Mohammad Mahdi Tavakoli  Hadi Tavakoli Dastjerdi  Jiayuan Zhao  Katherine E. Shulenberger  Chiara Carbonera  Riccardo Po  Alessandra Cominetti  Gabriele Bianchi  Nathan D. Klein  Moungi G. Bawendi  Silvija Gradecak  Jing Kong 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(25)

Low carrier mobility and lifetime in semiconductor polymers are some of the main challenges facing the field of organic photovoltaics (OPV) in the quest for efficient devices with high current density. Finding novel strategies such as device structure engineering is a key pathway toward addressing this issue. In this work, the light absorption and carrier collection of OPV devices are improved by employment of ZnO nanowire (NW) arrays with an optimum NW length (50 nm) and antireflection (AR) film with nanocone structure. The optical characterization results show that ZnO NW increases the transmittance of the electron transporting layer as well as the absorption of the polymer blend. Moreover, the as‐deposited polymer blend on the ZnO NW array shows better charge transfer as compared to the planar sample. By employing PC70BM:PV2000 as a promising air‐stable active‐layer, power conversion efficiencies of 9.8% and 10.1% are achieved for NW devices without and with an AR film, indicating 22.5% and 26.2% enhancement in PCE as compared to that of planar device. Moreover, it is shown that the AR film enhances the water‐repellent ability of the OPV device.  相似文献   

    

Zhou Liu  Yuyan Zhang  Chengliu Chen  Tiyun Yang  Jidong Wang  Ling Guo  Peng Liu  Tiantian Kong 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(3)

Understanding the mechanical stability of granular‐armored liquid marbles is prerequisite for their applications including encapsulation, sensors, microreactions, and miniaturized liquid storage. Most liquid marbles are armored with agglomerated granular structure which complicates the wetting and interacting states of particles, hence, impeding one from understanding the effect of granular size on the mechanical stability of marbles. In this work, using a custom‐built platform to examine the liquid marbles armored by a single layer of uniform grains, it is revealed that larger microsized grains produce stronger liquid marble. This finding is attributed to the gravity‐induced capillary attraction which dominates the interaction of particles and provides additional tension to the granular network of the marble surface, which enhances the mechanical stability of marbles. In addition, different granular network structures are formed at the marble surface by using a binary mixture of monodisperse grains, and their effect on the mechanical stability of marbles is explored. The understandings offer important insights for application involving liquid marbles and provides guideline to formulate robust marble‐based products.  相似文献   

    

Yueqi Kong  Ashok Kumar Nanjundan  Yang Liu  Hao Song  Xiaodan Huang  Chengzhong Yu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(51)

Selenium (Se)‐based rechargeable aluminum batteries (RABs), known as aluminum–selenium (Al–Se) batteries, are an appealing new battery design that holds great promise for addressing the low‐capacity problem of current RAB technology. However, their applications are hindered by mediocre high‐rate capacity (≈100 mAh g^?1 at 0.5 A g^?1) and insufficient cycling life (50 cycles). Herein, the synthesis of mesoporous carbon fibers (MCFs) by coating mesoporous carbon with short‐length mesopores and tunable mesopore sizes (2.7 to 8.9 nm) coaxially on carbon nanotubes (CNT) is reported. When compositing MCFs with Se for Al–Se batteries, a positive correlation between mesopore size and electrolyte ion diffusivity is observed, however when pore size is increased to 8.9 nm, large voids are created at the interface of CNT core and mesoporous carbon shell, leading to decreased electrode conductivity. The trade‐off between ion diffusivity and interfacial connectivity/conductivity determines MCF with pore size of 7.1 nm as the best host material for Al–Se batteries. The composite cathode delivers high specific capacities (366 and 230 mAh g^?1 at 0.5 and 1 A g^?1), good rate performance, and excellent cycling stability (152 mAh g^?1 after 500 cycles at 2 A g^?1), superior over previously reported Se cathodes and other cathodes for RABs.  相似文献   

    

Mengya Kong  Yuyang Gu  Yulai Liu  Yibing Shi  Na Wu  Wei Feng  Fuyou Li 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(46)

For years, luminescence lifetime imaging has served as a quantitative tool in indicating intracellular components and activities. However, very few studies involve the in vivo study of animals, especially in vivo stimuli‐responsive activities of animals, as both excitation and emission wavelengths should fall into the near‐infrared (NIR) optical transparent window (660–950 and 1000–1500 nm). Herein, this work reports a lifetime‐responsive nanocomposite with both excitation and emission in the NIR I window (800 nm) and lifetime in the microsecond region. The incorporation of Tm³⁺‐doped rare‐earth nanocrystals and NIR dye builds an efficient energy transfer pathway that enables a tunable luminescence lifetime range. The NaYF₄:Tm nanocrystal, which absorbs and emits photons at the same energy level, is found to be 33 times brighter than optimized core–shell upconversion nanocrystals, and proved to be an effective donor for NIR luminescence resonance energy transfer (LRET). The anti‐interference capability of luminescence lifetime signals is further confirmed by luminescence and lifetime imaging. In vivo studies also verify the lifetime response upon stimulation generated in an arthritis mouse model. This work introduces an intriguing tool for luminescence lifetime–based sensing in the microsecond region.  相似文献   

    

Weiqian Kong  Xiaofan Zhang  Shuangshuang Liu  Yannan Zhou  Binbin Chang  Shouren Zhang  Hongbo Fan  Baocheng Yang 《Advanced Materials Interfaces》2019,6(1)

It is a serious challenge to develop photoanodes with fast charge separation efficiency and surface reaction kinetics. Herein, the N doped carbon dot modified WO₃ nanoflake (NCDs/WO₃) is constructed by impregnation method. The resulting NCDs/WO₃ exhibits an excellent photocurrent density of 1.42 mA cm⁻² (1.0 V vs saturated calomel electrode, SCE) in 1 m H₂SO₄ solution under AM 1.5 G irradiation, which is 2.25 times higher than that of the pristine WO₃. In addition, the onset potential of NCDs/WO₃ photoanode represents a cathodic shift of 70 mV, indicating the charge separation and transfer process are both promoted. These results demonstrate N doped CD modified WO₃ can further enhance the conductivity and electrochemical activity surface area, which contributes to the higher photoelectrochemical (PEC) performance. This work provides an efficient strategy for the development of doping carbon material with heteroatoms to increase the charge transfer and charge separation efficiency in PEC water oxidation.  相似文献   

    

Fu‐Gang Zhao  Bingyige Pan  Yu‐Ting Kong  Lei Dong  Cheng‐Min Hu  Ying‐Ji Sang  Xianjing Zhou  Biao Zuo  Xiaoping Dong  Benxia Li  Wei‐Shi Li 《Advanced Materials Interfaces》2019,6(5)

It is mostly reported that graphene lattice doped/codoped with heteroatoms (e.g., nitrogen and boron) in an in‐plane fashion exhibits an impressive oxygen reduction reaction (ORR) electrocatalytic efficiency when serving as a metal‐free catalyst, but the cases that graphene sheets functionalized with heteroatoms in an out‐plane scenario are rarely involved. Herein, amino (NH₂)‐/fluoro (F)‐cofunctionalized graphene (NH₂ G F) is rationally designed and synthesized both in out‐plane modes through a programmable substitutive/reductive defluorination toward bulk graphite fluoride using NaNH₂. Versatile NH₂‐/F‐(co)functionalized graphene products with tunable fluorination and amination are readily yielded and their ORR electrocatalysis is evaluated. Intriguingly, the parameter of NH₂/F molar ratio is determinative for their electrocatalytic performances. Consequently, graphene product (roughly formulated in (NH₂)_7.0 C₁₀₀ F_2.8, vide infra) dually functionalized with NH₂ and F and with an optimized NH₂/F factor of 2.5 outperforms others—overmuch in either NH₂ only or F only. Encouragingly, (NH₂)_7.0 C₁₀₀ F_2.8 even delivers a slightly better electrocatalytic activity than Pt/C catalyst. This finding implies a significant synergistic effect between NH₂ and F in boosting graphene electrocatalysis. Apart from fantastic electrocatalytic activity, (NH₂)_7.0 C₁₀₀ F_2.8 also exhibits remarkable resistance to crossover effect and exceptional cycling stability.  相似文献   

    

Xueyan Ren  Xue Zhang  Xin Zhai  Rongrong Deng  Jiahui Meng  Xingyan Li  Qingjun Kong 《Journal of Food Biochemistry》2019,43(11)

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Juzhong Tan  Silvana Martini  Ye Wang  Fanbin Kong  Richard Hartel  Gustavo Barbosa‐Cnovas  Bongkosh Vardhanabhuti  Gail Bornhorst  Silvia Keppler  Helen Joyner 《Journal of food science》2019,84(11):3204-3212

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Zhipeng Su  Yaru Qin  Kai Zhang  Yongguang Bi  Fansheng Kong 《Journal of food science》2019,84(6):1592-1599

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Hang Yin  Ka Lok Chiu  Pengqing Bi  Gang Li  Cenqi Yan  Hua Tang  Chujun Zhang  Yiqun Xiao  Hengkai Zhang  Wei Yu  Hanlin Hu  Xinhui Lu  Xiaotao Hao  Shu Kong So 《Advanced Electronic Materials》2019,5(10)

Operation stability remains the key hurdle for the best‐performing non‐fullerene small molecule acceptor (SMA)‐based organic photovoltaic (OPV) devices. Among all SMAs, the ITIC‐derivative is the most promising OPV cell using ITIC‐derivative acceptors with a power conversion efficiency > 15%. However, the operation stability of SMA‐based devices under illumination is relatively inferior when compared to bulk‐heterojunction (BHJ) cells that employ polymeric acceptors. Here, a polymer acceptor N2200 is used as the ternary component to study the device performance of ITIC‐derivative‐based PBDB‐T:ITIC‐M and PBDB‐T‐2F:IT‐4F BHJ solar cells, which currently are the representative state‐of‐the‐art high‐performance OPV devices. The ternary solar cells with low N2200 loading enjoy significantly improved operation stability, while maintaining a high power conversion efficiency. A comprehensive mechanism study is conducted on the ternary OPV systems in i) electronic and ii) thermal aspects. For i), the ternary BHJs show remarkably improved electron transport. For ii), the thermal diffusivity D of the ternary BHJ exhibits almost an order of magnitude improvement in D values, indicating that heat can be more effectively transferred out of such films than binary counterpart. The results show that N2200 ternary loading facilitates an improved network for both electron transport and heat dissipation, leading to improved photostability.  相似文献