day (E) 10.5 to 11 aorta-gonad-mesonephros (AGM) region. Notch signaling is essential for early HSC development but is dispensable for the maintenance of adult bone marrow HSCs. How Notch signaling regulates HSC formation in the embryo is poorly understood. We demonstrate here that Notch signaling is active in E10.5 HSC precursors and involves both Notch1 and Notch2 receptors, but is gradually downregulated while they progress toward dHSCs at E11.5. This downregulation is accompanied by gradual functional loss of Notch dependency. Thus, as early as at final steps in the AGM region, HSCs begin acquiring the Notch independency characteristic of adult bone marrow HSCs as part of the maturation program. Our data indicate that fine stage-dependent tuning of Notch signaling may be required for the generation of definitive HSCs from pluripotent cells.

Facile morphology-controlled synthesis of nickel-coated graphite core-shell particles for excellent conducting performance of polymer-matrix composites and enhanced catalytic reduction of 4-nitrophenol.

We have developed a novel seed-mediated growth method to fabricate nickel-coated graphite composite particles (GP@Ni-CPs) with controllable shell morphology by simply adjusting the concentration of sodium hydroxide ([NaOH]). The fabrication of two kinds of typical GP@Ni-CPs includes adsorption of Ni2+ via electrostatic attraction, sufficient heterogeneous nucleation of Ni atoms by an in situ reduction, and shell-controlled growth by regulating the kinetics of electroless Ni plating in turn. High [NaOH] results in fast kinetics of electroless plating, which causes heterogeneous nuclei to grow isotropically. After fast and uniform growth of Ni nuclei, GP@Ni-CPs with dense shells can be achieved. The first typical GP@Ni-CPs exhibit denser shells, smaller diameters and higher conductivities than the available commercial ones, indicating their important applications in the conducting of polymer-matrix composites. On the other hand, low [NaOH] favors slow kinetics. Thus, the reduction rate of Ni2+ slows down to a relatively low level so that electroless plating is dominated thermodynamically instead of kinetically, leading to an anisotropic crystalline growth of nuclei and finally to the formation of GP@Ni-CPs with nanoneedle-like shells. The second typical samples can effectively catalyze the reduction of p-nitrophenol into p-aminophenol with NaBH4 in comparison with commercial GP@Ni-CPs and RANEY® Ni, owing to the strong charge accumulation effect of needle-like Ni shells. This work proposes a model system for fundamental investigations and has important applications in the fields of electronic interconnection and catalysis.

Runx1 is required for progression of CD41+ embryonic precursors into HSCs but not prior to this.

Haematopoiesis in adult animals is maintained by haematopoietic stem cells (HSCs), which self-renew and can give rise to all blood cell lineages. The AGM region is an important intra-embryonic site of HSC development and a wealth of evidence indicates that HSCs emerge from the endothelium of the embryonic dorsal aorta and extra-embryonic large arteries. This, however, is a stepwise process that occurs through sequential upregulation of CD41 and CD45 followed by emergence of fully functional definitive HSCs. Although largely dispensable at later stages, the Runx1 transcription factor is crucially important during developmental maturation of HSCs; however, exact points of crucial involvement of Runx1 in this multi-step developmental maturation process remain unclear. Here, we have investigated requirements for Runx1 using a conditional reversible knockout strategy. We report that Runx1 deficiency does not preclude formation of VE-cad+CD45-CD41+ cells, which are phenotypically equivalent to precursors of definitive HSCs (pre-HSC Type I) but blocks transition to the subsequent CD45+ stage (pre-HSC Type II). These data emphasise that developmental progression of HSCs during a very short period of time is regulated by precise stage-specific molecular mechanisms.

Distinct Wnt-driven primitive streak-like populations reflect in vivo lineage precursors.

During gastrulation, epiblast cells are pluripotent and their fate is thought to be constrained principally by their position. Cell fate is progressively restricted by localised signalling cues from areas including the primitive streak. However, it is unknown whether this restriction accompanies, at the individual cell level, a reduction in potency. Investigation of these early transition events in vitro is possible via the use of epiblast stem cells (EpiSCs), self-renewing pluripotent cell lines equivalent to the postimplantation epiblast. Strikingly, mouse EpiSCs express gastrulation stage regional markers in self-renewing conditions. Here, we examined the differentiation potential of cells expressing such lineage markers. We show that undifferentiated EpiSC cultures contain a major subfraction of cells with reversible early primitive streak characteristics, which is mutually exclusive to a neural-like fraction. Using in vitro differentiation assays and embryo grafting we demonstrate that primitive streak-like EpiSCs are biased towards mesoderm and endoderm fates while retaining pluripotency. The acquisition of primitive streak characteristics by self-renewing EpiSCs is mediated by endogenous Wnt signalling. Elevation of Wnt activity promotes restriction towards primitive streak-associated lineages with mesendodermal and neuromesodermal characteristics. Collectively, our data suggest that EpiSC pluripotency encompasses a range of reversible lineage-biased states reflecting the birth of pioneer lineage precursors from a pool of uncommitted EpiSCs similar to the earliest cell fate restriction events taking place in the gastrula stage epiblast.

Water-resistant, monodispersed and stably luminescent CsPbBr3/CsPb2Br5 core-shell-like structure lead halide perovskite nanocrystals.

Lead halide perovskite materials are thriving in optoelectronic applications due to their excellent properties, while their instability due to the fact that they are easily hydrolyzed is still a bottleneck for their potential application. In this work, water-resistant, monodispersed and stably luminescent cesium lead bromine perovskite nanocrystals coated with CsPb2Br5 were obtained using a modified non-stoichiometric solution-phase method. CsPb2Br5 2D layers were coated on the surface of CsPbBr3 nanocrystals and formed a core-shell-like structure in the synthetic processes. The stability of the luminescence of the CsPbBr3 nanocrystals in water and ethanol atmosphere was greatly enhanced by the photoluminescence-inactive CsPb2Br5 coating with a wide bandgap. The water-stable enhanced nanocrystals are suitable for long-term stable optoelectronic applications in the atmosphere.