Search

Long-term stability of organic solar cells is critical to promote practical applications. Here, the authors utilize iridium/iridium oxide nanoparticles as the electron-transporting material and realize enhanced device stabilities under thermal aging with T70 of over 10000 h.

MS2 (M = Mo; W), with natural atomic thickness, are typical two-dimensional (2D) semiconductor materials, which have excellent electronic/optoelectronic properties and mechanical flexible properties. With the development of semiconductor device miniaturization, much attention has been brought to MS2, especially in large-scale integrated circuits, ultra-sensitive photodetectors, and flexible electronic devices. Here, we present the recent research progress on the controllable synthesis of high-quality, wafer-scale, uniform monolayer and multilayer MS2 films by chemical vapor deposition methods, focusing on the most concerning grain orientation control and defect modulation in whole wafer, besides the pursuit of more larger wafer size in MS2 films’ preparation. We also discuss some critical issues in the process of MS2 films growth and give a brief outlook in the controllable preparation of high-quality MS2 films for device application later on.

The contamination of surface water by pharmaceuticals and personal care products (PPCPs) has attracted widespread attention, but data regarding their impacts on groundwater (GW) are sparse. In river–GW interaction areas, rivers are likely an important source of PPCPs in aquifers, especially rivers impacted by sewage treatment plant effluent. Understanding the characterization, transport, and risk is valuable for the effective protection of vital aquatic ecosystem services, environmental health, and drinking water supplies. To attain this objective, statistics with spatial analysis and ecological risk were used to assess the effects of artificial recharge (AR) engineering on 16 PPCPs in aquifers in North China. The results indicated that 15 PPCPs were detected in unconfined and confined aquifers, with a few PPCPs being detected up to 1,000 ng/L. The most frequently detected PPCPs were sulfisoxazole, sulfachloropyridazine, sulfamerazine, sulfamethazine, sulfamethoxazole, and ibuprofen. In addition, the spatial and seasonal variations in most PPCPs were significant. Furthermore, the maximum concentrations were compared to the predicted no-effect concentrations to evaluate the ecological risk, and four PPCPs were found to be of medium or high ecological risk. This study highlights that AR engineering has a significant ecological effect on GW.

Transportation of carbonate and sulfate ions in concrete under the drying-wetting cycle environment is similar to the ingression and elimination of medicine in human body. Given this similarity, such a process is described dynamically using the classic compartment model in pharmacokinetics. The compartment model was applied to predict the content of carbonate and sulfate ions in different regions of concrete. Factors such as water-cement ratio, salt category, carbonate-ion and sulfate-ion attack depth, and drying-wetting cycle were synthetically considered in the compartment model. In conjunction with the prediction value of the compartment model, the experiment data uniformly distributed two sides of the model curve, and the difference is within the accepted range, thus verifying the reliability of the model prediction consequence. The compartment model in this article provides references for predicting the drying-wetting varied cycles and ions attack depth of concrete under carbonate and sulfate ions attack.

Given the excellent crack resistance performance of steel fiber-reinforced self-stressing concrete (SFRSSC), the bending performance of some composite beams with SFRSSC laminated layers was studied. The experiment conducted in this study comprised a single-span composite beam test (including 3 test beams) and a two-span continuous composite beam test (including 2 test beams). All the test beams were T-shaped. The cracking load, yielding load, and ultimate load of all the test beams were recorded and comparatively analyzed. Experimental results showed that the cracking load of the test beam with an SFRSSC laminated layer is significantly increased. Mechanical analysis and numerical simulation of the test beams were conducted, and the obtained results agreed well with the experimental results. The composite beams under different working conditions were also numerically simulated. Through the simulation, reasonable ranges of precompressive stress and length of the SFRSSC laminated layer at intermediate support of continuous composite beam were obtained.

MS2 (M = Mo; W), with natural atomic thickness, are typical two-dimensional (2D) semiconductor materials, which have excellent electronic/optoelectronic properties and mechanical flexible properties. With the development of semiconductor device miniaturization, much attention has been brought to MS2, especially in large-scale integrated circuits, ultra-sensitive photodetectors, and flexible electronic devices. Here, we present the recent research progress on the controllable synthesis of high-quality, wafer-scale, uniform monolayer and multilayer MS2 films by chemical vapor deposition methods, focusing on the most concerning grain orientation control and defect modulation in whole wafer, besides the pursuit of more larger wafer size in MS2 films’ preparation. We also discuss some critical issues in the process of MS2 films growth and give a brief outlook in the controllable preparation of high-quality MS2 films for device application later on. [ABSTRACT FROM AUTHOR]

Although the photovoltaic performance of perovskite solar cells (PSCs) has reached commercial standards, the processing environment of a purely inert gas atmosphere significantly increases the cost of installing manufacturing facilities in actual manufacturing plants and hinders their commercial mass production. The thermal annealing condition of quasi-2D perovskite films can significantly affect the selfassembly behavior of bulky organic cations, which modulates the phase distribution of 2D species with different n values. Herein, the properties of quasi-2D perovskite annealing in a N2 versus an environment representative of industrial conditions, i.e., open-air with 30% humidity are compared. It is found that the crystallization process of perovskites is regulated by air annealing, leading to high-quality 2D perovskite films with reduced trap density, well-aligned phase distribution, and released residual strain. The resulting devices prepared by air annealing achieve a power conversion efficiency of 18% with high reproducibility and suppressed voltage loss. The enhanced thermal stability of the air-annealed films is proved by in situ grazing incidence wide-angle X-ray scattering. The combination of air annealing and simple planar structures would facilitate the mass production of PSCs. [ABSTRACT FROM AUTHOR]

Aiming at the serious noise of bridge vibration signals in complex environment, this paper proposed an adaptive filtering and denoising optimization method for bridge structural health monitoring. The method took CEEMDAN algorithm as the core, during the step-by-step decomposition of original signals, white noise with opposite signs was added in each stage, meanwhile multi-scale permutation entropy (MPE) was introduced to analyze the mean entropy of each intrinsic mode function (IMF) at different scales, and components with serious noise were eliminated to complete the first filtering; then, in order to optimize the remaining IMFs for signal reconstruction and ensuring the smoothness and similarity of filtering, an optimized reconstruction model was established to complete the second filtering. Compared with the CEEMDAN method, the proposed method could solve the problems of mode mixing and endpoint effect with good completeness, orthogonality, and signal-to-noise ratio. At last, the advantages and application value of the proposed method were verified again by the vibration signal analysis of a real long-span bridge structure. [ABSTRACT FROM AUTHOR]

Although the improvement of power conversion efficiency (PCE) in organic photovoltaic cells (OSC) is due to the development of novel donors and non-fullerene acceptors, state-of-the-art devices commonly utilize charge transporting/extraction interlayers. Here we demonstrate a universal approach based on a series of tetraalkyl ammonium bromide (TXABr) Lewis bases as ndopants for mediating electron extracting properties in a range of OSCs with non-fullerene or PCBM acceptors. Under optimal conditions, the TXABr-doped devices without electron transporting layers (ETLs) exhibit PCEs comparable to those of the ones based on a conventional device structure containing ETLs. We found that the doping efficiency of acceptors is intimately correlated with the chain length (Lchain) of dopants. In OSCs based on acceptors of ITIC derivatives (IT-4F, ITIC, ITM, and ITCC), similar Lchain-dependent doping efficiency and PCE modification are found, while for OSCs with acceptors bearing different structures in conjugated backbones or side chains, the selection rule of dopants to achieve the best performance enhancement is different. These correlations are explained by the mutual effects of electrostatic interaction in the dopants and steric hindrance between the dopants and acceptors, the latter of which is affected by the compatibility of side chains in the host and dopant. With TXABr doping, (quasi-)ohmic contacts for electrons are realized in these ETL-free devices, leading to expediting the charge sweepout with mitigated interfacial charge recombination. This work offers a promising pathway to realize high efficiency non-fullerene OSCs with simplified device architecture. [ABSTRACT FROM AUTHOR]