Photoelectric dual-mode triggered phase change materials for all-weather personal thermal management and shape memory.

To cope with the demand of more complex and variable applications, it is urgent to develop dual-mode triggered, breathable, and shape-memory wearable heaters for all-weather personal thermal management of composite phase change materials (PCMs). Herein, after high-temperature carbonization of ZnCo-MOF (metal-organic framework) nanosheet array grown in situ on flexible and breathable carbon cloth (CC) and subsequent encapsulation of polyethylene glycol (PEG), the as-prepared PEG/CC@Co/CNT (carbon nanotube) composite PCMs exhibited good breathability, mechanical strength (tensile strength of 9.15 MPa), thermal energy storage density (114.19 J/g), and shape memory due to the synergy of flexible CC skeleton and rigid PEG. More importantly, composite PCMs possessed excellent solar-thermal (93.7 %, 100 mW/cm2) and electro-thermals (94.5 %, 2.0 V) conversion and storage capacity, benefiting from the conjugation effect of high graphitized carbon/carbon heterostructure with fast electron/photon/phonon transmission and the localized surface plasmon resonance effect of Co nanoparticles. Therefore, the integration of solar heating and Joule heating into breathable composite PCMs can be accurately used for next-generation all-weather, all-season, dual-mode triggered personal thermal management, including indoor/outdoor, daytime/night, rainy/cloudy and other complex and changeable scenarios.

An Exploratory Pilot Study on the Application of Radiofrequency Ablation for Atrial Fibrillation Guided by Computed Tomography-Based 3D Printing Technology.

Radiofrequency ablation (RFA) is the treatment of choice for atrial fibrillation (AF). Additionally, the utilization of 3D printing for cardiac models offers an in-depth insight into cardiac anatomy and cardiovascular diseases. The study aims to evaluate the clinical utility and outcomes of RFA following in vitro visualization of the left atrium (LA) and pulmonary vein (PV) structures via 3D printing (3DP). Between November 2017 and April 2021, patients who underwent RFA at the First Affiliated Hospital of Xinxiang Medical University were consecutively enrolled and randomly allocated into two groups: the 3DP group and the control group, in a 1:1 ratio. Computed tomography angiography (CTA) was employed to capture the morphology and diameter of the LA and PV, which facilitated the construction of a 3D entity model. Additionally, surgical procedures were simulated using the 3D model. Parameters such as the duration of the procedure, complications, and rates of RFA recurrence were meticulously documented. Statistical analysis was performed using the t-test or Mann-Whitney U test to evaluate the differences between the groups, with a P-value of less than 0.05 considered statistically significant. In this study, a total of 122 patients were included, with 53 allocated to the 3DP group and 69 to the control group. The analysis of the morphological measurements of the LA and PV taken from the workstation or direct entity measurement showed no significant difference between the two groups (P > 0.05). However, patients in the 3DP group experienced significantly shorter RFA times (97.03 ± 28.39 compared to 120.51 ± 44.76 min, t = 3.05, P = 0.003), reduced duration of radiation exposure (2.55 [interquartile range 2.01, 3.24] versus 3.20 [2.28, 3.91] min, Z = 3.23, P < 0.001), and shorter modeling times (7.68 ± 1.03 compared to 8.89 ± 1.45 min, t = 5.38, P < 0.001). 3DP technology has the potential to enhance standard RFA practices by reducing the time required for intraoperative interventions and exposure to radiation.

The safety and efficacy of emergency stenting during bridging therapy: A Single-Center Retrospective Study.

INTRODUCTION: To investigated the safety and efficacy of emergency stenting for patients with ischemic stroke treated with bridging therapy. METHODS: Patients with onset of stroke who underwent bridging therapy were included in the two groups with emergency stenting (ESG) and without stenting (NSG). To avoid the bias due to confounding variables, subjects were further assigned in two groups using 1:1 propensity score matching (PSM). The safety outcomes include the incidence of intracranial hemorrhage (ICH), parenchymal hemorrhage type 2 (PH2), symptomatic intracranial hemorrhage (sICH), fatal hemorrhage, and mortality. The efficacy outcomes include successful recanalization, three-month favorable outcome (modified Rankin Scale [mRS]: 0-2). RESULTS: 175 patients treated with bridging therapy were included in this study, with 52 patients in the ES group and 123 patients in the groups without ES, and with 30 patients in each group after PSM. No significant differences in the incidences of ICH, PH2, sICH, fatal hemorrhage, and mortality were found between the two groups with ES and without ES before and after PSM (P>0.05 for all groups). The analysis without PSM showed that the group with ES had a higher rate of successful recanalization (98.1% vs. 81.6%，P=0.041) than the group without ES, but no significant difference was seen (96.6% vs. 93.3%，P=0.554) between the two groups after PSM. There was no difference in favorable outcome between the two groups before and after matching as well (P>0.05). CONCLUSIONS: It is safe and effective for patients with onset of ischemic stroke to receive emergency stenting during bridging therapy, without increasing the risk of hemorrhagic transformation and mortality.

Refining Perovskite Heterojunctions for Effective Light-Emitting Solar Cells.

Solar cells capable of light-harvesting during daytime and light-emission at night are multifunctional semiconductor devices with many potential applications. Here, it is reported that halide perovskite heterojunction interfaces can be refined to yield stable and efficient solar cells. The cell can also operate effectively as an ultralow-voltage light-emitting diode (LED) with a peak external quantum efficiency of electroluminescence (EQEEL ) of 3.3%. Spectroscopic and microscopic studies reveal that double-heterojunction refinement with wide-bandgap salts is key to densifying the packing of perovskite grains and enlarging the bandgaps of the perovskite surfaces that are in contact with charge-transport semiconductors. The refined perovskite enables a simple device with dual actions of solar cells and LEDs. This type of all-in-one device has the potential to be used in multifunctional harvesting-storage-utilization (HSU) systems.

Is it feasible to measure pulmonary vein data using volume rendering images?

BACKGROUND: Pulmonary vein (PV) data are commonly measured on multiplanar image reformation (MPR) images and volume rendering (VR) images. PURPOSE: To compared and analyze the advantages and disadvantages of PV data based on VR images and MPR images. MATERIAL AND METHODS: A total of 94 patients with atrial fibrillation (AF) with imaging data were included in the study. The respective image postprocessing time and the three surgical interventionists' preferences for the two images were recorded. A paired t-test or chi-square test was used to compare their difference, and P < 0.05 was considered statistically significant. RESULTS: There was no statistically significant difference between the data values including the maximal and minimal ostial diameters of the left superior PV (LSPV), the left inferior PV (LIPV), the right superior PV (RSPV), and the right inferior PV (RIPV) obtained by VR and MPR images (P > 0.05). Yet, the mean postprocessing time of VR images (15.10 ± 3.05 min) was shorter compared to MPR images (16.54 ± 2.60 min) (t = 22.84, P < 0.05). All three surgical interventionists preferred VR images (accounted for 85.1%, 86.2%, and 84.0%, respectively), and there was no statistical difference in the degree of image preference among the three (chi-square = 0.596, P = 0.963). CONCLUSION: PV data measurement could be performed on both VR and MRP images; however, the data on VR images were more intuitive and more accessible for interventional surgeons.

Development of a Three-Dimensional Multi-Modal Perfusion-Thermal Electrode System for Complete Tumor Eradication.

Background: Residual viable tumor cells after ablation at the tumor periphery serve as the source for tumor recurrence, leading to treatment failure. Purpose: To develop a novel three-dimensional (3D) multi-modal perfusion-thermal electrode system completely eradicating medium-to-large malignancies. Materials and Methods: This study included five steps: (i) design of the new system; (ii) production of the new system; (iii) ex vivo evaluation of its perfusion-thermal functions; (iv) mathematic modeling and computer simulation to confirm the optimal temperature profiles during the thermal ablation process, and; (v) in vivo technical validation using five living rabbits with orthotopic liver tumors. Results: In ex vivo experiments, gross pathology and optical imaging demonstrated the successful spherical distribution/deposition of motexafin gadolinium administered through the new electrode, with a temperature gradient from the electrode core at 80 °C to its periphery at 42 °C. An excellent repeatable correlation of temperature profiles at varying spots, from the center to periphery of the liver tumor, was found between the mathematic simulation and actual animal tumor models (Pearson coefficient ≥0.977). For in vivo validation, indocyanine green (ICG) was directly delivered into the peritumoral zones during simultaneous generation of central tumoral lethal radiofrequency (RF) heat (>60 °C) and peritumoral sublethal RF hyperthermia (<60 °C). Both optical imaging and fluorescent microscopy confirmed successful peritumoral ICG distribution/deposition with increased heat shock protein 70 expression. Conclusion: This new 3D, perfusion-thermal electrode system provided the evidence on the potential to enable simultaneous delivery of therapeutic agents and RF hyperthermia into the difficult-to-treat peritumoral zones, creating a new strategy to address the critical limitation, i.e., the high incidence of residual and recurrent tumor following thermal ablation of unresectable medium-to-large and irregular tumors.

[Retracted] IL­33 attenuates cardiac remodeling following myocardial infarction via inhibition of the p38 MAPK and NF­κB pathways.

An interested reader of an article published in the journal Circulation Research [Krishnamurthy P, Rajasingh J, Lambers E, Qin G, Losordo DW and Kishore R: L­10 inhibits inflammation and attenuates left ventricular remodeling after myocardial infarction via activation of STAT3 and suppression of HuR. Circ Res 104: e9­18, 2008] drew to our attention that data featured in their paper had appeared subsequently in the abovementioned article by Yin et al in Molecular Medicine Reports in 2014. Specifically, Fig. 1 in the Mol Med Rep paper included the same histograms as those featured in Fig. 2 in the Circ Res paper; Fig. 2 in the Mol Med Rep paper contained data derived from Fig. 1 in the Circ Res paper; and Figs. 3­5 in both papers shared a substantial amount of the same data. Following an internal investigation, the Journal was able to confirm that this accusation of plagiarism was well­founded. On those grounds, the Editor of Molecular Medicine Reports has decided to retract this paper. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor deeply regrets the grievance that this matter has caused to the authors of the previously published article, and also any inconvenience caused to the readership of the Journal.

Comparing the Conventional and Balloon-Guided Catheter-Assisted SWIM Technology for the Treatment of Acute Ischemic Stroke.

Objective: Acute ischemic stroke is common in elder patients. This study investigates whether using the balloon-guided catheter (BGC) would improve the effect of stent thrombectomy (Solitaire FR With Intracranial Support Catheter for Mechanical Thrombectomy, SWIM) for patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO). Method: The data of 209 patients with AIS-LVO underwent SWIM were collected retrospectively from January 2017 to June 2021. These patients were divided into two groups based on whether they used of BGC or not. The propensity score matching (PSM) analysis was used to compare the differences in the first pass effect (FPE), successful recanalization, embolus escape rate, symptomatic intracranial hemorrhage (sICH), 90-day clinical favorable outcome, 90-day all-cause mortality, and complications in the patients treated with SWIM combined with balloon-guided catheter or conventional catheter. Results: Among the 209 patients, 44 patients were treated with BGC and 165 patients were not. After matching, a total of 111 patients were included. The results showed that there was no statistical difference in FPE (35.1% in non-BGC group compared to 24.3% in BGC group, matched RR, 0.59; 95% CI, 0.24-1.44), successful recanalization (89.2 vs. 91.9%, matched RR, 1.37; 95%CI, 0.34-5.51), embolus escape (6.8 vs. 8.1%, matched RR, 1.22; 95%CI, 0.28-5.40), sICH (8.1 vs. 13.5%; matched RR, 1.77; 95%CI 0.50-6.24), 90-day clinical favorable outcome (48.7 vs. 54.1%, matched RR, 1.11; 95%CI 0.51-2.46), 90-day all-cause mortality (17.6 vs. 21.6%, matched RR, 1.29; 95%CI 0.48-3.47), and the incidence of complications (6.8 vs. 5.4%, matched RR, 0.79 95%CI 0.15-4.27). These results indicate that using SWIM as the first-line treatment for patients with AIS-LVO, there is no statistical significance in FPE, final successful recanalization, distal emboli, sICH, procedural time, 90-day favorable outcome, 90-day mortality, and complications with or without BGC. Conclusion: Balloon-guided catheter does not affect the result of using SWIM as the first-line treatment for patients with AIS-LVO. Our results will guide daily practice, with the adoption of the use of a guided catheter without a balloon.

Fast Near-Infrared Photodetection Using III-V Colloidal Quantum Dots.

Colloidal quantum dots (CQDs) are promising materials for infrared (IR) light detection due to their tunable bandgap and their solution processing; however, to date, the time response of CQD IR photodiodes is inferior to that provided by Si and InGaAs. It is reasoned that the high permittivity of II-VI CQDs leads to slow charge extraction due to screening and capacitance, whereas III-Vs-if their surface chemistry can be mastered-offer a low permittivity and thus increase potential for high-speed operation. In initial studies, it is found that the covalent character in indium arsenide (InAs) leads to imbalanced charge transport, the result of unpassivated surfaces, and uncontrolled heavy doping. Surface management using amphoteric ligand coordination is reported, and it is found that the approach addresses simultaneously the In and As surface dangling bonds. The new InAs CQD solids combine high mobility (0.04 cm2 V-1 s-1 ) with a 4× reduction in permittivity compared to PbS CQDs. The resulting photodiodes achieve a response time faster than 2 ns-the fastest photodiode among previously reported CQD photodiodes-combined with an external quantum efficiency (EQE) of 30% at 940 nm.

Distribution control enables efficient reduced-dimensional perovskite LEDs.

Light-emitting diodes (LEDs) based on perovskite quantum dots have shown external quantum efficiencies (EQEs) of over 23% and narrowband emission, but suffer from limited operating stability1. Reduced-dimensional perovskites (RDPs) consisting of quantum wells (QWs) separated by organic intercalating cations show high exciton binding energies and have the potential to increase the stability and the photoluminescence quantum yield2,3. However, until now, RDP-based LEDs have exhibited lower EQEs and inferior colour purities4-6. We posit that the presence of variably confined QWs may contribute to non-radiative recombination losses and broadened emission. Here we report bright RDPs with a more monodispersed QW thickness distribution, achieved through the use of a bifunctional molecular additive that simultaneously controls the RDP polydispersity while passivating the perovskite QW surfaces. We synthesize a fluorinated triphenylphosphine oxide additive that hydrogen bonds with the organic cations, controlling their diffusion during RDP film deposition and suppressing the formation of low-thickness QWs. The phosphine oxide moiety passivates the perovskite grain boundaries via coordination bonding with unsaturated sites, which suppresses defect formation. This results in compact, smooth and uniform RDP thin films with narrowband emission and high photoluminescence quantum yield. This enables LEDs with an EQE of 25.6% with an average of 22.1 ±1.2% over 40 devices, and an operating half-life of two hours at an initial luminance of 7,200 candela per metre squared, indicating tenfold-enhanced operating stability relative to the best-known perovskite LEDs with an EQE exceeding 20%1,4-6.

LncRNA PVT1 knockdown alleviated ox-LDL-induced vascular endothelial cell injury and atherosclerosis by miR-153-3p/GRB2 axis via ERK/p38 pathway.

BACKGROUND AND AIMS: LncRNA plasmacytoma variant translocation 1 (PVT1) plays a regulatory role in some cardiovascular diseases, but its role in atherosclerosis (AS) remains barely explored. The study aimed to investigate the effects of PVT1 on high fat diet-induced AS and its potential mechanisms. METHODS AND RESULTS: ApoE -/- mice were fed with high fat diet for 8 weeks to establish an AS model. Lentiviral vectors containing PVT1 short hairpin RNA (PVT1-shRNA) or NC-shRNA were administered by tail vein injection. Cell viability, apoptosis, inflammatory factor secretion, and cellular oxidative stress were measured to evaluate oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cell (HUVEC) injury. Dual-luciferase reporter gene and RNA immunoprecipitation assays were used to confirm the interaction between miR-153-3p and PVT1 or growth factor receptor binding protein 2 (GRB2). Atherosclerotic lesions, lipid deposition, and cell apoptosis in aorta were analyzed by H&E, Oil Red O, and TUNEL straining. PVT1 knockdown alleviated ox-LDL-induced inflammation, apoptosis and oxidative stress in HUVECs. PVT1 acted as a sponge of miR-153-3p, and GRB2 was confirmed as a target of miR-153-3p. MiR-153-3p overexpression attenuated the enhanced effects of PVT1 on ox-LDL-induced cell damage. GRB2 overexpression reversed the mitigating effects of miR-153-3p on ox-LDL-caused injury. Inhibiting PVT1 restrained the activation of ERK1/2 and p38 pathway via miR-153-3p/GRB2 axis. Additionally, silencing PVT1 in vivo reduced atherosclerotic plaques, lipid deposition, inflammation, oxidative stress, and apoptosis in AS mice. CONCLUSION: PVT1 knockdown alleviated ox-LDL-induced vascular endothelial cell injury and atherosclerosis through miR-153-3p/GRB2 axis via ERK1/2 and p38 pathway.

Image-Guided Peri-Tumoral Radiofrequency Hyperthermia-Enhanced Direct Chemo-Destruction of Hepatic Tumor Margins.

PURPOSE: To validate the feasibility of using peri-tumoral radiofrequency hyperthermia (RFH)-enhanced chemotherapy to obliterate hepatic tumor margins. METHOD AND MATERIALS: This study included in vitro experiments with VX2 tumor cells and in vivo validation experiments using rabbit models of liver VX2 tumors. Both in vitro and in vivo experiments received different treatments in four groups (n=6/group): (i) RFH-enhanced chemotherapy consisting of peri-tumoral injection of doxorubicin plus RFH at 42°C; (ii) RFH alone; (iii) doxorubicin alone; and (iv) saline. Therapeutic effect on cells was evaluated using different laboratory examinations. For in vivo experiments, orthotopic hepatic VX2 tumors in 24 rabbits were treated by using a multipolar radiofrequency ablation electrode, enabling simultaneous delivery of both doxorubicin and RFH within the tumor margins. Ultrasound imaging was used to follow tumor growth overtime, correlated with subsequent histopathological analysis. RESULTS: In in vitro experiments, MTS assay demonstrated the lowest cell proliferation, and apoptosis analysis showed the highest apoptotic index with RFH-enhanced chemotherapy, compared with the other three groups (p<0.01). In in vivo experiments, ultrasound imaging detected the smallest relative tumor volume with RFH-enhanced chemotherapy (p<0.01). The TUNEL assay further confirmed the significantly increased apoptotic index and decreased cell proliferation in the RFH-enhanced therapy group (p<0.01). CONCLUSION: This study demonstrates that peri-tumoral RFH can specifically enhance the destruction of tumor margins in combination with peri-tumoral injection of a chemotherapeutic agent. This new interventional oncology technique may address the critical clinical problem of frequent marginal tumor recurrence/persistence following thermal ablation of large (>3 cm) hepatic cancers.

All-Inorganic Quantum-Dot LEDs Based on a Phase-Stabilized α-CsPbI3 Perovskite.

The all-inorganic nature of CsPbI3 perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI3 films; however, these strategies-including strain and doping-are based on organic-ligand-capped perovskites, which prevent perovskites from forming the close-packed quantum dot (QD) solids necessary to achieve high charge and thermal transport. We developed an inorganic ligand exchange that leads to CsPbI3 QD films with superior phase stability and increased thermal transport. The atomic-ligand-exchanged QD films, once mechanically coupled, exhibit improved phase stability, and we link this to distributing strain across the film. Operando measurements of the temperature of the LEDs indicate that KI-exchanged QD films exhibit increased thermal transport compared to controls that rely on organic ligands. The LEDs exhibit a maximum EQE of 23 % with an electroluminescence emission centered at 640 nm (FWHM: ≈31 nm). These red LEDs provide an operating half-lifetime of 10 h (luminance of 200 cd m-2 ) and an operating stability that is 6× higher than that of control devices.

Enhanced CO2 Photocatalysis by Indium Oxide Hydroxide Supported on TiN@TiO2 Nanotubes.

Herein is developed a ternary heterostructured catalyst, based on a periodic array of 1D TiN nanotubes, with a TiO2 nanoparticulate intermediate layer and a In2O3-x(OH)y nanoparticulate shell for improved performance in the photocatalytic reverse water gas shift reaction. It is demonstrated that the ordering of the three components in the heterostructure sensitively determine its activity in CO2 photocatalysis. Specifically, TiN nanotubes not only provide a photothermal driving force for the photocatalytic reaction, owing to their strong optical absorption properties, but they also serve as a crucial scaffold for minimizing the required quantity of In2O3-x(OH)y nanoparticles, leading to an enhanced CO production rate. Simultaneously, the TiO2 nanoparticle layer supplies photogenerated electrons and holes that are transferred to active sites on In2O3-x(OH)y nanoparticles and participate in the reactions occurring at the catalyst surface.

Plasmonic Titanium Nitride Facilitates Indium Oxide CO2 Photocatalysis.

Nanoscale titanium nitride TiN is a metallic material that can effectively harvest sunlight over a broad spectral range and produce high local temperatures via the photothermal effect. Nanoscale indium oxide-hydroxide, In2 O3- x (OH)y , is a semiconducting material capable of photocatalyzing the hydrogenation of gaseous CO2 ; however, its wide electronic bandgap limits its absorption of photons to the ultraviolet region of the solar spectrum. Herein, the benefits of both nanomaterials in a ternary heterostructure: TiN@TiO2 @In2 O3- x (OH)y are combined. This heterostructured material synergistically couples the metallic TiN and semiconducting In2 O3- x (OH)y phases via an interfacial semiconducting TiO2 layer, allowing it to drive the light-assisted reverse water gas shift reaction at a conversion rate greatly surpassing that of its individual components or any binary combinations thereof.

Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites.

It remains a central challenge to the information display community to develop red light-emitting diodes (LEDs) that meet demanding color coordinate requirements for wide color gamut displays. Here, we report high-efficiency, lead-free (PEA)2SnI4 perovskite LEDs (PeLEDs) with color coordinates (0.708, 0.292) that fulfill the Rec. 2100 specification for red emitters. Using valeric acid (VA)-which we show to be strongly coordinated to Sn2+-we slow the crystallization rate of the perovskite, improving the film morphology. The incorporation of VA also protects tin from undesired oxidation during the film-forming process. The improved films and the reduced Sn4+ content enable PeLEDs with an external quantum efficiency of 5% and an operating half-life exceeding 15 hours at an initial brightness of 20 cd/m2 This work illustrates the potential of Cd- and Pb-free PeLEDs for display technology.

Colloidal Quantum Dot Bulk Heterojunction Solids with Near-Unity Charge Extraction Efficiency.

Colloidal quantum dots (CQDs) are of interest for optoelectronic applications owing to their tunable properties and ease of processing. Large-diameter CQDs offer optical response in the infrared (IR), beyond the bandgap of c-Si and perovskites. The absorption coefficient of IR CQDs (≈104 cm-1) entails the need for micrometer-thick films to maximize the absorption of IR light. This exceeds the thickness compatible with the efficient extraction of photogenerated carriers, a fact that limits device performance. Here, CQD bulk heterojunction solids are demonstrated that, with extended carrier transport length, enable efficient IR light harvesting. An in-solution doping strategy for large-diameter CQDs is devised that addresses the complex interplay between (100) facets and doping agents, enabling to control CQD doping, energetic configuration, and size homogeneity. The hetero-offset between n-type CQDs and p-type CQDs is manipulated to drive the transfer of electrons and holes into distinct carrier extraction pathways. This enables to form active layers exceeding thicknesses of 700 nm without compromising open-circuit voltage and fill factor. As a result, >90% charge extraction efficiency across the ultraviolet to IR range (350-1400 nm) is documented.

Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots.

Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids-necessary for device fabrication-requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V-1 s-1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%.

High Color Purity Lead-Free Perovskite Light-Emitting Diodes via Sn Stabilization.

Perovskite-based light-emitting diodes (PeLEDs) are now approaching the upper limits of external quantum efficiency (EQE); however, their application is currently limited by reliance on lead and by inadequate color purity. The Rec. 2020 requires Commission Internationale de l'Eclairage coordinates of (0.708, 0.292) for red emitters, but present-day perovskite devices only achieve (0.71, 0.28). Here, lead-free PeLEDs are reported with color coordinates of (0.706, 0.294)-the highest purity reported among red PeLEDs. The variation of the emission spectrum is also evaluated as a function of temperature and applied potential, finding that emission redshifts by <3 nm under low temperature and by <0.3 nm V-1 with operating voltage. The prominent oxidation pathway of Sn is identified and this is suppressed with the aid of H3PO2. This strategy prevents the oxidation of the constituent precursors, through both its moderate reducing properties and through its forming complexes with the perovskite that increase the energetic barrier toward Sn oxidation. The H3PO2 additionally seeds crystal growth during film formation, improving film quality. PeLEDs are reported with an EQE of 0.3% and a brightness of 70 cd m-2; this is the record among reported red-emitting, lead-free PeLEDs.