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Halide perovskites have distinguished themselves among the numerous optoelectronic materials due to their versatile processing technology and exceptional optical response. Unfortunately, their stability and toxicity from heavy metals severely hamper their development, in addition to the challenge of further improving photovoltaic performance. Hence, a lead-free perovskite-based heterojunction, C2N/CsGeI3, is investigated using a hybrid density functional, including electron structures, charge density differences, optical properties and more. The study reveals the presence of a built-in electric field directed from the CsGeI3 to the C2N layer. Moreover, based on the work function, it is confirmed that the electrons are transferred in a Z-scheme mechanism after the CsGeI3 contacts with the C2N layer. Under light irradiation, the construction of the C2N/CsGeI3 heterojunction significantly enhances optical absorption within the range of visible-light wavelengths. Additionally, the impact of interfacial strain on the C2N/CsGeI3 is explored and discussed. These findings not only suggest that the C2N/CsGeI3 heterojunction holds promise for photovoltaic applications but also provide a theoretical insight into lead-free perovskite-based functional materials. [ABSTRACT FROM AUTHOR]

Abstract: La-doped Ba0.6Sr0.4Co0.6Fe0.4O3−δ perovskites were synthesized and investigated as new cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). The structural characteristics, thermal expansion coefficient (TEC), electrical conductivity and electrochemical properties were characterized by X-ray diffraction (XRD), dilatometry, DC four-terminal method, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The TEC of (Ba0.6Sr0.4)0.9La0.1Co0.4Fe0.6O3−δ (BSLCF) was 14.9×10−6 K−1 at 30–800°C, lower than Ba0.6Sr0.4Co0.4Fe0.6O3−δ (BSCF) of 15.6×10−6 K−1. The electrical conductivity of BSCF was improved by La-doping, e.g. a value of 122Scm−1 for BSLCF vs. 52Scm−1 for BSCF at 500°C, respectively. In addition, La-doping enhanced the electrochemical activity for oxygen reduction reaction. The polarization resistance of BSLCF was 0.18Ωcm2 at 700°C, about a quarter lower than that of BSCF. The improved electrochemical performance of BSLCF should be ascribed to the higher conductivity as well as the improved oxygen adsorption/desorption and oxygen ions diffusion processes. [ABSTRACT FROM AUTHOR]

Abstract: The fabrication and electrochemical properties of graded La0.7Sr0.3CuO3−δ –Sm0.2Ce0.8O2−δ (LSCu–SDC) composite cathodes were investigated in this paper. The phase composition, microstructure and electrochemical properties of the electrodes were characterized using X-ray diffraction (XRD), electron microscopy, electrochemical impedance spectroscopy (EIS) and cathodic polarization examinations. The results showed that the triple-layer graded cathode had super electrochemical performance comparing with the monolayer cathode. The graded LSCu–SDC cathode showed a polarization resistance of 0.094 Ωcm2, a value much lower than the monolayer LSCu cathode of 0.234 Ωcm2 at 800 °C in air. The current density of the graded cathode was 0.341 A cm−2, more than double higher than monolayer LSCu of 0.146 A cm−2 at an overpotential of 30 mV. The improved electrochemical performance could be attributed to the improved physical and chemical compatibility of the cathode layers in graded compositions with SDC electrolyte as well as the enlargement of triple-phase boundary for oxygen reduction. [Copyright &y& Elsevier]

Abstract: The Nd1.7Sr0.3CuO4 (NSCu) material with perovsikite-related structure was synthesized and evaluated as a new cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion, electrical conductivity and electrochemical performance of NSCu have been investigated by X-ray diffraction, a dilatometer, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques. The polarization resistances of NSCu cathode on Sm-doped ceria (SDC) electrolyte in air were 0.07Ωcm2, 0.24Ωcm2 and 1.60Ωcm2 at 800°C, 700°C and 600°C, respectively. The results demonstrated that both impedance and CV methods are consistent with high exchange current density i 0 (390.7mA/cm2 and 76.1mA/cm2 at 800°C and 700°C.), making NSCu a promising cathode material for the IT-SOFCs based on doped ceria electrolytes. [Copyright &y& Elsevier]

Cobalt-free oxide Sr0.7Y0.3CuO2+δ (SYCu) with one-dimensional structure has been investigated as potential cathode material for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. The crystal structure, chemical compatibility, thermal expansion and electrochemical performance were examined by X-ray diffraction technique, electrochemical workstation and thermal dilatometer. One-dimensional structure Sr1−x Y x CuO2+δ and Sr2−x Y x CuO3+δ phases appeared as the main parts after calcination above 900 °C. The copper based oxide SYCu showed a thermal expansion coefficient (TEC) about 11.1 × 10−6/°C at 25–800 °C, exhibiting good physical compatibility with samarium doped cerium (SDC) electrolyte. High electro-catalytic performance was obtained for SYCu cathode in a symmetrical cell with a polarization resistance (R p ) of 0.029 Ω cm2 and an overpotential of 4.9 mV at 100 mA/cm2 at 800 °C, showing great promising use as cathode materials for IT-SOFCs. In addition, the polarization resistance of SYCu cathode remain constant after operation at 800 °C for 100 h, showing excellent long-term stability at operation temperature. [ABSTRACT FROM AUTHOR]

Abstract: The Ln1.7Sr0.3CuO4 (Ln=Nd, La), i.e., NSCu and LSCu materials with perovskite-related structure were synthesized and evaluated as new cathodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion, electrical conductivity and electrochemical performance of Ln1.7Sr0.3CuO4 cathodes have been investigated by X-ray diffraction, dilatometry, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques. The conductivity of NSCu and LSCu reached 106Scm−1 and 125Scm−1 at 800°C. NSCu cathode exhibited much lower area specific resistances (ASR) than LSCu, e.g., the ASR values for NSCu cathode on Sm-doped ceria (SDC) electrolyte in air were 0.07Ωcm2, 0.09Ωcm2 and 0.24Ωcm2 at 800°C, 750°C and 700°C, while the corresponding values for LSCu were 0.11Ωcm2, 0.21Ωcm2 and 0.44Ωcm2, respectively. To further optimize the electrochemical performance of the cathodes, a certain amount of Sm-doped ceria (SDC) electrolyte was introduced. The polarization resistance of NSCu–SDC30 and LSCu–SDC30 was 0.12Ωcm2 and 0.18Ωcm2 at 700°C in air, nearly half of pure NSCu and LSCu, respectively. [Copyright &y& Elsevier]

Halide perovskites have distinguished themselves among the numerous optoelectronic materials due to their versatile processing technology and exceptional optical response. Unfortunately, their stability and toxicity from heavy metals severely hamper their development, in addition to the challenge of further improving photovoltaic performance. Hence, a lead-free perovskite-based heterojunction, C 2 N/CsGeI 3 , is investigated using a hybrid density functional, including electron structures, charge density differences, optical properties and more. The study reveals the presence of a built-in electric field directed from the CsGeI 3 to the C 2 N layer. Moreover, based on the work function, it is confirmed that the electrons are transferred in a Z-scheme mechanism after the CsGeI 3 contacts with the C 2 N layer. Under light irradiation, the construction of the C 2 N/CsGeI 3 heterojunction significantly enhances optical absorption within the range of visible-light wavelengths. Additionally, the impact of interfacial strain on the C 2 N/CsGeI 3 is explored and discussed. These findings not only suggest that the C 2 N/CsGeI 3 heterojunction holds promise for photovoltaic applications but also provide a theoretical insight into lead-free perovskite-based functional materials.

Aim: This study aims to explore the association of cumulative exposure to cardiovascular health behaviors and factors with the onset and progression of arterial stiffness., Methods: In this study, 24,110 participants were examined from the Kailuan cohort, of which 11,527 had undergone at least two brachial-ankle pulse wave velocity (baPWV) measurements. The cumulative exposure to cardiovascular health behaviors and factors (cumCVH) was calculated as the sum of the cumCVH scores between two consecutive physical examinations, multiplied by the time interval between the two. A logistic regression model was constructed to evaluate the association of cumCVH with arterial stiffness. Generalized linear regression models were used to analyze how cumCVH affects baPWV progression. Moreover, a Cox proportional hazards regression model was used to analyze the effect of cumCVH on the risk of arterial stiffness., Results: In this study, participants were divided into four groups, according to quartiles of cumCVH exposure levels, namely, quartile 1 (Q1), quartile 2 (Q2), quartile 3 (Q3), and quartile 4 (Q4). Logistic regression analysis showed that compared with the Q1 group, the incidence of arterial stiffness in terms of cumCVH among Q2, Q3, and Q4 groups decreased by 16%, 30%, and 39%, respectively. The results of generalized linear regression showed that compared with the Q1 group, the incidence of arterial stiffness in the Q3 and Q4 groups increased by -25.54 and -29.83, respectively. The results of Cox proportional hazards regression showed that compared with the Q1 group, the incidence of arterial stiffness in cumCVH among Q2, Q3, and Q4 groups decreased by 11%, 19%, and 22%, respectively. Sensitivity analyses showed consistency with the main results., Conclusions: High cumCVH can delay the progression of arterial stiffness and reduce the risk of developing arterial stiffness.

CsPbX 3 (X = Cl, Br, and I) quantum dots (QDs) and Cu 2+ -doped CsPbCl 3 QDs with different Cu-to-Pb molar ratios were synthesized via a solvent-based thermal synthesis method. The photoluminescence (PL) properties of these Cu 2+ -doped CsPbCl 3 QDs were also investigated in this study. The results showed that with the increase in the Cl - concentration the surface defects of CsPb(Cl/Br) 3 QDs increased, which resulted in an increase in the non-radiative recombination of excitons and weakened the PL intensity. Moreover, Cu 2+ -doped CsPbCl 3 QDs maintained the cubic crystal structure of the initial phases. Owing to the doping of Cu 2+ ions, the surface defects of CsPbCl 3 QDs were effectively eliminated, which facilitated the excitonic recombination via a radiative pathway. The PL quantum yields (PLQYs) of Cu 2+ -doped CsPbCl 3 QDs were increased to 51%, showing great photostability. From the results, it is believed that Cu:CsPbCl 3 QDs can be widely used in optoelectronic devices., Competing Interests: The authors have declared that no conflicting interests exist., (This journal is © The Royal Society of Chemistry.)

Corynebacterium glutamicum is one of the most important traditional industrial microorganisms and receiving more and more attention towards a novel cellular factory due to the recently rapid development in genomics and genetic operation toolboxes for Corynebacterium. However, compared to other model organisms such as Escherichia coli, there were few studies on its metabolic regulation, especially a genome-scale integrated cellular network model currently missing for Corynebacterium, which hindered the systematic study of Corynebacterium glutamicum and large-scale rational design and optimization for strains. Here, by gathering relevant information from a number of public databases, we successfully constructed an integrated cellular network, which was composed of 1384 reactions, 1276 metabolites, 88 transcriptional factors and 999 pairs of transcriptional regulatory relationships. The transcriptional regulatory sub-network could be arranged into five layers and the metabolic sub-network presented a clear bow-tie structure. We proposed a new method to extract complex metabolic and regulatory sub-network for product-orientated study taking lysine biosynthesis as an example. The metabolic and regulatory sub-network extracted by our method was more close to the real functional network than the simplex biochemical pathways. The results would be greatly helpful for understanding the high-yielding biomechanism for amino acids and the re-design of the industrial strains.