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排序方式: 共有3134条查询结果,搜索用时 15 毫秒
41.
Lisi Yang Shuaishuai Shen Xiang Chen Huan Wei Dongdong Xia Chaowei Zhao Ningfang Zhang Yuanyuan Hu Weiwei Li Hao Xin Jinsheng Song 《Advanced functional materials》2023,33(36):2303603
The electron transport layer (ETL) is a critical component in achieving high device performance and stability in organic solar cells. Conjugated polyelectrolytes (CPEs) have become an attractive alternative due to film-forming properties and ease of preparation. However, p-type CPEs generally exhibit poor charge mobility and conductivity, incorporation of electron-withdrawing units forming alternated D-A conjugated backbone can make up for these deficiencies. Herein, the ratio of electron withdrawing moieties are further increased and two poly(A1-alt-A2) typed PIIDNDI-Br and PDPPNDI-Br based on the combination of naphthalene diimide (NDI) with isoindigo (IID) or diketopyrrolopyrrole (DPP) via direct arylation polycondensation are synthesized. These CPEs possess excellent alcohol solubility, a suitable lowest unocuppied molecular orbital energy level, and work function tunability. Surprisingly, the incorporation of IID and DPP units generate distinct self-doping behaviors, which are confirmed by UV–vis absorption and ESR spectra. However, no matter doped or undoped, both CPEs present better charge-transporting properties and conductivity when utilized as ETLs. The PIIDNDI-Br and PDPPNDI-Br display good universal compatibility with the blend of PM6:Y6 and PM6:L8-BO, and PCEs of 18.32% and 18.36% are obtained, respectively, which also present excellent storage stability. In short, the combination of two different acceptors demonstrates an efficient strategy to design highly efficient ETLs for high performance photovoltaic devices. 相似文献
42.
Mengmeng Liu Xiaohang Zhu Yujie Song Guanlin Huang Jiamin Wei Xiaokai Song Qi Xiao Tao Zhao Wan Jiang Xiaopeng Li Wei Luo 《Advanced functional materials》2023,33(11):2213395
Oxygen reduction reaction (ORR) and sulfur reduction reaction (SRR) play key roles in advanced batteries. However, they both suffer from sluggish reaction kinetics. Here, an interesting nitrogen doped porous carbon material that can simultaneously activate oxygen and sulfur is reported. The carbon precursor is a nitrogen containing covalent organic framework (COF), constituting periodically stacked 2D sheets. The COF structure is well preserved upon pyrolysis, resulting in the formation of edge-rich porous carbon with structure resembling stacked holey graphene. The nitrogen containing groups in the COF are decomposed into graphitic and pyridinic nitrogen during pyrolysis. These edge sites and uniform nitrogen doping endow the carbon product with high intrinsic catalytic activities toward ORR and SRR. The COF derived carbon delivers outstanding performances when assembling as cathodes in the Li-S and Li-O2 batteries. Simultaneous activation of oxygen and sulfur also enables a new battery chemistry. A proof-of-concept Li-S/O2 hybrid battery is assembled, delivering a large specific capacity of 2,013 mAh g−1. This study may inspire novel battery designs based on oxygen and sulfur chemistry. 相似文献
43.
Reducing Hysteresis and Enhancing Performance of Perovskite Solar Cells Using Low‐Temperature Processed Y‐Doped SnO2 Nanosheets as Electron Selective Layers
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Guang Yang Hongwei Lei Hong Tao Xiaolu Zheng Junjie Ma Qin Liu Weijun Ke Zhiliang Chen Liangbin Xiong Pingli Qin Zhao Chen Minchao Qin Xinhui Lu Yanfa Yan Guojia Fang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(2)
Despite the rapid increase of efficiency, perovskite solar cells (PSCs) still face some challenges, one of which is the current–voltage hysteresis. Herein, it is reported that yttrium‐doped tin dioxide (Y‐SnO2) electron selective layer (ESL) synthesized by an in situ hydrothermal growth process at 95 °C can significantly reduce the hysteresis and improve the performance of PSCs. Comparison studies reveal two main effects of Y doping of SnO2 ESLs: (1) it promotes the formation of well‐aligned and more homogeneous distribution of SnO2 nanosheet arrays (NSAs), which allows better perovskite infiltration, better contacts of perovskite with SnO2 nanosheets, and improves electron transfer from perovskite to ESL; (2) it enlarges the band gap and upshifts the band energy levels, resulting in better energy level alignment with perovskite and reduced charge recombination at NSA/perovskite interfaces. As a result, PSCs using Y‐SnO2 NSA ESLs exhibit much less hysteresis and better performance compared with the cells using pristine SnO2 NSA ESLs. The champion cell using Y‐SnO2 NSA ESL achieves a photovoltaic conversion efficiency of 17.29% (16.97%) when measured under reverse (forward) voltage scanning and a steady‐state efficiency of 16.25%. The results suggest that low‐temperature hydrothermal‐synthesized Y‐SnO2 NSA is a promising ESL for fabricating efficient and hysteresis‐less PSC. 相似文献
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Trifunctional Electrocatalysts: Graphene Composites with Cobalt Sulfide: Efficient Trifunctional Electrocatalysts for Oxygen Reversible Catalysis and Hydrogen Production in the Same Electrolyte (Small 33/2017)
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46.
Graphene Composites with Cobalt Sulfide: Efficient Trifunctional Electrocatalysts for Oxygen Reversible Catalysis and Hydrogen Production in the Same Electrolyte
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Nan Wang Ligui Li Dengke Zhao Xiongwu Kang Zhenghua Tang Shaowei Chen 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(33)
Nitrogen and sulfur‐codoped graphene composites with Co9S8 (NS/rGO‐Co) are synthesized by facile thermal annealing of graphene oxides with cobalt nitrate and thiourea in an ammonium atmosphere. Significantly, in 0.1 m KOH aqueous solution the best sample exhibits an oxygen evolution reaction (OER) activity that is superior to that of benchmark RuO2 catalysts, an oxygen reduction reaction (ORR) activity that is comparable to that of commercial Pt/C, and an overpotential of only ?0.193 V to reach 10 mA cm?2 for hydrogen evolution reaction (HER). With this single catalyst for oxygen reversible electrocatalysis, a potential difference of only 0.700 V is observed in 0.1 m KOH solution between the half‐wave potential in ORR and the potential to reach 10 mA cm?2 in OER; in addition, an overpotential of only 450 mV is needed to reach 10 mA cm?2 for full water splitting in the same electrolyte. The present trifunctional catalytic activities are markedly better than leading results reported in recent literature, where the remarkable trifunctional activity is attributed to the synergetic effects between N,S‐codoped rGO, and Co9S8 nanoparticles. These results highlight the significance of deliberate structural engineering in the preparation of multifunctional electrocatalysts for versatile electrochemical reactions. 相似文献
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49.
Zhaoxia CaiAuthor VitaeGuoxiang ChenAuthor Vitae Xi HuangAuthor VitaeMeihu MaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):368-373
A new method for the determination of lysozyme with high sensitivity based on Resonance Rayleigh scattering (RRS) by using Cd doped ZnSe quantum dots (QDs) as a probe was proposed in this experiment. Cd doped ZnSe QDs capped with glutathione were prepared in the water phase. Further, the RRS spectrum, transmission electron microscope, and absorption spectrum of the QDs-lysozyme system have been characterized. In addition, the effects of several factors on scattering intensities were investigated, including pH value of solution, amount of QDs, mixing sequence of each reagent and the coexisting substances. Moreover, the possible mechanism for the RRS enhancement of Cd doped ZnSe QDs-lysozyme system was preliminary discussed. The RRS method for the determination of lysozyme has good sensitivity with the detection limits 6.5 × 10−10 g mL−1. The contents of lysozyme were determined with recoveries of 97.1-101.6% and relativity standard deviation of 2.5-3.1%, respectively. It proved that the method established in our study is very sensitive, rapid, convenient and tolerant for the determination of lysozyme in synthetically and chicken egg white. 相似文献
50.
Enhanced charge generation in doped organic/organic p–n heterojunction for improving the performance of tandem organic light emitting diode
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Dashan Qin Wei Zhao Li Chen Zhihua Shi Huan Cao 《Journal of the Society for Information Display》2017,25(5):337-342
The doped organic/organic p–n heterojunctions have been applied as charge generation structure (CGS) in tandem organic light emitting diodes (TOLEDs). It is found that the field‐induced charge generation takes place more efficiently at the interface between Li2CO3 n‐doped bathocuproine (BCP:Li2CO3) and MoO3 p‐doped 4,4′‐N ,N′‐dicarbazole‐biphenyl (CBP:MoO3) than at the interface between BCP:Li2CO3 and MoO3 p‐doped 4,4‐bis[N‐1‐naphthyl‐N‐phenylamino]biphenyl (NPB:MoO3). It is because the process of electrons tunneling through the depletion zone from the highest occupied molecular orbit (HOMO) of CBP:MoO3 to the lowest unoccupied molecular orbit (LUMO) of BCP:Li2CO3 is more efficient than that from the HOMO of NPB:MoO3 to the LUMO of BCP:Li2CO3. Compared to the TOLED using the conventional CGS of 10‐nm BCP:Li2CO3/20‐nm NPB:MoO3, the one using the CGS of 10‐nm BCP:Li2CO3/10‐nm CBP:MoO3/10‐nm NPB:MoO3 shows increased device performance. In addition, the interconnecting property of CGS of 10‐nm BCP:Li2CO3/x nm CBP:MoO3/20 ? x nm NPB:MoO3 shows a strong dependence on the thickness of CBP:MoO3. We provide a new insight on optimizing Ohmic loss in the CGSs, useful for improving the performance of TOLEDs. 相似文献