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185 results on '"Miao Xiaofei"'

7. Rational Design of Hierarchical Structure Electrodes to Suppress Shuttle Diffusion in Redox-Enhanced Supercapacitors

Author

Miao, Xiaofei, Chen, Jingye, Zhong, Chenyang, Tong, Jing, Yang, Huayan, Yang, Xifeng, Qiao, Xuebin, Song, Zhongxin, and Zhang, Lei

Abstract

In carbon-based supercapacitors, redox couples can effectively improve the energy density of supercapacitors; however, most redox couples still suffer from serious shuttle diffusion. Currently, there is no universal strategy to effectively constrain their shuttle diffusion. Therefore, developing a simple, effective, and universal method to suppress shuttle diffusion remains a great challenge. Herein, we designed and prepared a hierarchical structure electrode composed of three functional layers (inner conductive layer, intermediate storage layer, and outer confinement layer) for redox-enhanced supercapacitors. The hierarchical electrode can be fabricated on a large scale in three simple steps based on commercial carbon felt. The rationally designed three functional layers endow the hierarchical structure electrode with excellent conductivity, adsorption capacity, and confinement ability. Long-term charge–discharge cycle results prove that the hierarchical structure electrode exhibits an outstanding restriction effectiveness on three redox media with different molecular sizes (anthraquinone (AQ), naphthoquinone (NQ), and p-benzoquinone (PQ)). Specifically, for AQ, NQ, and PQ, the hierarchical structure electrodes showed CV peak current attenuation rates of only 5.64%, 3.54%, and 10.34% after 5,000 cycles of charge–discharge, while common electrodes exhibited attenuation rates of 10.44%, 15.02%, and 20.20%, respectively. Moreover, the soft-pack supercapacitors composed of hierarchical electrodes still had a capacitance retention of 86.6% after 5,000 cycles of charge–discharge. All the results demonstrate that the structure design is reasonable and the hierarchical structure electrode has a great potential to be the universal electrode for suppressing the shuttle diffusion of redox media in supercapacitors and other energy storage devices.

Published
2024
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17. Tailoring the Dynamics of Excited‐State Charge Transfer through Conformational Engineering to Improve Second Near‐Infrared Fluorescence for High‐Resolution Osteosarcoma Imaging

Author

Li, Minghui, primary, Chen, Guojing, additional, Jia, Mingxuan, additional, Zhang, Jie, additional, Miao, Xiaofei, additional, Yao, Weiyun, additional, Fan, Yibo, additional, Lu, Yajie, additional, Xiao, Xin, additional, Fan, Quli, additional, Hu, Wenbo, additional, and Li, Jing, additional

Published
2024
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19. A Hot Exciton Luminogen Constructed by an o‐Carborane Scaffold.

Author

Yu, Xiao, Xu, Jingkai, Wang, Mengmeng, Miao, Xiaofei, Fan, Quli, Tu, Deshuang, Wang, Zhaojin, Duan, Chunbo, Lu, Changsheng, Xu, Hui, and Yan, Hong

Subjects
CHARGE transfer, ELECTRON donors, EXCITED states, ABSORPTION spectra, SPACE charge, PHOTOLUMINESCENCE
Abstract

Emitters with the combination of an electron donor (D) and an acceptor (A) have been widely studied and usually exhibited interesting photophysical properties. Hot exciton materials involving an ordinary D‐A structure typically undergo a hybridized local charge transfer (HLCT) process. However, the hot exciton molecules containing more D/A fragments are much less explored. In this study, a new hot exciton material based on an inorganic boron cluster is designed and synthesized, which possesses a V‐type D–A–A′–D′ molecular architecture. The emitter shows an impressive photoluminescence quantum yield (PLQY) of up to 90% and demonstrates multiple emissions, excitation‐wavelength‐, solvent‐, and temperature‐dependent emissions. These characteristics are attributed to the coexistence of HLCT and the through‐space charge transfer process (TSTC) triggered by an o‐carborane scaffold in the excited state. Besides, the interchangeable HLCT/TSCT/hRISC processes are demonstrated by temperature‐dependent spectra and femtosecond time‐resolved transient absorption spectra. These findings confirm a novel hot exciton mechanism, simultaneously induced by HLCT and TSCT. This is also the first example of a carborane‐based hot exciton molecule. The current study not only reports a new molecular architecture for a hot exciton material but also gives rise to a new insight into the hot exciton mechanism. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Near Infrared-II Excited Triplet Fusion Upconversion with Anti-Stokes Shift Approaching the Theoretical Limit

Author

Jiang, Lin-Han, Miao, Xiaofei, Zhang, Ming-Yu, Li, Jia-Yao, Zeng, Le, Hu, Wenbo, Huang, Ling, and Pang, Dai-Wen

Abstract

The anti-Stokes shift represents the capacity of photon upconversion to convert low-energy photons to high-energy photons. Although triplet exciton-mediated photon upconversion presents outstanding performance in solar energy harvesting, photoredox catalysis, stereoscopic 3D printing, and disease therapeutics, the interfacial multistep triplet exciton transfer leads to exciton energy loss to suppress the anti-Stokes shift. Here, we report near infrared-II (NIR-II) excitable triplet exciton-mediated photon upconversion using a hybrid photosensitizer consisting of lead sulfide quantum dots (PbS QDs) and new surface ligands of thiophene-substituted diketopyrrolopyrrole (Th-DPP). Under 1064 nm excitation, this photon upconversion revealed a record-corrected upconversion efficiency of 0.37% (normalized to 100%), with the anti-Stokes shift (1.07 eV) approaching the theoretical limit (1.17 eV). The observation of this unexpected result is due to our discovery of the presence of a weak interaction between the sulfur atom on Th-DPP and Pb2+on the PbS QDs surface, facilitating electronic coupling between PbS QDs and Th-DPP, such that the realization of triplet exciton transfer efficiency is close to 100% even when the energy gap is as small as 0.04 eV. With this premise, this photon upconversion as a photocatalyst enables the production of standing organic gel via photopolymerization under 1064 nm illumination, displaying NIR-II photon-driven photoredox catalysis. This research not only establishes the foundation for enhancing the performance of NIR-II excitable photonic upconversion but also promotes its development in photonics and photoredox catalysis.

Published
2024
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25. Acceptor Engineering Produces Ultrafast Nonradiative Decay in NIR-II Aza-BODIPY Nanoparticles for Efficient Osteosarcoma Photothermal Therapy via Concurrent Apoptosis and Pyroptosis

Author

Shi, Zhenxiong, primary, Bai, Hua, additional, Wu, Jiaxing, additional, Miao, Xiaofei, additional, Gao, Jia, additional, Xu, Xianning, additional, Liu, Yi, additional, Jiang, Jiamin, additional, Yang, Jiaqi, additional, Zhang, Jiaxin, additional, Shao, Tao, additional, Peng, Bo, additional, Ma, Huili, additional, Zhu, Dan, additional, Chen, Guojing, additional, Hu, Wenbo, additional, Li, Lin, additional, and Huang, Wei, additional

Published
2023
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30. Photostable Organic Two‐photon Dyes with Ultrahigh Brightness for Long‐term Fluorescence Imaging.

Author

Chen, Ruizhe, Pan, Yonghui, Wu, Zizi, Jia, Mingxuan, Miao, Xiaofei, Lu, Xiaomei, Fan, Quli, and Hu, Wenbo

Subjects
ORGANIC dyes, FLUORESCENCE, DYES & dyeing, FEMTOSECOND lasers, COUMARINS, PHOTOLUMINESCENCE, ORGANIC light emitting diodes
Abstract

Developing photostable two‐photon dyes with high brightness and negligible photocytotoxicity is of key importance in fluorescence imaging but remains a huge challenge. Here, a two‐photon dye with ultrahigh brightness and photostability is demonstrated for high‐performance long‐term two‐photon fluorescence imaging. By terminated donor engineering, the designed DBD shows a higher two‐photon absorption cross‐section (δ, 418 GM vs 329 GM) and photoluminescence quantum yield (ΦPL, 62.74% vs 54.63%) than its counterpart DBA. As a consequence, two‐photon fluorescence brightness (δ×ΦPL) of DBD exhibits a 10‐folded enhancement (262 GM vs 19 GM) in comparison with typical Coumarin 307 dye. More importantly, DBD displays ultrahigh photostability and negligible photobleaching under 10 min femtosecond laser irradiation, which stands in marked contrast to Coumarin 307. Furthermore, femtosecond transient absorption spectroscopy ascribes this ultrahigh photostability and negligible photobleaching to the inefficient intersystem crossing. With these merits, DBD can be used long‐term two‐photon fluorescence imaging in vitro. [ABSTRACT FROM AUTHOR]

Published
2023
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31. A Simple Aqueous Battery with Potential for Scalable Energy Storage Based on MnO 2 Deposition at the Cathode and a Quinoid‐Modified Activated Carbon Anode

Author

Miao Xiaofei, Zhang Xiangxin, Chen Sujing, Wei Wang, Chen Yuanqiang, Zhang Yining, Lin Junhong, Liu Yongchuan, and Chengwei Chen

Subjects
Battery (electricity), Materials science, Aqueous solution, Catalysis, Energy storage, Cathode, Anode, law.invention, Chemical engineering, law, Scalability, Electrochemistry, medicine, Deposition (phase transition), Activated carbon, medicine.drug
Published
2020
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34. Enhancing the Efficiency of Graphene Oxide Reduction in Low-Power Digital Video Disc Drives by a Simple Precursor Heat Treatment

Author

Feng Wendou, Wei Wang, Zhang Yining, Xin Li, Miao Xiaofei, and Lin Songyue

Subjects
Digital video disc, Materials science, business.industry, Graphene, Laser source, Oxide, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, 0104 chemical sciences, law.invention, Power (physics), Reduction (complexity), chemistry.chemical_compound, chemistry, law, Hardware_INTEGRATEDCIRCUITS, Optoelectronics, General Materials Science, Thin film, 0210 nano-technology, business
Abstract

Laser reduction of graphene oxide (GO) produces graphene effectively. As a low-power laser source, commercial digital video disc (DVD) drives provide a versatile platform to produce reduced graphene films in designed 2D patterns. However, research on how GO characteristics affect its laser reduction efficiency in DVD drives is rarely conducted. Here, we investigate how heating the GO dispersion affects the photoreduction process of GO films in a LightScribe DVD drive. Without noticeably changing the oxygen content, such mild heat treatment significantly improves GO's absorption in the visible region, resulting in significant enhancement on GO's laser reduction efficiency. We demonstrate that the laser reduction efficiency increases with the increasing treatment time. The enhanced reduction level greatly improves the performance of laser-scribed graphene electrodes in applications such as glucose sensors (with an optimal linear response range up to 2550 μM) and supercapacitors (with an optimal areal capacity of 1.37 mF cm

Published
2019
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35. Enhancing the capacity of activated carbon electrodes by a redox mediator pair for the fabrication of flexible asymmetric solid-state supercapacitors

Author

Fang Jianhui, Zhang Xiangxin, Chen Sujing, Liu Yongchuan, Chen Yuanqiang, Miao Xiaofei, Wei Wang, and Zhang Yining

Subjects
Supercapacitor, Fabrication, Materials science, Hydroquinone, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Redox, 0104 chemical sciences, chemistry.chemical_compound, Adsorption, Chemical engineering, chemistry, Electrode, medicine, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, 0210 nano-technology, Activated carbon, medicine.drug, Power density
Abstract

We use a redox mediator pair - hydroquinone (for positive electrode) and sodium anthraquinone-2-sulfonate (for negative electrode) - to treat the activated carbon electrodes for fabricating asymmetric supercapacitors. This simple adsorption-based treatment improves the specific capacity of the activated carbon electrode from 69.3 mAh g−1 to 300.4 mAh g−1 (negative electrode) and 63.5 mAh g−1 to 301.1 mAh g−1 (positive electrode). The charge balance between the two electrodes is achieved by synchronous potential measurements on redox reaction of hydroquinone and anthraquinone-2-sulfonate. Under 5 A g−1, the asymmetric supercapacitor delivers a high energy density of 37.1 Wh kg−1 with the power density of 2087 W kg−1. Meanwhile, the asymmetric supercapacitor demonstrates excellent cycling stability, capable of retaining 81.8% of its capacity after 20000 cycles at 10 A g−1. A flexible solid-state asymmetric supercapacitor is fabricated with the treated electrode-pair and exhibits excellent flexing stability, high volumetric energy density (2.20 mWh cm−3 at 0.017 W cm−3), and good cycling stability (>91% capacity retention after 3000 cycles), which holds great potential for application in wearable electronics.

Published
2019
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41. Viscosity Effects on Excited‐State Dynamics of Indocyanine Green for Phototheranostic.

Author

Liao, Keyue, Pan, Yonghui, Wu, Zizi, Yao, Weiyun, Miao, Xiaofei, Lu, Xiaomei, Fan, Quli, and Hu, Wenbo

Subjects
INDOCYANINE green, VISCOSITY, RADIATIVE transitions, PHOTODYNAMIC therapy, POWER density, MEASUREMENT of viscosity
Abstract

The excited‐state dynamics of indocyanine green (ICG) fundamentally determine its photophysical properties for phototheranostic. However, its dynamics are predictable to be susceptible toward intracellular viscosity due to its almost freely rotating structure, making the precise phototheranostic very challenging. Therefore, correlating the viscosity with the dynamics of ICG is of great importance and urgency for precise phototheranostic prospects. This study presents systemic investigations on the viscosity‐dependent dynamics of ICG for phototheranostic. Femtosecond transient absorption (fs‐TA) experiments elucidate a prolonged radiative transition (225 ps vs 152 ps) for ICG in a viscous environment, which benefits fluorescence. High viscosity remarkably extends the triplet excited‐state lifetime of ICG but reduces its internal conversion (6.2 ps vs 2.2 ps). The extended triplet lifetime affords sufficient photosensitization time to enhance photodynamic therapy. A moderative internal conversion is unfavorable for heat production, resulting in inferior photothermal therapy. With this clear picture of excitation energy state dissipation in mind, we readily identified the safety laser power density for precise phototheranostic. This work provides an insightful understanding of viscosity‐relevant excited‐state dynamics toward phototheranostic, which is also beneficial for designing novel ICG derivatives with improved phototheranostic performance. [ABSTRACT FROM AUTHOR]

Published
2022
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42. High performance flexible quasi-solid-state zinc-ion hybrid supercapacitors enable by electrode potential adjustment

Author

Miao Xiaofei, Wei Wang, Chen Yuanqiang, Liu Yongchuan, Chen Sujing, Zhang Yining, Lin Junhong, and Zhang Xiangxin

Subjects
Supercapacitor, Materials science, Renewable Energy, Sustainability and the Environment, business.industry, Cost effectiveness, Energy Engineering and Power Technology, chemistry.chemical_element, Zinc, Electrolyte, Energy storage, Anode, chemistry, Electrode, Optoelectronics, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, business, Electrode potential
Abstract

Rechargeable zinc-ion batteries have received increasing attention because of their cost effectiveness, eco-friendliness, and high capacity. However, they suffer from poor rate capacities and low lifespans because of the uncontrolled formation of zinc dendrite on the zinc metal anode. Although replacing the zinc metal negative electrode could fundamentally solve the dendritic problem, it may lead to the lack of anodic Zn2+ source to sustain the charge carriers during charge-discharge. Here, by adopting a pre-zincation electrode treatment, we demonstrate a novel zinc-ion hybrid supercapacitor (ZIS) by using GNS/CNT@MnO2 electrode and activated carbon electrode as the positive and negative electrode, respectively. The ZIS exhibits a high specific energy of 41.5 Wh kg−1 and excellent cycle stability. It retains over 81% of its initial capacitance and near 100% coulombic efficiency after 10000 cycles at 2 A g−1. We also create a Flexible Quasi-Solid-State Zinc-ion Hybrid Supercapacitor (FQSSZIS) by using a ZnSO4/MnSO4-xanthan gel electrolyte and cheap graphite paper current collectors. The obtained device exhibits excellent flexibility, good cycling stability, and a high energy density of 3.13 mWh cm−3 with a power density of 7 mW cm−3. The pre-zincation approach exhibits great potential for exploring zinc-ion energy storage devices without zinc metal electrodes.

Published
2021
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48. Layered-MnO2 Nanosheet Grown on Nitrogen-Doped Graphene Template as a Composite Cathode for Flexible Solid-State Asymmetric Supercapacitor

Author

Feng Wendou, Chen Sujing, Zhang Xiangxin, Chen Yuanqiang, Miao Xiaofei, Liu Yongchuan, Wei Wang, Zhang Yining, Wei Li, and Fang Jianhui

Subjects
Supercapacitor, Materials science, Graphene, Composite number, Nanotechnology, 02 engineering and technology, Current collector, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Capacitance, Cathode, 0104 chemical sciences, Anode, law.invention, law, General Materials Science, 0210 nano-technology, Nanosheet
Abstract

Flexible solid-state supercapacitors provide a promising energy-storage alternative for the rapidly growing flexible and wearable electronic industry. Further improving device energy density and developing a cheap flexible current collector are two major challenges in pushing the technology forward. In this work, we synthesize a nitrogen-doped graphene/MnO2 nanosheet (NGMn) composite by a simple hydrothermal method. Nitrogen-doped graphene acts as a template to induce the growth of layered δ-MnO2 and improves the electronic conductivity of the composite. The NGMn composite exhibits a large specific capacitance of about 305 F g–1 at a scan rate of 5 mV s–1. We also create a cheap and highly conductive flexible current collector using Scotch tape. Flexible solid-state asymmetric supercapacitors are fabricated with NGMn cathode, activated carbon anode, and PVA–LiCl gel electrolyte. The device can achieve a high operation voltage of 1.8 V and exhibits a maximum energy density of 3.5 mWh cm–3 at a power densit...

Published
2016
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