Study of Pb-based and Pb-free perovskite solar cells using Cu-doped Ni1-xO thin films as hole transport material

SCAPS solar cell simulation program was applied to model an inverted structure of perovskite solar cells using Cu-doped Ni_1-xO thin films as hole transport layer. The Cu-doped Ni_1-xO film were made by co-sputtering deposition under different deposition conditions. By increasing the amount of the Cu-dopant, the film crystallinity enhanced whereas the bandgap energy decreased. The transmittance of the thin films decreased significantly by increasing the sputtering power of copper. High quality, uniform, compact, and pin-hole free films with low surface roughness were achieved. The structural, chemical, surface morphology, optical, electrical, and electronic properties of the Cu doped Ni_1-xO films were used as input parameters in the simulation of Pb-based (MAPbI_3-xCl_x) and Pb-free (MAGeI₃) perovskite solar cells. Simulation results showed that the performance of both Pb-based and Pb-free perovskite solar cell devices significantly enhanced with Cu-doped Ni_1-xO film. The highest power conversion efficiency (PCE) for the Pb-free perovskite solar cell is 8.9% which is lower than the highest PCE of 17.5% for the Pb-based perovskite solar cell.     

增强纤维对全风积沙超高性能混凝土收缩性能的影响

早期自收缩是影响超高性能混凝土体积稳定性的重要因素,特别是由粒径较小的风积沙作为骨料的全风积沙超高性能混凝土。试验采用建筑中常用的三种增强纤维,探索纤维种类与掺量对全风积沙超高性能混凝土早期自收缩的抑制规律。通过试验发现,三种纤维对全风积沙超高性能混凝土早期自收缩抑制效果由大到小依次为:PVA纤维玄武岩纤维钢纤维,在一定范围内,纤维的掺量越高,对全风积沙超高性能混凝土早期自收缩抑制效果越好。这一结论为探索增强纤维对全风积沙超高性能混凝土自收缩性能影响的规律提供了参考。     

Low voltage operating organic light emitting transistors with efficient charge blocking layer

Charge injection/blocking layers play important roles in the performances of organic electronic devices. Their incorporation into organic light emitting transistors has been limitted, due to generally high operating voltages (above 60 V) of these devices. In this work, two hole blocking molecules are integrated into tris-(8-hydroxyquinoline) aluminum (Alq₃) based light emitting transistors under operating voltage as low as 5 V. The effects of hole blocking and electron injection are decoupled through the differences in the energy levels. Significantly improved optical performance is achieved with the molecule of suitable energy level for electron injection. Surprisingly, a decreased performance is observed in the case of another hole blocking molecule evidencing that charge injection overweighs charge blocking in this device architecture.     

Benzodithiophene-based small molecules with various termini as hole transporting materials in efficient planar perovskite solar cells

In this study we prepared four benzodithiophene (BDT)-based small organic molecules presenting bithiophene (TT), thiophene (FT), carbazole (CB), and triphenylamine (TPA) units, respectively, as termini, and used them as hole transporting materials for perovskite solar cells (PSCs). The high degrees of planarity of these BDT-based small molecules imparted them with high degrees of stacking and charge transport. These small molecules had suitable optical properties and energy level alignments for use in PSCs based on MAPbI₃, with compact-TiO₂ as the electron transporting layer and a BDT-based material as the hole transporting layer, in a n–i–p structure. Among our tested BDT-based materials, the PSC incorporating BDT-TT had the best performance, with an average power conversion efficiency of 13.63%.     

一次成井技术在北洺河铁矿的应用

采用7655型凿岩机进行浅孔凿岩施工切割天井一直是分段崩落采矿法常用方式，但是劳动强度大、效率低，且没有安全保障。为了降低施工切割天井的劳动强度、保证生产作业安全，根据北洺河铁矿地质特点和技术条件，采用国产8930型台车和SIMBA H1354型中孔台车取代7655型凿岩机进行中深孔凿岩和孔内分段爆破一次成井技术。经过大量现场试验验证，一次成井技术缩短工期4 d，提高了劳动效率，取得平均崩落高度8 m以上的良好爆破效果，按照北洺河铁矿每年施工15个切割天井计算，可节约11.98万元，为矿山降本增效提供了有效的技术支持。一次成井技术值得在全矿推广应用。     

Wrinkle free plaited knitted fabrics without pre-heat setting

Wrinkle free fabric at low cost is always a desirable aesthetic property. Different type of resins/finishes and pre-heat setting prior to processing are applied to avoid wrinkles in woven and hosiery, respectively. Current study is proposed to produce wrinkle free circular plaited knitted fabric by the elimination of a pre-boarding step. In this achievement, yarn covering parameters and compatibility of yarns with knitting machines are examined. Sock samples were analyzed for improved physical appearance (wrinkles) after various processes (pre-tumbling, dyeing, bleaching, and washing). Yarn specifications (sheath yarn fineness, sheath yarn texture i.e. shrink/un-shrink, covering air-knots) impact on socks physical appearance were also analyzed. The results clearly showed that by decreasing number of yarn covering air knots and sheath yarn fineness leads to prevention of wrinkle formation. The results also prove to be supportive for cost effectiveness by eliminating the pre-setting stage.     

1000WN挖泥泵高铬叶轮铸造过程质量控制

介绍了1000WN挖泥泵高铬叶轮的铸造过程。通过对叶轮铸造工艺设计与模拟分析,制定出了合理的铸造工艺;利用发热冒口进行高效能补缩,结合合理的退火、淬火工艺,严格生产过程质量控制,防止缩松、裂纹缺陷的产生,成功生产出了φ2500 mm,10.5 t的高铬叶轮。为大型挖泥泵高铬叶轮的国产化制造提供借鉴。     

Improving quality and machining efficiency of hole during AlN trepanning with nanosecond pulse laser

Aluminum nitride (AlN) is essential material to electronics industry. Compared to traditional machining methods, laser trepanning has become one of the most popular options for hole machining on AlN. Due to involvement of multiple parameters, such as scanning number, laser beam jump direction, scanning mode, and filling circle interval, the optimization of hole quality is complex. To tackle this problem, this paper systematically studied hole trepanning on AlN using nanosecond pulse laser in order to examine the relationship among trepanning parameters and hole dimensions, quality, and machining efficiency. Thereby, the optimized combination of parameters could be obtained to improve the quality and efficiency of hole machining. Moreover, possible effect mechanisms like effect of laser fluence on hole diameters, effects of jump directions and scanning modes on hole machining quality were discussed. Most importantly, it is the first time that the relationship among trepanning parameters, hole quality, and machining efficiency is presented.     

Transient shrinkage behavior of wustite-centered binary/ternary/quaternary/quinary-component oxide packed beds in a reducing atmosphere up to 1773 K

Wustite (FeO)-centered multicomponent oxides play an important role in the ironmaking process, and a complete understanding of their high temperature behaviors is of great importance for process optimization to achieve high efficiency and low emissions during industrial production. In this work, the transient shrinkages of FeO-centered multicomponent oxide packed beds are quantitatively determined in a reducing atmosphere up to 1773 K, and the effects of the interactions between the oxides on the shrinkage rate (SR) are qualitatively evaluated. The results show that although mixing CaO with FeO increases the SR to 0.42%/K below 1173 K, further mixing with SiO₂ or Al₂O₃ significantly limits this enhancement effect due to the formation of an olivine or spinel phase. However, in the subsequent stage, the SR increases to as high as 0.44%/K after CO is injected. The interaction between FeO and MgO leads to an SR of greater than 0.20%/K at lower temperatures, but it causes a decrease in the SR from 0.33%/K to 0.16%/K between 1173 K and 1273 K. Meanwhile, adding SiO₂ slows the reduction reaction, and the SR correspondingly decreases further to 0.04%/K. On the other hand, the interaction between CaO and Al₂O₃ takes precedence over the interaction between SiO₂ and MgO and dominates the shrinkage process in the quinary-component case, and the preferentially formed CaAl₂O₄ spinel phase hinders the formation of the Mg₂SiO₄ olivine phase.     

Channel length influenced contribution of hole and electron trapping effect to threshold voltage stability in organic field effect transistors

Effect of channel length on hysteresis and threshold voltage shift in copper phthalocyanine (CuPc) based organic field effect transistors was studied. Contrary to expectation, longer channel length devices exhibited minimum threshold voltage shift. Influence of channel length on the contribution of hole and electron trapping to threshold voltage stability was determined. Shortest channel length devices exhibited highest electron trapping effect while longest channel devices exhibited minimum hole as well as electron trapping. Lower hole trap effect for longer channel length devices was suggested to be due to reduced longitudinal field between source and drain electrodes while minimum electron trapping was attributed to suppression of drain current by increased hole trap centres.