| 1. |
- Liu, Xueqi, et al.
(author)
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Study on charge transportation in the layer-structured oxide composite of SOFCs
- 2018
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In: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12773-12781
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Journal article (peer-reviewed)abstract
- In the past few years, triple (H+/O2-/e(-)) conducting materials have been regarded as one of the most promising electrode categories for solid oxide fuel cells (SOFCs). In this work, a layer-structured LiNi0.8Co0.15Al0.05O2-delta (LNCA) with triple conduction has been studied. The semiconductor-ionic conductor (SIC) LNCA-SDC composite has been fabricated by compositing the LNCA material with ionic conductor, i.e., samarium doped ceria (SDC). The electrochemical performance of the LNCA-SDC composite was studied by electrochemical impedance spectroscopy, while its electronic conductivity was confirmed by d.c. polarization method. It is found that the ionic conductivity of the composite is higher than the electronic conductivity by several orders of magnitude. The charge carriers and transportation properties of LNCA-SDC were studied using H+ and O2- blocking layer cells respectively. Results prove that the LNCA-SDC composite is a hybrid oxygen ion-proton conducting material. The oxygen ion conduction is dominated at low temperature (425 -500 degrees C), however, it is comparable with H+ conduction at high temperature (550 degrees C). Additionally, the formation of Li2CO3 under fuel cell operation environment was observed and the mechanism of the hybrid conductivity of LNCA-SDC was studied.
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| 2. |
- Wang, Xunying, et al.
(author)
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La0.1SrxCa0.9-xMnO3-δ -Sm0.2Ce0.8O1.9 composite material for novel low temperature solid oxide fuel cells
- 2017
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In: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 42:27, s. 17552-17558
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Journal article (peer-reviewed)abstract
- Lowering the operating temperature of the solid oxide fuel cells (SOFCs) is one of the world R&D tendencies. Exploring novel electrolytes possessing high ionic conductivity at low temperature becomes extremely important with the increasing demands of the energy conversion technologies. In this work, perovskite La0.1SrxCa0.9-xMnO3-δ (LSCM) materials were synthesized and composited with the ionic conductor Sm0.2Ce0.8O1.9 (SDC). The LSCM-SDC composite was sandwiched between two nickel foams coated with semiconductorNi0.8Co0.15Al0.05LiO2- δ (NCAL) to form the fuel cell device. The strontium content in theLSCM and the ratios of LSCM to SDC in the LSCM-SDC composite have significant effects on the electrical properties and fuel cell performances. The best performance has been achieved from LSCM-SDC composite with a weight ratio of 2:3. The fuel cells showed OCV over 1.0 V and excellent maximum output power density of 800 mW/cm2 at 550 ºC. Device processes and ionic transport processes were also discussed.
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| 3. |
- Deng, Hui, et al.
(author)
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The electrolyte-layer free fuel cell using a semiconductor-ionic Sr2Fe1.5Mo0.5O6-delta - Ce0.8Sm0.2O2-delta composite functional membrane
- 2017
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In: International journal of hydrogen energy. - : Pergamon Press. - 0360-3199 .- 1879-3487. ; 42:39, s. 25001-25007
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Journal article (peer-reviewed)abstract
- Commercial double Perovskite Sr2Fe1.5Mo0.5O6-delta (SFM), a high performance and redox stable electrode material for solid oxide fuel cell (SOFC), has been used for the electrolyte (layer)-free fuel cell (EFFC) and also as the cathode for the electrolyte based SOFC in a comprehensive study. The EFFC with a homogeneous mixture of Ce0.8Sm0.2O2-delta (SDC) and SFM achieved a higher power density (841 mW cm(-2)) at 550 degrees C, while the SDC electrolyte based SOFC, using the SDC-SFM composite as cathode, just reached 326 mW cm(-2) at the same temperature. The crystal structure and the morphology of the SFM-SDC composite were characterized by X-ray diffraction analysis (XRD), and scanning electron microscope (SEM), respectively. The electrochemical impedance spectroscopy (EIS) results showed that the charge transfer resistance of EFFCs were much lower than that of the electrolyte-based SOFC. To illustrate the operating principle of EFFC, we also conducted the rectification characteristics test, which confirms the existence of a Schottky junction structure to avoid the internal electron short circuiting. This work demonstrated advantages of the semiconductor-ionic SDC-SFM material for advanced EFFCs.
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| 4. |
- Feng, Tongbao, et al.
(author)
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miR-124 inhibits cell proliferation in breast cancer through downregulation of CDK4
- 2015
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In: Tumor Biology. - : Springer Science and Business Media LLC. - 1423-0380 .- 1010-4283. ; 36:8, s. 5987-5997
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Journal article (peer-reviewed)abstract
- Studies have shown that microRNAs (miRNAs) are involved in the malignant progression of human cancer. However, little is known about the potential role of miRNAs in breast carcinogenesis. miR-124 expression in breast cancer tissue was measured by quantitative real-time PCR (qRT-PCR). Target prediction algorithms and luciferase reporter gene assays were used to investigate the target of miR-124. Breast cancer cells growth was regulated by overexpression or knockdown miR-124. At the end of the study, tumor-bearing mice were tested to confirm the function of miR-124 in breast cancer. In this study, we demonstrated that the expression of miR-124 was significantly downregulated in breast cancer tissues compared with matched adjacent non-neoplastic tissues. We identified and confirmed that cyclin-dependent kinase 4 (CDK4) was a direct target of miR-124. Overexpression of miR-124 suppressed CDK4 protein expression and attenuated cell viability, proliferation, and cell cycle progression in MCF-7 and MDA-MB-435S breast cancer cells in vitro. Overexpression of CDK4 partially rescued the inhibitory effect of miR-124 in the breast cancer cells. Moreover, we found that miR-124 overexpression effectively repressed tumor growth in xenograft animal experiments. Our results demonstrate that miR-124 functions as a growth-suppressive miRNA and plays an important role in inhibiting tumorigenesis by targeting CDK4.
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| 5. |
- Meng, Yuanjing, et al.
(author)
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High-performance SOFC based on a novel semiconductor-ionic SrFeO3-delta-Ce0.8Sm0.2O2-delta membrane
- 2018
-
In: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 43:28, s. 12697-12704
-
Journal article (peer-reviewed)abstract
- The semiconductor-ionic composite membrane has been recently developed for a novel solid oxide fuel cell (SOFC), i.e., the semiconductor-ion membrane fuel cell (SIMFC). In this work, the perovskite-type SrFeO3-delta (SFO) as semiconductor material was composited with ionic conductor Ce0.8Sm0.2O2-delta (SDC) to form the SFO-SDC composite membrane for SIMFCs. The SFO-SDC SIMFCs using the optimized weight ratio of 3:7 SFO-SDC membrane obtained the best performances, 780 mW cm(-2) at 550 degrees C, compared to 348 mW cm(-2) obtained from the pure SDC electrolyte fuel cell. Introduction of SFO into SDC can extend the triple phase boundary and provide more active sites for accelerating the fuel cell reactions, thus significantly enhanced the cell power output. Moreover, SFO was employed as the cathode, and a higher power output, 907 mW cm(-2) was achieved, suggesting that SFO cathode is more compatible for the SFO-SDC system in SIMFCs. This work provides an attractive strategy for the development of low temperature SOFCs.
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| 6. |
- Qing, Jian, et al.
(author)
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High-Quality Ruddlesden-Popper Perovskite Films Based on In Situ Formed Organic Spacer Cations
- 2019
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In: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 31:41
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Journal article (peer-reviewed)abstract
- Ruddlesden-Popper perovskites (RPPs), consisting of alternating organic spacer layers and inorganic layers, have emerged as a promising alternative to 3D perovskites for both photovoltaic and light-emitting applications. The organic spacer layers provide a wide range of new possibilities to tune the properties and even provide new functionalities for RPPs. However, the preparation of state-of-the-art RPPs requires organic ammonium halides as the starting materials, which need to be ex situ synthesized. A novel approach to prepare high-quality RPP films through in situ formation of organic spacer cations from amines is presented. Compared with control devices fabricated from organic ammonium halides, this new approach results in similar (and even better) device performance for both solar cells and light-emitting diodes. High-quality RPP films are fabricated based on different types of amines, demonstrating the universality of the approach. This approach not only represents a new pathway to fabricate efficient devices based on RPPs, but also provides an effective method to screen new organic spacers with further improved performance.
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| 7. |
- Wang, Baoyuan, et al.
(author)
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Photovoltaic properties of LixCo3-xO4/TiO2 heterojunction solar cells with high open-circuit voltage
- 2016
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 157, s. 126-133
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Journal article (peer-reviewed)abstract
- All-oxide solar cells are presently attracting extensive research interest due to their excellent stability, low-cost and non-toxicity. However, the band gap of metal oxides is lack of effective optimization and results in poor photovoltaic performance, thus hindering their practical applications. In this work, Co3O4 was investigated for application as a photo-absorber in all-oxide solar cells, and its band gap was optimized by introducing Li dopant into the spinel structure. LixCo3-xO4 nanoparticles, prepared via the hydrothermal method, were homogenously coated onto TiO2 mesoporous films, which were then used to fabricate planar heterojunction TiO2/LixCo3-xO4 solar cells (SCs). The effects of Li-doping on the heterojunction solar cell performance were further investigated. The findings revealed that the incorporation of Li ions into Co3O4 led to a significant enhancement in short-circuit current density (J(sc)). Remarkably, a high open-circuit voltage (V-oc) of 0.70 V was also achieved. Besides, reasons for the enhanced cell performance are the narrower band gap, reduced photogenerated carrier recombination and the more favorable energy band structure as compared with SCs assembled from pure Co3O4.
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| 8. |
- Wang, Baoyuan, et al.
(author)
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Semiconductor-ionic Membrane of LaSrCoFe-oxide-doped Ceria Solid Oxide Fuel Cells
- 2017
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 248, s. 496-504
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Journal article (peer-reviewed)abstract
- A novel semiconductor-ionic La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-Sm/Ca co-doped CeO2 (SCDC) nanocomposite has been developed as a membrane, which is sandwiched between two layers of Ni0.8Co0.15Al0.05Li-oxide (NCAL) to construct semiconductor-ion membrane fuel cell (SIMFC). Such a device presented an open circuit voltage (OCV) above 1.0 V and maximum power density of 814 mW cm(-2) at 550 degrees C, which is much higher than 0.84 V and 300 mW cm(-2) for the fuel cell using the SCDC membrane. Moreover, the SIMFC has a relatively promising long-term stability, the voltage can maintain at 0.966 V for 60 hours without degradation during the fuel cells operation and the open-circuit voltage (OCV) can return to 1.06 V after long-term fuel cell operation. The introduction of LSCF electronic conductor into the membrane did not cause any short circuit but brought significant enhancement of fuel cell performances. The Schottky junction is proposed to prevent the internal electrons passing thus avoiding the device short circuiting problem.
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| 9. |
- Wang, Yaling, et al.
(author)
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Enhanced performance and stability of inverted planar perovskite solar cells by incorporating 1,6-diaminohexane dihydrochloride additive
- 2018
-
In: Solar Energy Materials and Solar Cells. - : ELSEVIER SCIENCE BV. - 0927-0248 .- 1879-3398. ; 188, s. 140-148
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Journal article (peer-reviewed)abstract
- Herein, 1,6-Diaminohexane Dihydrochloride (1,6-DD) is introduced into perovskite precursors to fabricate the inverted planar perovskite solar cells. By regulating the concentration of 1,6-DD additive, the average power conversion efficiency (PCE) of perovskite solar cells is enhanced by 20%. The champion device achieves a relatively high PCE of 17% and an excellent fill factor of 80.1%. The PCE of the large-area (1 cm(2)) device also reaches to 13.68%. After exposure to the air for 16 days, the device with 1,6-DD additive still retains above 90% of the initial efficiency, exhibiting good stability. We demonstrate that a small amount of 1,6-DD affects the crystallization dynamic, yielding ideal perovskite film with enhanced crystallinity and enlarged grain size. The two terminal -NH3+ groups passivates the vacancy defects at the perovskite crystal surface, suppressing charge recombination and facilitating charge transportation effectively. Meanwhile, adjacent crystal surfaces are linked through the hexane alkyl chain of 1,6-DD molecule, which enhances the interaction between perovskite grains and anchors the microstructure of perovskite to some degree. Hydrophobic hexane alkyl chains also increase the moisture resistance of perovskite film. Thus, an easy and effective way is provided for fabricating efficient and stable perovskite solar cells.
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| 10. |
- Xu, Weidong, 1988-, et al.
(author)
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Rational molecular passivation for high-performance perovskite light-emitting diodes
- 2019
-
In: Nature Photonics. - : Springer Nature Publishing AG. - 1749-4885 .- 1749-4893. ; 13:6, s. 418-424
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Journal article (peer-reviewed)abstract
- A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.
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