Advanced Electronic Materials
Công bố khoa học tiêu biểu
* Dữ liệu chỉ mang tính chất tham khảo
Sắp xếp:
Perovskite BiFeO<sub>3</sub>–BaTiO<sub>3</sub> Ferroelectrics: Engineering Properties by Domain Evolution and Thermal Depolarization Modification Abstract Bismuth ferrite (BFO)‐based ceramics with large electromechanical response are important in electronic device applications. To better understand their physical mechanisms, a new phase diagram established by temperature dependence of dielectric properties, temperature dependence of piezoelectric coefficient, and the evolution of their properties is proposed to explain the contribution of piezoelectric and strain response by comparing ferroelectric (FE) and relaxor ferroelectric (RFE) compositions. The FE components with macrodomains have large piezoelectric constant (d 33 of 412 pC/N) at high temperature. The RFE components with nanodomains possess giant strain response (S uni = 0.37%) at 180 °C. Combined with in situ and ex situ techniques, the physical mechanisms behind the enhancement of these properties are explored. Macrodomains and multipolar phase coexistence contribute to the piezoelectricity improvement. Nanodomains and an unstable depolarization temperature (T d ) region engineer the strain enhancement, which can promote electric‐field‐induced domain switching, lattice strain, and irreversible phase transition. In particular, the T d region of BiFeO3 ‐based ceramics has been ignored for several years, although it is actually an effective medium to engineer properties. The proposed phase diagram and dynamic model can be used to well understand the structural origins of large electromechanical properties in BFO‐based ceramics, which can give some guidance to explore materials with excellent properties for different applications.
Advanced Electronic Materials - Tập 6 Số 5 - 2020
Boosting the Thermoelectric Properties of PEDOT:PSS via Low‐Impact Deposition of Tin Oxide Nanoparticles Abstract Poly(3,4‐ethylenedioxy thiophene):poly(styrenesulfonate) (PEDOT:PSS) exhibits valuable characteristics concerning stability, green‐processing, flexibility, high electrical conductivity, and ease of property modulation, qualifying it as one of the most promising p‐type organic conductors for thermoelectric (TE) applications. While blending with inorganic counterparts is considered a good strategy to further improve polymeric TE properties, only a few attempts succeed so far due to inhomogeneous embedding and the non‐ideal organic‐inorganic contact. Here a new strategy to include nanoparticles (NPs) without any ligand termination inside PEDOT:PSS thin films is proposed. Spark discharge‐generated tin oxide NPs (SnOx x x −1 K−2 achieved is more than six times higher than the value found for the film without NPs. This easy and efficient strategy promises well for future mass production of flexible TE devices and the mechanism revealed may inspire future research on TEs and flexible electronics.
Advanced Electronic Materials - Tập 7 Số 5 - 2021
Mechanically Durable and Flexible Thermoelectric Films from PEDOT:PSS/PVA/Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> Nanocomposites Advances in organic thermoelectric materials have focused on the enhancement of mechanical property to address the limitations and needs of forming flexible and free‐standing films for the application of flexible/wearable thermoelectric devices. Herein, thermoelectric nanocomposite films are fabricated based on conductive polymer poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), plastic reinforcer polyvinyl alcohol (PVA), and inorganic Bi0.5 Sb1.5 Te3 thermoelectric nanocrystals with various contents. The resulting PEDOT:PSS/PVA/Bi0.5 Sb1.5 Te3 nanocomposite films exhibit a power factor of 47.7 µW m−1 K−2 and a ZT value of 0.05 at 300 K. More importantly, they are mechanically tough, yet very flexible with a tensile strength of 79.3 MPa and a fracture strain of 32.4%, which is sufficient to meet the required mechanical properties of textile manufacturing and body movements for flexible thermoelectric films, thus providing a substantial impact on future developments of flexible/wearable energy generation devices.
Advanced Electronic Materials - Tập 3 Số 4 - 2017
Morphologically Controlled Bioinspired Dopamine‐Polypyrrole Nanostructures with Tunable Electrical Properties In order to develop functional nanostructures with controllable size, composition, morphology, and interface, a series of dopamine (DA) modified polypyrrole (PPy) nanostructures that have tunable electrical conductivity and improved water dispersibility are prepared. The DA‐PPy nanostructures exhibit various morphologies, including nanosphere, nanofiber, nanorod, and nanoflake; and all of these nanostructures can be achieved by simply varying the DA/Py reacting mole ratio. Furthermore, the potential application of each as‐fabricated DA‐PPy, which depend on their tunable electrical properties, are explored. In particular, DA‐PPy resulting from a 0.032 dopamine/pyrrole (DA/Py) mole ratio demonstrate superior capacitance for supercapacitors; at DA/Py = 0.064, DA‐PPy can be implemented as a co‐filler into the epoxy network to prepare hybrid electrically conductive adhesives and DA‐PPy synthesized from 0.64 DA/Py mole ratio reveals impressive electromagnetic microwave absorption ability that can be used for electromagnetic interference shielding applications. Due to the synergetic effects of DA and electrically conductive polymer PPy, this one‐step procedure represents a promising protocol to control the syntheses and properties of nanomaterials for applications in advanced electronic devices.
Advanced Electronic Materials - Tập 1 Số 11 - 2015
Lead Replacement in CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> Perovskites Superior photovoltaic performance in organic–inorganic hybrid perovskite is based on the unique properties of each moiety contined within it. Identifying the role of metal atoms in the perovskite is of great importance to explore the low‐toxicity lead‐free perovskite solar cells. By using the first‐principle calculations, four types of AMX3 (A = CH3 NH3 , M = Pb, Sn, Ge, Sr, X = I) perovskite materials are investigated and an attempt is made to understand the structural and electronic influences of the metal atoms on the properties of perovskites. Then, the solutions to the replacement of Pb are discussed. It is found that for the small radius metal atoms as compared with Pb, the strong geometry distortion will result in a less p–p electron transition and larger carrier effective mass. The outer ns2 electrons of the metal ions play critical roles on the modulation of the optical and electronic properties for perovskite materials. These findings suggest that the solutions to the Pb replacement might be metal or metallic clusters that have effective ionic radius and outer ns2 electrons configuration on the metal ions with low ionization energy similar to Pb2+ . Based on this, lead‐free perovskite solar cells are expected to be realized in the near future.
Advanced Electronic Materials - Tập 1 Số 10 - 2015
Ultralow Electrical Hysteresis along with High Energy‐Storage Density in Lead‐Based Antiferroelectric Ceramics Abstract Antiferroelectric ceramics with extraordinary energy‐storage density have gained exponentially soaring attention for their applications in pulsed power capacitors. Nevertheless, high energy dissipation is a deficiency of antiferroelectric materials. The modulation of Ba/La‐doped (Pb0.91 Bax 0.06−2 x /3 )(Zr0.6 Sn0.4 )O3 (x = 0.015, 0.03, 0.045, 0.06) antiferroelectric ceramics is aimed at increasing the energy efficiency and obtaining an ideal energy storage density. The traditional solid‐state reaction is exploited for ceramics fabrication and all prepared samples exhibit an ultralow electrical hysteresis due to the local structural heterogeneity, as verified by Raman spectroscopy. Of particular importance is the fact that the (Pb0.91 Ba0.045 La0.03 )(Zr0.6 Sn0.4 )O3 ceramic possesses an excellent recoverable energy storage density (W rec = 8.16 J cm−3 ) and a remarkable energy efficiency (η = 92.1%) simultaneously under an electric field of 340 kV cm−1 . Moreover, the corresponding ceramic exhibits a superior discharge current density (C D = 1498.6 A cm−2 ), a high level of power density (P D = 202.3 MW cm−3 ), and a nanosecond‐level discharge period (53 ns). This provides a promising antiferroelectric material for fabricating ceramic capacitors with excellent energy storage and high power characteristics.
Advanced Electronic Materials - Tập 6 Số 4 - 2020
Si Doped Hafnium Oxide—A “Fragile” Ferroelectric System Abstract Silicon doped hafnium oxide was the material used in the original report of ferroelectricity in hafnia in 2011. Since then, it has been subject of many further publications including the demonstration of the world's first ferroelectric field‐effect transistor in the state‐of‐the‐art 28 nm technology. Though many studies are conducted with a strong focus on application in memory devices, a comprehensive study on structural stability in these films remains to be seen. In this work, a film thickness of about 36 nm, instead of the 10 nm used in most previous studies, is utilized to carefully probe how the concentration range impacts the evolution of phases, the dopant distribution, the field cycling effects, and their interplay in the macroscopic ferroelectric response of the films. Si:HfO2 appears to be a rather fragile system: different phases seem close in energy and the system is thus rich in competing phenomena. Nonetheless, it offers ferroelectricity or field‐induced ferroelectricity for elevated annealing conditions up to 1000 °C. Similar to the measures taken for conventional ferroelectrics such as lead zirconate titanate, engineering efforts to guarantee stable interfaces and stoichiometry are mandatory to achieve stable performance in applications such as ferroelectric memories, supercapacitors, or energy harvesting devices.
Advanced Electronic Materials - Tập 3 Số 10 - 2017
High Luminance Fiber‐Based Polymer Light‐Emitting Devices by a Dip‐Coating Method
Advanced Electronic Materials - Tập 1 Số 9 - 2015
Novel Scale‐Like Structures of Graphite/TiC/Ti<sub>3</sub>C<sub>2</sub> Hybrids for Electromagnetic Absorption Abstract Electromagnetic (EM) absorbing and shielding materials have attracted great interests due to the increasing electromagnetic pollutions in the past years. Microstructure plays a crucial role in determining the performance of the above materials. Herein, a scale‐like structure based on Ti3 C2 Mxenes is proposed to approach improved EM absorption properties. For the first time, graphite/TiC/Ti3 AlC2 (G/TiC/Ti3 AlC2 ) hybrids are fabricated in a molten salts bath and graphite/TiC/Ti3 C2 (G/TiC/Ti3 C2 ) hybrids are obtained after Al atoms are etched from G/TiC/Ti3 AlC2 . In G/TiC/Ti3 C2 , Ti3 C2 sheets are perpendicular to the plane of G/TiC, which like a bionic structure of fish scale. The scale‐like G/TiC/Ti3 C2 hybrids are dispersed in paraffin matrix to evaluate the EM properties. Owing to the structure‐induced EM absorption mechanism, G/TiC/Ti3 C2 show much enhanced EM absorption ability than those materials without structure design, e.g., G/TiC/Ti3 AlC2 , pure Ti3 C2 , G/TiC, and the simple mixture of G/TiC with Ti3 C2 (G/TiC+Ti3 C2 ). The minimum reflection coefficient (RC) of G/TiC/Ti3 C2 with the sample thickness of 2.1 mm reaches −63 dB and the effective absorption bandwidth (the frequency where RC is lower than −10 dB) is more than 3.5 GHz. The results indicate that the scale‐like structure can greatly improve the EM absorption ability.
Advanced Electronic Materials - Tập 4 Số 5 - 2018
Asymmetric Flexible MXene‐Reduced Graphene Oxide Micro‐Supercapacitor Abstract Current microfabrication of micro‐supercapacitors often involves multistep processing and delicate lithography protocols. In this study, simple fabrication of an asymmetric MXene‐based micro‐supercapacitor that is flexible, binder‐free, and current‐collector‐free is reported. The interdigitated device architecture is fabricated using a custom‐made mask and a scalable spray coating technique onto a flexible, transparent substrate. The electrode materials are comprised of titanium carbide MXene (Ti3 C2 Tx −3 at a power density of 0.2 W cm−3 . Further, these micro‐supercapacitors show a high level of flexibility during mechanical bending. Utilizing the ability of Ti3 C2 Tx 3 C2 Tx
Advanced Electronic Materials - Tập 4 Số 1 - 2018
Tổng số: 27
- 1
- 2
- 3