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239 results on '"Yan, Shuwen"'

32. MXene‐Integrated Perylene Anode with Ultra‐Stable and Fast Ammonium‐Ion Storage for Aqueous Micro Batteries.

Author

Niu, Ke, Shi, Junjie, Zhang, Long, Yue, Yang, Mo, Shuyi, Li, Shaofei, Li, Wenbiao, Wen, Li, Hou, Yixin, Sun, Li, Yan, Shuwen, Long, Fei, and Gao, Yihua

Subjects
PERYLENE, ENERGY density, ANODES, ENERGY storage, SURFACE conductivity, CARRIER density
Abstract

The aqueous micro batteries (AMBs) are expected to be one of the most promising micro energy storage devices for its safe operation and cost‐effectiveness. However, the performance of the AMBs is not satisfactory, which is attributed to strong interaction between metal ions and the electrode materials. Here, the first AMBs are developed with NH4+ as charge carrier. More importantly, to solve the low conductivity and the dissolution during the NH4+ intercalation/extraction problem of perylene material represented by perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), the Ti3C2Tx MXene with high conductivity and polar surface terminals is introduced as a conductive skeleton (PTCDA/Ti3C2Tx MXene). Benefitting from this, the PTCDA/Ti3C2Tx MXene electrodes exhibit ultra‐high cycle life and rate capability (74.31% after 10 000 galvanostatic chargedischarge (GCD) cycles, and 91.67 mAh g−1 at 15.0 A g−1, i.e., capacity retention of 45.2% for a 30‐fold increase in current density). More significantly, the AMBs with NH4+ as charge carrier and PTCDA/Ti3C2Tx MXene anode provide excellent energy density and power density, cycle life, and flexibility. This work will provide strategy for the development of NH4+ storage materials and the design of AMBs. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Mechanistic and Kinetic Consideration of the Photochemically Generated Oxidative Organic Radicals in Dissolved Black Carbon Solutions under Simulated Solar Irradiation

Author

Jiang, Hongyu, Zhao, Mengzhe, Hong, Wenjie, Song, Weihua, and Yan, Shuwen

Abstract

The photochemically generated oxidative organic radicals (POORs) in dissolved black carbon (DBC) was investigated and compared with that in dissolved organic matter (DOM). POORs generated in DBC solutions exhibited higher one-electron reduction potential values (1.38–1.56 V) than those in DOM solutions (1.22–1.38 V). We found that the photogeneration of POORs from DBC is enhanced with dissolved oxygen (DO) increasing, while the inhibition of POORs is observed in reference to DOM solution. The behavior of the one-electron reducing species (DBC•–/DOM•–) was employed to explain this phenomenon. The experimental results revealed that the DO concentration had a greater effect on DBC•–than on DOM•–. Low DO levels led to a substantial increase in the steady-state concentration of DBC•–, which quenched the POORs via back-electron reactions. Moreover, the contribution of POORs to the degradation of 19 emerging organic contaminants (EOCs) in sunlight-exposed DBC and DOM solutions was estimated. The findings indicate that POORs play an important role in the photodegradation of EOCs previously known to react with triplets, especially in DBC solutions. Compared to DOM solutions, POOR exhibits a lower but considerable contribution to EOC attenuation. This study enhances the understanding of pollutant fate in aquatic environments by highlighting the role of DBC in photochemical pollutant degradation and providing insights into pollutant transformation mechanisms involving POORs.

Published
2024
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46. Tailoring of Photoluminescence Properties in All‐Vacuum Deposited Perovskite via Ruddlesden–Popper Faults.

Author

Wang, Liang, Li, Luying, Jia, Shuangfeng, Meng, Weiwei, Cheng, Yongfa, Liu, Zunyu, Li, Li, Yan, Shuwen, Gao, Yihua, Wang, Jianbo, and Tang, Jiang

Subjects
PEROVSKITE, PHOTOLUMINESCENCE, SCANNING transmission electron microscopy
Abstract

Ruddlesden–Popper (RP) faults are well known in oxide perovskites, and are also observed in promising metal halide perovskites. However, the effect of RP faults on optical properties of perovskite has not been systematically investigated. In this study, it is found that RP faults are common planar faults in all‐vacuum deposited CsPbBr3‐based perovskite polycrystal thin films, and the density of RP planar faults can be greatly increased by non‐stoichiometric composition (Cs‐rich) as well as reduced dimensionality (quasi‐2D) strategies. The photoluminescence (PL) measurement reveals monotonically increasing peak intensities with higher densities of RP planar faults from Cs‐rich, quasi‐2D to Cs‐rich & quasi‐2D samples. The corresponding atomic‐scale differential phase contrast maps indicate strongly confined charges within the RP planar fault network, which explains well the relationship between PL enhancement and the density of RP planar faults, and offers an alternative pathway for tailoring the optoelectronic properties of perovskite. [ABSTRACT FROM AUTHOR]

Published
2023
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