新型稠环电子受体的界面修饰对钙钛矿太阳能电池性能的影响

钙钛矿太阳能电池(perovskite solar cells, PSCs)因具有能量转换效率(power conversion efficiency, PCE)高、成本低、易于大面积制造等优点而被科学家们广泛关注.氧化物电子传输层的合理界面设计及修饰对提高器件的PCE和工作长期稳定性有着十分重要的意义.因此,本文采用一种含有烷基噻吩基侧链的稠环电子受体材料3,9-二(2-亚甲基-(3-(1,1-二氰甲烯基)-茚酮))-5,5,11,11-四(5-己基噻吩)-二噻吩并[2,3-d:2′,3′-d′]-s-引达省[1,2-b:5,6-b′]二噻吩(3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(5-hexylthienyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene, ITIC-Th)修饰TiO2电子传输层,制备高效稳定的平面结PSCs.研究结果显示,ITIC-Th的界面修饰改善了TiO2薄膜的形貌、接触角等性质,促进了钙钛矿晶粒的高质量生长,大幅度减少了器件表界面的电荷复合,明显提升了光生载流子的抽取率和输运效率,使经ITIC-Th界面修饰的PSC的PCE从未经界面修饰的15.43%显著提高到18.91%.与此同时,器件稳定性的研究结果显示,在室温和湿度为30%的条件下,经ITICTh界面修饰的PSC的PCE在放置约1000 h后依然保持原来的90%,明显高于未经界面修饰的PSC.研究结果对PSC光伏性能的提升具有重要的实际应用价值和学术意义.国家自然科学基金(61605164);;\n陕西省重点科技创新团队计划(2016KCT-28);;\n陕西省重点研发计划(2017ZDXM-GY-046);;\n福建省科技厅高校产学合作项目(2016H6023)资

1978～2008年中国湿地类型变化

分别基于美国陆地卫星(Landsat MSS/TM/ETM+)和中巴资源卫星(CBERS-02B)影像数据,以人工目视解译为主,完成了中国1978～2008年4期(基准年分别为1978,1990,2000和2008年)湿地遥感制图,并进行了大量的室内外验证.在此基础上,对我国湿地现状及近30年来湿地变化进行了初步分析,得到以下主要结论:(ⅰ)截止2008年,中国湿地面积约为324097km2,其中以内陆沼泽(35%)和湖泊湿地(26%)为主.(ⅱ)1978～2008年,中国湿地面积减少了约33%,而人工湿地增加了约122%.过去30年里湿地减少的速度大幅降低,由最初5523km2/a(1978～1990年)降为831km2/a(2000～2008年).(ⅲ)减少的自然湿地(包括滨海湿地和内陆湿地),其类型变化由湿地向非湿地转化的比例逐渐降低.初期(1978～1990年)几乎全部(98%)转换为非湿地;在1990～2000年间减少的自然湿地约有86%转化为非湿地,而在2000～2008年,这一比例下降为77%.(ⅳ)气候变化和农业活动是中国湿地变化的主要驱动因素,湿地变化在中国分为三大不同特征区域,即西部三省/自治区(西藏、新疆和青海)、北部两省/自治区(黑龙江和内蒙古)和其他省市区.其中西部区域尤其是青藏高原,湿地变化的驱动因子以气候增温为主;新疆湿地由于气候增温和农业活动共同作用造成变化不大.北部省/自治区的湿地变化则主要由农业活动引起;而其他省市区的湿地变化几乎完全受控于人类的农业经济活动

中国超大城市空气污染和人体健康 (APHH-Beijing) 中英联合研究计划 最终报告

Chinese versio

New zinc batteries for energy storage

 In general, metallic iron, aluminum and zinc are considered as the candidates for the anodes of aqueous batteries. Among them, the metallic zinc is the most promising one since it is more stable in aqueous solution than aluminum, and more electropositive than iron. In addition, zinc is naturally abundant, low in cost, high in energy density and environment friendly. Traditional Zinc-air cells (ZACs) suffer from cathode-related issues (e.g., CO2 contamination and electrode flooding) and have relatively low voltage. In addition, rechargeable zinc batteries, namely Zn-Ni batteries and Zn-Br2 flow batteries, encounter inherent challenges, e.g., the negative effect of zincate ions on the electrochemistry of the cathode (nickel hydroxide) in Zn-Ni batteries, the bromine crossover to zinc, and the possible bromine emission to environment in Zn-Br2 flow batteries. In this study, we develop two new types of zinc-air cells to improve the performance of traditional zinc-air cells, namely tri-electrolyte zinc-air cell (TE-ZAC) and tri-electrolyte microfluidic zinc-air cell (TEM-ZAC). The TE-ZAC, with a structure of zinc anode / aqueous 6 M KOH // cation exchange membrane (CEM) // aqueous saturated KCl // anion exchange membrane (AEM) // aqueous 6 M HCl / air-breathing cathode, delivers an open circuit voltage (Voc) of 2.0+ V and a maximum density of 130 mW cm-2. Compared to a traditional ZAC, the Voc and the maximum power density have been enhanced by ca. 33% and ca. 44%, respectively. The TEM-ZAC, where a microfluidic technology is utilized, exhibits a Voc as high as 2.18 V at an electrolyte flow rate of 0.075 ml min-1, which is, to the best of our knowledge, the highest voltage for ZACs. In addition, for both cells, the cathode-related issues encountered with traditional ZACs, are avoided since the alkaline for oxygen reduction reaction (ORR) is replaced with the acid. In this work, we have also developed three new concepts of rechargeable zinc aqueous cells, namely tri-electrolyte Zn-PbO2 (TE-Zn/PbO2) cell, dual-electrolyte Zn-LiCoO2 (DE-Zn/LiCoO2) cell, and hybrid Zn/active-carbon (H-Zn/AC) cell. The TE-Zn/PbO2 cell has low cost PbO2 as the cathode and delivers an average voltage as high as 2.1 V at a constant current of 25 mA (ca. 0.1C, where 1C means completing discharge / charge battery in 1 hour). The DE-Zn/LiCoO2 cell employs LiCoO2 as the cathode, delivers an average output voltage of 1.4 V at the discharge rate of 0.13C, and has a coulombic efficiency as high as 96%. Finally, the H-Zn/AC cell shows a 99.2% coulombic efficiency, and delivers an average output voltage of 0.8 V at a high discharge rate of 2.8C. The capacity retention is ca. 51% after 1700 cycles. Overall, although the cycle life of our cells is relatively low, the cycle performance can be greatly improved by either modifying the electrodes structure or adjusting the pH value of the catholyte. Most important of all, we demonstrate that our new cells work and have high potential for practical applications.published_or_final_versionMechanical EngineeringDoctoralDoctor of Philosoph