Interfacial Heterojunction Enables High Efficient PbS Quantum Dot Solar Cells.

Colloidal quantum dots (CQDs) are promising optoelectronic materials for solution-processed thin film optoelectronic devices. However, the large surface area with abundant surface defects of CQDs and trap-assisted non-radiative recombination losses at the interface between CQDs and charge-transport layer limit their optoelectronic performance. To address this issue, an interface heterojunction strategy is proposed to protect the CQDs interface by incorporating a thin layer of polyethyleneimine (PEIE) to suppress trap-assisted non-radiative recombination losses. This thin layer not only acts as a protective barrier but also modulates carrier recombination and extraction dynamics by forming heterojunctions at the buried interface between CQDs and charge-transport layer, thereby enhancing the interface charge extraction efficiency. This enhancement is demonstrated by the shortened lifetime of carrier extraction from 0.72 to 0.46 ps. As a result, the resultant PbS CQD solar cells achieve a power-conversion-efficiency (PCE) of 13.4% compared to 12.2% without the heterojunction.

In situcell-scale probing nucleation, growth and evolution of CsPbBr3nanowires by optical absorption spectroscopy.

The growth kinetics of colloidal lead halide perovskite nanomaterials are an integral part of their applications, remains poorly understood due to complex nucleation processes and lack ofin situsize monitoring method. Here we demonstrated that absorption spectra can be used to observein situgrowth processes of ultrathin CsPbBr3nanowires in solution with reference to the effective mass infinite deep square potential well model. By means of this method, we have found that the ultrathin nanowires, fabricated by hot injection method, were firstly formed within one minute. Subsequently, they merge with each other into a thicker structure with increasing reaction time. We revealed that the nucleation, growth, and merging of the CsPbBr3nanowires are determined by the acid concentration and ligand chain length. At lower acidity, the critical nucleation size of the nanowire is smaller, while the shorter the ligand chain length, the faster the merging among the nanowires. Moreover, the merging mode between nanowires changed with their nucleation size. This growth kinetics of CsPbBr3nanowires provides a reference for optimizing the synthesis conditions to obtain the one-dimensional CsPbBr3with desired size, thus enabling accurate control of the nanowire shape.

Selective anchoring of Pt NPs on covalent triazine-based frameworks via in situ derived bridging ligands for boosting photocatalytic hydrogen evolution.

The efficient and stable production of hydrogen (H2) through Pt-containing photocatalysts remains a great challenge. Herein, we develop an effective strategy to selectively and uniformly anchor Pt NPs (∼1.2 nm) on a covalent triazine-based framework photocatalyst via in situ derived bridging ligands. Compared to Pt/CTF-1, the obtained Pt/AT-CTF-1 exhibits a considerable photocatalytic H2 evolution rate of 562.9 µmol g-1 h-1 under visible light irradiation. Additionally, the strong interaction between the Pt NPs and in situ derived bridging ligands provides remarkable stability to Pt/AT-CTF-1. Experimental investigations and photo/chemical characterization reveal the synergy of the in situ derived bridging ligands in Pt/AT-CTF-1, which can selectively anchor the Pt NPs with homogeneous sizes and efficiently improve the transmission of charge carriers. This work provides a new perspective toward stabilizing ultrasmall nanoclusters and facilitating electron transfer in photocatalytic H2 evolution materials.

Multifunctional ytterbium oxide buffer for perovskite solar cells.

Perovskite solar cells (PSCs) comprise a solid perovskite absorber sandwiched between several layers of different charge-selective materials, ensuring unidirectional current flow and high voltage output of the devices1,2. A 'buffer material' between the electron-selective layer and the metal electrode in p-type/intrinsic/n-type (p-i-n) PSCs (also known as inverted PSCs) enables electrons to flow from the electron-selective layer to the electrode3-5. Furthermore, it acts as a barrier inhibiting the inter-diffusion of harmful species into or degradation products out of the perovskite absorber6-8. Thus far, evaporable organic molecules9,10 and atomic-layer-deposited metal oxides11,12 have been successful, but each has specific imperfections. Here we report a chemically stable and multifunctional buffer material, ytterbium oxide (YbOx), for p-i-n PSCs by scalable thermal evaporation deposition. We used this YbOx buffer in the p-i-n PSCs with a narrow-bandgap perovskite absorber, yielding a certified power conversion efficiency of more than 25%. We also demonstrate the broad applicability of YbOx in enabling highly efficient PSCs from various types of perovskite absorber layer, delivering state-of-the-art efficiencies of 20.1% for the wide-bandgap perovskite absorber and 22.1% for the mid-bandgap perovskite absorber, respectively. Moreover, when subjected to ISOS-L-3 accelerated ageing, encapsulated devices with YbOx exhibit markedly enhanced device stability.

Buried-Metal-Grid Electrodes for Efficient Parallel-Connected Perovskite Solar Cells.

The limited conductivity of existing transparent conducting oxide (TCO) greatly restricts the further performance improvement of perovskite solar cells (PSCs), especially for large-area devices. Herein, buried-metal-grid tin-doped indium oxide (BMG ITO) electrodes are developed to minimize the power loss caused by the undesirable high sheet resistance of TCOs. By burying 140-nm-thick metal grids into ITO using a photolithography technique, the sheet resistance of ITO is reduced from 15.0 to 2.7 Ω sq-1 . The metal step of BMG over ITO has a huge impact on the charge carrier transport in PSCs. The PSCs using BMG ITO with a low metal step deliver power conversion efficiencies (PCEs) significantly better than that of their counterparts with higher metal steps. Moreover, compared with the pristine ITO-based PSCs, the BMG ITO-based PSCs show a smaller PCE decrease when scaling up the active area of devices. The parallel-connected large-area PSCs with an active area of 102.8 mm2 reach a PCE of 22.5%. The BMG ITO electrodes are also compatible with the fabrication of inverted-structure PSCs and organic solar cells. The work demonstrates the great efficacy of improving the conductivity of TCO by BMG and opens up a promising avenue for constructing highly efficient large-area PSCs.

Selective Shielding of the (002) Plane Enabling Vertically Oriented Zinc Plating for Dendrite-Free Zinc Anode.

Uncontrolled growth of Zn dendrites hinders the future development of aqueous Zn-ion batteries. Despite that the (100) plane possesses better zincophilic ability and fast kinetics, dendrites are generally suppressed via (002) plane-oriented Zn deposition in previous reports; the ordered (100) plane-dominant Zn deposition, especially under high current density has not yet been realized. Herein, vertically-oriented Zn plating with preferential growth of (100) plane is reported using disodium lauryl phosphate (DLP) as an electrolyte additive. DLP is preferentially anchored on the Zn (002) crystal plane via the polar phosphate group, then the deposition of Zn atoms on the (002) plane is retarded by the long alkyl chain, finally promoting the preferred growth of the (100) plane. This unique growth pattern results in ultrastable Zn plating/stripping at a super-high current density of 50 mA cm-2 , with a cumulative capacity of 8500 mAh cm-2 . The Zn//Zn symmetric cell also cycles steadily for 700 h with a large areal capacity of 10 mAh cm-2 at a current density of 10 mA cm-2 . This study provides new insights into the realization of dendrite-free Zn anodes by crystal plane modulation.

Effect of vane angle on turbulence-chemistry interactions, temperature, flow field, burnout, and NOx emissions in swirling flames fueled by semicoke mixtures.

To enhance the combustion efficiency and reduce NOx emissions in large-scale semicoke and bituminous coal blends, an extensive numerical study was conducted. The focus of this study was to optimize the quaternary air vane angle (αv) through detailed analysis of the temperature and flow fields, turbulence-chemistry interactions, char burnout, and NOx formation in a carefully scaled 1:5 dual-swirl burner. The results showed that with increasing αv, the high-temperature flame region was narrowed and the peak temperature was reduced along with the broadened inner recirculation zone and the shrunken external recirculation zone due to better pulverized fuel-oxidant blending and reinforced convective heat transfer. The peak turbulent Damköhler number Dat evidently increased from 197.5 to 496 with increasing αv, which implied a strengthened homogeneous combustion. Additionally, the corresponding mixing time scales increased while the chemical kinetics time scales decreased, which denoted that an intense diffusing flame was generated with a strong turbulent intensity. The peak heterogeneous Damköhler number Das-O2 showed a reduction from 2.54 to 2.27, while the peak values of Das-CO2 and Das-H2O decreased from 0.1 to 0.077 and from 0.02 to 0.015, respectively. The char-O2 reaction was controlled by diffusion/kinetics; both char-CO2 and char-H2O reactions were determined by kinetics, and all gas‒solid reactions showed a kinetically controlled regime. With increasing αv, the enlarged inner recirculation region increased the residence time, and a higher dilution level lessened the peak temperature, which led to reductions in fuel-NOx and the thermal-NOx. The αv range of 30-45° (or swirl number Sn = 0.55-0.95) was suggested by taking the high burnout and low-NOx formation into account.

Influence of Volatile Organic Compound Adsorption on the Characteristics of Organic Field-Effect Transistors and Rules for Gas-Sensing Measurements.

Owing to the advantages of organic field-effect transistors (OFETs) in the versatility of organic synthesis, multiparameter measurement, and signal amplification, sensors based on OFETs have received increasing attention for detecting volatile organic compounds (VOCs). However, false device operation and gas-sensing measurements often occur to vitiate the advantages of OFETs and even output error gas-sensing signals. In this work, by experimentally and theoretically studying the effects of VOC adsorption on the operational characteristics of the OFET, the proper operations of OFETs in gas-sensing measurements were clarified. The multiparameter measurements of OFETs showed that the source-drain current was the optimized parameter for achieving high responsivity, and other OFET parameters could be used for fingerprint analysis. By operating OFETs in the near-threshold region, the amplification effect was switched to enhance the responsivity by orders of magnitude to VOCs, while in the overthreshold region, the OFETs had a low signal-to-noise ratio. Besides, a counteraction effect and an uncertainty effect were discovered, leading to error gas-sensing signals. A theoretical study was carried out to reveal the dependency of the gas-sensing properties of OFETs on VOC adsorption. A series of rules were proposed for guiding the measurements of OFET sensors by taking full advantage of transistors in gas-sensing applications.

A high-performance, all-solid-state Na+ selective sensor printed with eco-friendly conductive ink.

In recent years, the integration of flexible printed electronics and electrochemical sensors has emerged as a new approach for developing wearable biochemical detecting devices. Among the materials utilized in flexible printed electronics, carbon-based conductive inks are considered to be crucial. In this study, we propose a cost-effective, highly conductive, and environmentally friendly ink formulation utilizing graphite and carbon black (CB) as conductive fillers, resulting in a very low sheet resistance of 15.99 Ω sq-1 (conductivity of 2.5 × 103 S m-1) and a printed film thickness of 25 µm. The unique "sandwich" structure of the working electrode (WE) printed with this ink enhances its electrical conductivity, leading to high sensitivity, selectivity, and stability, with almost no water film generated between the WE and the ion-selective membrane (ISM), strong ion selectivity, long-term stability, and anti-interference. The lower detection limit of the sensor for Na+ is 0.16 mM with a slope of 75.72 mV per decade. To validate the sensor's usability, we analyzed three sweat samples collected during physical activity, with Na+ concentrations within the typical range for human sweat (51 ± 4 mM, 39 ± 5 mM, and 46 ± 2 mM).

Dietary sodium enhances the expression of SLC4 family transporters, IRBIT, L-IRBIT, and PP1 in rat kidney: Insights into the molecular mechanism for renal sodium handling.

The kidney plays a central role in maintaining the fluid and electrolyte homeostasis in the body. Bicarbonate transporters NBCn1, NBCn2, and AE2 are expressed at the basolateral membrane of the medullary thick ascending limb (mTAL). In a previous study, NBCn1, NBCn2, and AE2 are proposed to play as a regulatory pathway to decrease NaCl reabsorption in the mTAL under high salt condition. When heterologously expressed, the activity of these transporters could be stimulated by the InsP3R binding protein released with inositol 1,4,5-trisphosphate (IRBIT), L-IRBIT (collectively the IRBITs), or protein phosphatase PP1. In the present study, we characterized by immunofluorescence the expression and localization of the IRBITs, and PP1 in rat kidney. Our data showed that the IRBITs were predominantly expressed from the mTAL through the distal renal tubules. PP1 was predominantly expressed in the TAL, but is also present in high abundance from the distal convoluted tubule through the medullary collecting duct. Western blotting analyses showed that the abundances of NBCn1, NBCn2, and AE2 as well as the IRBITs and PP1 were greatly upregulated in rat kidney by dietary sodium. Co-immunoprecipitation study provided the evidence for protein interaction between NBCn1 and L-IRBIT in rat kidney. Taken together, our data suggest that the IRBITs and PP1 play an important role in sodium handling in the kidney. We propose that the IRBITs and PP1 stimulates NBCn1, NBCn2, and AE2 in the basolateral mTAL to inhibit sodium reabsorption under high sodium condition. Our study provides important insights into understanding the molecular mechanism for the regulation of sodium homeostasis in the body.

P2Y1 receptor in the colonic submucosa of rats and its association with opioid­induced constipation.

The aim of the present study was to explore the expression changes of P2Y purinergic receptor 1 (P2Y1) in the distal colonic submucosa of opioid-induced constipation (OIC) rats and its association with the occurrence of OIC, an OIC rat model was generated by intraperitoneal injection of loperamide hydrochloride, a selective agonist of µ-opioid receptors (MORs). At 7 days post-treatment, the model was assessed by analyzing stool scores and calculating the gastrointestinal (GI) transit ratio of rats. The distribution of P2Y1-expressing neurons in the colonic submucosal plexus was demonstrated by immunofluorescence (IF). Western blotting was performed to evaluate the expression changes of MOR, P2Y1 and ATP synthase subunit ß (ATPB) proteins in the colonic submucosa, while reverse transcription-quantitative PCR (RT-qPCR) analysis was performed to determine the relative mRNA expression of MOR and P2Y1. After 7 days, the feces of OIC rats exhibited an appearance of sausage-shaped pieces and both the stool weight and GI transit ratio of OIC rats were significantly decreased. IF revealed co-expression of P2Y1 and calbindin and MOR and ATPB in the nerve cells of the distal colonic submucosal plexus. Moreover, RT-qPCR analysis showed that the MOR mRNA levels were significantly increased in the distal colonic submucosa of OIC rats, while mRNA levels of P2Y1 were decreased. WB showed that in the distal colonic submucosa of OIC rats, MOR protein expression was increased, whereas that of P2Y1 was significantly decreased. GI transit ratio analysis suggested that the P2Y agonist ATP significantly relieved constipation symptoms in rats, while the P2Y inhibitor MRS2179 aggravated these symptoms. Finally, P2Y1 expression change was shown to be associated with the occurrence of OIC, while expression of MOR and P2Y1 was associated with OIC development in rats.

Simple Construction of Multistage Stable Silicon-Graphite Hybrid Granules for Lithium-Ion Batteries.

Because of its high specific capacity, the silicon-graphite composite (SGC) is regarded as a promising anode for new-generation lithium-ion batteries. However, the frequently employed two-section preparation process, including the modification of silicon seed and followed mixture with graphite, cannot ensure the uniform dispersion of silicon in the graphite matrix, resulting in a stress concentration of aggregated silicon domains and cracks in composite electrodes during cycling. Herein, inspired by powder engineering, the two independent sections are integrated to construct multistage stable silicon-graphite hybrid granules (SGHGs) through wet granulation and carbonization. This method assembles silicon nanoparticles (Si NPs) and graphite and improves compatibility between them, addressing the issue of severe stress concentration caused by uncombined residue of Si NPs. The optimal SGHG prepared with 20% pitch content exhibits a highly reversible specific capacity of 560.0 mAh g-1 at a current density of 200 mA g-1 and a considerable stability retention of 86.1% after 1000 cycles at 1 A g-1 . Moreover, as a practical application, the full cell delivers an outstanding capacity retention of 85.7% after 400 cycles at 2 C. The multistage stable structure constructed by simple wet granulation and carbonization provides theoretical guidance for the preparation of commercial SGC anodes.

Enhanced Organic Thin-Film Transistor Stability by Preventing MoO3 Diffusion with Metal/MoO3/Organic Multilayered Interface Source-Drain Contact.

The source-drain electrode with a MoO3 interfacial modification layer (IML) is considered the most promising method to solve electrical contact issues impeding organic thin-film transistors (OTFTs) from commercialization. However, this method raises many concerns because MoO3 might diffuse into organic materials, which causes device instability. In this work, we observed a significant device stability degradation by damaging on/off switching performance caused by MoO3 diffusion. To prevent the MoO3 diffusion, a source-drain electrode with a multilayered interface contact (MIC) consisting of a top-down stack of metal, MoO3 IML, and organic buffer layer (OBL) is proposed. In the MIC device, the MoO3 IML serves well for its intended functions of reducing contact resistance and suppressing minority carrier injection to the OTFT channel. The inclusion of OBL to the MIC helps block MoO3 diffusion and thereby leads to better device stability and an increased on/off ratio. Through combinations with several organic compounds as a buffer layer, the MoO3 diffusion related electrical behaviors of OTFTs are systematically studied. Key parameters related to MoO3 diffusion such as the Fick coefficient and bias-stress stability such as carrier trapping time are extracted from numerical device analysis. Finally, we summarize a general rule of material selection for making robust source-drain contact.

Erratum: Corection to "Multiple Sequence Long and Short Memory Network Model for Corner Gas Concentration Prediction on Coal Mine Workings".

[This corrects the article DOI: 10.1021/acsomega.2c05188.].

Synergistically interactive P-Co-N bonding states in cobalt phosphide-decorated covalent organic frameworks for enhanced photocatalytic hydrogen evolution.

Non-noble materials with high efficiency and stability are essential for renewable energy applications. Herein, cobalt phosphide nanoparticles-decorated covalent organic frameworks (CTF-CoP) are synthesized via an in situ self-assembly method combined with the calcination process. In such a configuration, an intimate interaction between CoP and CTF matrix is gained through the Co-N chemical bonds, which not only significantly enhance the recyclability of CoP nanoparticles but also significantly improve the charge separation efficiency. Besides, the synergistically interactive Pδ--Coδ+-Nδ- states induced by the polarization effect of N-anchoring sites benefit for the adsorption and dissociation of water molecules in CTF-CoP. Consequently, CTF-CoP exhibits a higher photocatalytic hydrogen evolution rate (261.7 µmol g-1 h-1) and better durability as compared with the physically fixed CTF/CoP composite (64.8 µmol g-1 h-1) and even the noble metal-based CTF-Pt (191.3 µmol g-1 h-1). This work provides an avenue to construct highly stable non-noble photocatalyst for energy conversion and also emphasizes the potential of CTFs in constructing efficient heterojunctions.

Multiple Sequence Long and Short Memory Network Model for Corner Gas Concentration Prediction on Coal Mine Workings.

To further improve the accuracy of recurrent neural network in predicting the gas concentration in the upper corner of the mine tunnel, this paper proposes a method to construct a gas concentration prediction model based on multiple sequence long and short memory network, considering the spatial correlation between the gas concentration in the return airway and upper corner. The reliability of the model construction is improved by using the white noise test and smoothness test to verify the interpretability of the data in this paper and constructing supervised learning type data for gas concentration prediction model training and testing by means of data set division and data windowing. Through experimental comparison, grid search, and time series decomposition, the model algorithm, training parameters, and experimental results were combined to make an in-depth analysis of the influence of each parameter on the model training and the prediction. A training model of the spatially fused gas concentration prediction model with a network layer of 1 and a number of neurons of 32 as the model structure, Adam as the optimization algorithm, and a learning rate of 0.001 and a batch size of 32 as the training parameters was finally determined. The gas concentration prediction model trained in this paper performed well in the test set with a mean square error (MSE) of 0.0013, and its superiority was verified by comparing it with other models to provide some experience and basis for subsequent studies on gas concentration prediction in the upper corner.

Dynamic Response and Service Life of Tunnel Bottom Structure Considering Hydro-Mechanical Coupling Effect under the Condition of Bedrock Softening.

Due to the long-term coupling effect of a train load and groundwater, the surrounding rock at the tunnel bottom will soften in a certain range and the mechanical parameters of the surrounding rock will decrease, causing the uneven distribution of the confining pressure at the tunnel bottom and affecting the base concrete structure service life. In this research, the method of combining field tests and numerical simulation is adopted, and the vertical displacement, vertical acceleration, and maximum and minimum principal stresses are used as evaluation indicators. The dynamic response law of the base structure with the softened surrounding rock of the heavy-duty train is analyzed, and the Miner linear cumulative damage theory is introduced to obtain the service life of the tunnel bottom structure under different softening conditions. The results show that with the decrease in the softening coefficient and the increase in the softening thickness of the bedrock, the displacement, acceleration, and principal stress response indexes of the structure increase by varying degrees, and the service life of the base structure decreases almost linearly. The maximum vertical displacement, acceleration, and tensile stress are located directly below the track, and the maximum compressive stress is located at the connection between the inverted arch and the side wall. According to the predicted value of the service life, the reliability of the base structure is divided into four levels: safety, warning, danger, and serious danger.

High Sulfur-doped hollow carbon sphere with multicavity for high-performance Potassium-ion hybrid capacitors.

S doping is an effective strategy to improve the potassium-ion storage performance of carbon-based materials. However, due to the large atomic radius of S and poor thermal stability, it is challenging to synthesize carbon materials with high sulfur content by solid-phase transformation. In this work, we designed a multi-cavity structure that can confine the molten S during heat treatment and make it fully react, then achieving high S doping (7.6 at. %). As we known, S doping can also effectively increase the active sites of carbon materials to obtain higher capacity. In addition, through different ex/in-situ characterizations and DFT calculations, we confirmed that the S atoms can effectively expand the interlayer spacing of carbon, which facilitates the intercalation/deintercalation reaction of K+, thereby significantly improving the rate performance. Therefore, benefiting from the effect of S-doping, the sample exhibits high reversible specific capacity (401.0 mAh g-1 at 0.1 A/g) and rate performance (167.2 mAh g-1 at 5 A/g). The as-assembled K+ hybrid capacitor delivers both high energy density and power density (138.5 W h kg-1 and 7692.5 W kg-1, respectively). This work provides a new approach to design S content carbon-based materials for high performance K+ storage.

Sodium alginate-derived porous carbon: Self-template carbonization mechanism and application in capacitive energy storage.

Sodium alginate (SA) is an environment-friendly and low-cost polysaccharide carbohydrate extracted from seaweed. As a carbon precursor, sodium alginate has the advantages of clear molecular structure, small molecular weight, and easy controls of the structure and composition of the product, but there have been few studies for the mechanism for SA carbonization. In this work, the carbon skeleton cross-linking mode, heteroatom doping and defect generation mechanism in the process of SA pyrolysis are clarified. Subsequently, based on the understanding of the carbonization mechanism of SA-derived carbon, we have prepared a stable SA-derived interconnected porous carbon by self-template method. The materials prepared by this method possess high oxygen content (17.6 at%) and high specific surface area (384.4 m2 g-1). Zn-ion hybrid capacitors (ZICs) device assembled with SA-derived porous carbon performs superior energy densities (based on cathode mass) of 78.35 and 35.56 Wh kg-1 at the power densities of 160 and 5120 W kg-1, respectively. This work deeply explained the carbonization mechanism of sodium alginate and evaluated the application prospects of SA-based carbon in ZICs comprehensively.