Efficient organic solar cells enabled by simple non-fused electron donors with low synthetic complexity

Abstract Fused‐ring electron donors boost the efficiency of organic solar cells (OSCs), but they suffer from high cost and low yield for their large synthetic complexity (SC > 30%). Herein, the authors develop a series of simple non‐fused‐ring electron donors, PF1 and PF2, which alternately consist of furan‐3‐carboxylate and 2,2′‐bithiophene. Note that PF1 and PF2 present very small SC of 9.7% for their inexpensive raw materials, facile synthesis, and high synthetic yield. Compared to their all‐thiophene‐backbone counterpart PT‐E, two new polymers feature larger conjugated plane, resulting in higher hole mobility for them, especially a value up to ≈10 −4 cm 2 V −1 ·s for PF2 with longer alkyl side chain. Meanwhile, PF1 and PF2 exhibit larger dielectric constant and deeper electronic energy level versus PT‐E. Benefiting from the better physicochemical properties, the efficiencies of PF1‐ and PF2‐based devices are improved by ≈16.7% and ≈71.3% relative to that PT‐E‐based devices, respectively. Furthermore, the optimized PF2‐based devices with introducing PC 71 BM as the third component deliver a higher efficiency of 12.40%. The work not only indicates that furan‐3‐carboxylate is a simple yet efficient building block for constructing non‐fused‐ring polymers but also provides a promising electron donor PF2 for the low‐cost production of OSCs.A simple structure non‐fused‐ring electron donor PF2 alternately consisting of furan‐3‐carboxylate and 2,2′‐bithiophene presents very small synthetic complexity of 9.7% as well as low material cost of ≈19.0 $ g −1 . More importantly, PF2 delivers a high efficiency of 12.4% coupled with strong operational stability. imag

Long term detection of water depth changes of coastal wetlands in the Yellow River Delta based on distributed scatterer interferometry

Coastal wetland ecosystems are among the most productive yet highly threatened systems in the world, and population growth and increasing economic development have resulted to extremely rapid degradation and loss of coastal wetlands. Spaceborne differential Interferometry SAR has proven a remarkable potential in wetland applications, including water level monitoring in high spatial resolution. However, due to the absence of ground observations for calibration and validation, long term monitoring of water depth, which is essential to evaluate ecosystem health of wetlands, is difficult to be estimated from spaceborne InSAR data. We present a new differential synthetic aperture radar method for temporal evolution of water depth in wetlands. The presented technique is based on distributed scatter interferogram technique in order to provide a spatially dense hydrological observation for coastal wetlands, which are characterized by high temporal decorrelation. This method adapts a strategy by forming optimum interferogram network to get a balance between maximum interferometric information preservation and computational cost reduction, and implements spatial adaptive filtering to reduce noise and enhance fringe visibility on distributed scatterers. Refined InSAR observation is tied to absolute reference frame to generate long term high resolution water level time-series using stage data. We transform water level time-series to long term observation of water depth with assistance of a dense measurement network of water depth. We present water depth time-series obtained using the data acquired from 2007 to 2010 by the ALOS satellite, which supplied significant information to evaluate ecological performance of wetland restoration in the Yellow River Delta

Influence of helium ion irradiation on the morphology and microstructure of CN-G01 beryllium

Beryllium is considered as a candidate of ITER first-wall (FW) armor and neutron multiplier in fusion reactors. To assess the irradiation resistance of CN-G01 beryllium, which has been accepted as an alternative ITER-grade beryllium in China, 180 keV helium ions with fluences of 1.0 × 10 ^17 ions cm ^−2 , 5.0 × 10 ^17 ions cm ^−2 and 1.0 × 10 ^18 ions cm ^−2 were implanted at room temperature. The theoretical simulation of energy loss, damage distribution and helium concentration were proceeded by SRIM. In this paper, we report the experimental exploration of ion fluence effect on surface morphology and microstructure of irradiated samples. Field Emission Scanning Electron Microscope (FESEM) analysis depicted the formation and growth of helium bubbles at different irradiation ion fluences. No obvious exfoliation or cavities was observed on the surface at all ion fluences, suggesting a reliable radiation resistance of CN-G01 beryllium. Atomic force microscopy (AFM) morphology showed that the maximum height of bubbles was 47.8 nm. Surface roughness values increased slightly due to the formation of defects and bubbles on the irradiated beryllium surface. Nevertheless, the structural analysis demonstrated by grazing incidence x-ray diffraction (GIXRD), indicated an obvious preferred orientation on (101) peak at various ion fluences. Annihilation of defects caused by a small rise of the localized temperature could explain the increasing intensity of diffraction peak (101)

Mechanical response and data-driven fatigue model of interlayer soils in track-bed considering multi-factor coupling effect

International audienc

Evolution of land subsidence and comparative study on multi-source monitoring methods in New Airlines City of Beijing

To reveal the evolution law of land subsidence in the New Airlines City of Beijing, the characteristics of land subsidence in this area are analyzed by combining bedrock standard-layered standard and leveling survey, and the comparative study and evaluation are carried out with different monitoring methods. The results show that: ①In recent ten years, the amount and proportion of subsidence in the shallow stratum of the Xinhangcheng area are smaller and smaller, the proportion of subsidence decreased from 67.62% in 2009 to 19.69% in 2019, while the amount and proportion of subsidence in the middle stratum and deep stratum are increasing with time, the proportion of middle stratum subsidence increased from 21.39% in 2009 to 35.83% in 2019, and the proportion of deep stratum subsidence increased from 10.99% in 2009 to 44.48% in 2019;the water level of the shallow aquifer changes periodically, while that of the middle stratum and deep aquifer decreases continuously, the strata continue to compress in the periodic change of water level. ②According to the results of the level survey and groundwater dynamic monitoring over the years, the accumulated settlement from north to south in the research area gradually decreases. After fitting the data of land subsidence and groundwater level, it is found that there is a certain correlation between them, the correlation increases with the increase of water level drop, and there is a positive correlation between them. ③The error value of the static leveling system of bedrock standard layered standard and artificial leveling system after mutual correction of the same monitoring point and different depth data is very close, which conforms to the normal distribution law, and the correlation coefficient of monitoring data of different depth is 0.993 6; comparing the two methods has advantages and disadvantages, it is suggested to obtain the settlement information and data in many aspects based on the actual situation, to meet the regional requirements different demands of the monitoring and prevention of the grade land subsidence

Microstructure Change, Nano-Hardness and Surface Modification of CN-G01 Beryllium Induced by Helium Ions

The helium effects in Chinese developed CN-G01 beryllium are important issues for its use in nuclear energy systems. In this work, the CN-G01 beryllium samples were irradiated with helium ions to fluences of 5.0 × 1016 ions/cm2 to 1.0 × 1018 ions/cm2 at room temperature and investigated by techniques of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nano-indentation. It was found that the irradiation induced hardening of beryllium and the nano-hardness of the samples increased with increasing fluence of 5.0 × 1016 ions/cm2 to 1.0 × 1017 ions/cm2. When the fluence reached 5.0 × 1017 ions/cm2 and 1.0 × 1018 ions/cm2, helium irradiation induced serious surface blistering and its burst. TEM observation found that helium bubbles in the damage peak region became visible when the fluence reached 1.0 × 1017 ions/cm2. With increasing fluence, helium bubbles became larger and connected into large cracks. The underlying physical mechanisms are discussed based on the helium behavior at low temperatures and the contributions of helium induced defects. This work will provide some new understanding on the irradiation resistance of CN-G01 beryllium and the helium effects in beryllium at low temperatures

Irradiation resistance properties studies on helium ions irradiated MAX phase Ti3AlC2

The study presents an investigation of irradiation resistance properties of Ti3AlC2 under 500 keV He ions irradiation with the doses ranging from 5.0 x 10(16) to 1.0 x 10(15) ions cm(-2) at certain temperatures, like room temperature (RT), 300 and 500 degrees C X-ray diffraction (XRD) and Transmission electron microscopy (TEM) are used to study the evolution of structural damage and the behavior of deposited He ions respectively. XRD analysis reveals that for the highest dose irradiation (similar to 52 dpa at peak), no amorphization occurs. And the structural recovery of Ti3AlC2 is more significant accompanied with the gradual disappearance of the irradiation-induced TiC phase as the temperature rises from RT to 300 and to 500 degrees C with the same dose irradiation. TEM observations show that He bubbles appear in the shapes of sphere, string and platelet but no big bubbles are formed for all irradiations. Moreover, no large cracks form in the sample implanted with the highest helium concentration of similar to 6.4 x 10(5) appm. (C) 2014 Elsevier B.V. All rights reserved

Additional file 2: Figure S2. of Label-Free 3D Ag Nanoflower-Based Electrochemical Immunosensor for the Detection of Escherichia coli O157:H7 Pathogens

SEM images of Ag@BSA microspheres prepared without BSA addition. (TIF 398 kb