119 research outputs found
Small molecular hole-transporting materials for efficient inverted perovskite solar cells
No full textHybrid Organic-Inorganic perovskite solar cells (PVSCs) are a new type of thin-film solar cells based on inorganic-organic hybrid metal halide active materials. Perovskites show many distinctive advantages, such as strong light absorption, small exciton binding energy, adjustable optical band gap, high charge carrier mobility, long charge carrier lifetime, and solution processability. Therefore, PVSCs, with perovskite as the light absorption layer, exhibit excellent photovoltaics performance. The inverted PVSCs can form films at low temperatures and lower the production cost, providing the possibility for the commercial development of flexible devices. High-mobility charge transport layers can improve exciton separation and reduce carrier recombination, which is essential to obtain highly efficient PVSCs. Small molecular HTMs (SM-HTMs) have a well-defined molecular structure and molecular weight, and there is negligible batch-to-batch variation, so the device performance has better reproducibility. In this thesis, the design of SM-HTM, as well as their high-efficiency devices, are discussed by studying four high-efficiency PVSC systems. Firstly, three isomeric HTMs based on distinct dithienothiophene π-bridge were synthesized, suggesting that a small change of the regioisomeric π-bridge structure of D-π-D typed molecules can greatly alter their photophysical properties. A power conversion efficiency (PCE) of 19.23% was achieved with 3T-3. Secondly, a green-solvent-processable hole-transport material M1 enabled by a traditional bidentate ligand 1,10-phenanthroline was synthesized and showed effective perovskite surface passivation, achieving a high PCE of 20.14%. Thirdly, a D-A-D type hole-transport material TPA-FO features an inexpensive aromatic ketone, 9-fluorenone as the core, and enables inverted perovskite solar cells with an efficiency of 20.24%. Our results suggest that constructing SM-HTMs with versatile conjugated planar cores like polythiophenes, 1,10-phenanthroline, and aromatic ketones shows the potential to develop the low-cost, ecofriendly-processable HTMs toward highly efficient PVSCs and give some insight into the structure-property relationship of SM-HTMs.</p
CpG DNA Induces IgG Class Switch DNA Recombination by Activating Human B Cells through an Innate Pathway That Requires TLR9 and Cooperates with IL-10
No full textComparative Study in Functional Morphology of Antennary Gland of Pacific White Shrimp, Litopenaeus Vannamei, Reared under Various Salinity Condition
No full textPlasmacytoid dendritic cells and the regulation of immunoglobulin heavy chain class switching
No full textDianping.com: Simplifying Reservation Service Products
No full text2012年5月末的一天，大众点评创始人、CEO张涛与高级产品经理王旭刚及其团队刚刚结束会议，王旭刚情绪不高，团队负责的预约预订业务产品开发提案被张涛否决了。张涛认为这一提案脱离了商户的现有使用习惯，而MVP产品也设计得过于复杂，没有聚焦在核心消费者最为迫切的需求上。王旭刚有些迷惑，餐饮市场商户管理水平参差不齐，预订流程还停留在纸加笔的阶段，消费者的用户习惯却已经被移动互联网大大改变，要考虑到双方习惯，又要简洁高效，王旭刚遇到了设计产品的难题。One day at the end of May 2012, Zhang Tao, the founder and CEO of Dianping.com, and Wang Xugang, the senior product manager, and his team just finished a meeting. Wang Xugang was feeling down because the proposed reservation service product in the charge of his team had been rejected by Zhang Tao. Zhang thought that the proposal was too far removed from users' habits and that the MVP product design was too complex to address their core consumers' most urgent needs. Wang was baffled: The level of management in the catering industry varied widely and the reservation process still depended on paper and pen, yet consumer habits had been greatly changed by mobile Internet. He faced the challenge of simultaneously considering the habits of both sides while keeping the product simple and efficient
Enhancing Nitrate Removal from Freshwater Pond by Regulating Carbon/Nitrogen Ratio
No full textNitrogen accumulation is a serious environmental problem in freshwater ponds, which can lead to massive death of fish and shrimps as well as the eutrophication. The removal of nitrate by regulating the carbon to nitrogen (C/N) ratio and the underlying mechanisms were investigated. The nitrate removal system comprised 530-mL medium containing 5 mg/L NO3−-N and 0–66.6 mg/L COD (i.e., C/N ratio of 0–13.3) and 20 g ponds sediments. When the C/N ratio was higher than 8, the nitrate removal efficiency nearly reached 100% during the incubation period and the accumulation of nitrite was negligible. When the C/N ratio was below 8, the nitrate removal efficiency was lower and significant nitrite accumulation occurred. The nitrate removal rate increased with the C/N ratio increased, which was ascribed to the increase in the absolute abundance of denitrifiers (nirS, nirK, and nosZ). Although both nirS-type and nirK-type denitrifiers were found in the sediments of freshwater pond, nirS-type denitrifiers were predominant. Dechloromonas was the major nirS-type denitrifier for nitrate removal in nirS-type with the C/N ratios above 5.33, while the majority of the nirK-type denitrifiers were unclassified. Thus, this study implied that the appropriate C/N ratio played an important role on the removal of excess nitrate from freshwater ponds
Generalized Learning of Neural Network Based Semantic Similarity Models and Its Application in Movie Search
No full textDesign of high accuracy high conversion ratio single-stage switching power converter for modern FPGAs at 10MHz
No full text- …
