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Block copolymers have unique associative properties that facilitate self-assembly into nanostructures that have been widely used in soft lithography, [1] templating, [2] drug delivery, [3] biomedical, [4,5] and chemical catalytic [6] applications. Of special interest is the in situ preparation of metallic or semiconducting nanoparticles in amphiphilic block copolymers. [7][8][9][10][11][12] The synthesis of nanoparticles in block copolymer micelles solves the problem of particle size control and stabilization compared to classical stabilization systems that employ surfactants [13][14][15] or microemulsions. [16,17] Nanocrystal-based organic memories [18][19][20][21] are attracting widespread interest owing to their simple structure and the prospect of creating 2D/3D stacks of these memory cells for increased bit densities. Recent reviews [20,22,28] summarize the literature for these nanoparticle-based organic memories comprehensively, and have identified the main operating mechanisms to be one of the following: (i) an electricfield-induced charge transfer between the nanoparticles and the surrounding conjugated compounds, [19,22] (ii) filamentary conduction, [23,24] (iii) charge trapping-detrapping, [25,26] and (iv) space-charge field inhibition of injection in the nanoparticles through a high-voltage pulse. [20,27] Besides the widely used two-terminal bistable organic memory devices, an alternative memory architecture that can be adopted is based on an organic thin-film transistor (OTFT) with a non-volatile floating gate memory [29] which allows a direct integration of the memory element with the transistor for integrated circuit applications. The ability to have a one-step fabrication process to generate arrays of metallic nanoparticles using solutionprocessing methods makes this approach amenable to potential implementations in the nanoparticle-based organic memory devices mentioned above. This is in contrast to past designs of organic memory devices, which involved the use of multistep approaches of presynthesizing nanoparticles followed by surface modification to prevent agglomeration prior to embedding them in multiple functional layers through solution processing or physical vapor deposition. Furthermore, this solution-processing approach is especially suitable for low-cost, large-area processing on flexible substrates, which may be considered to be the cornerstone of organic electronics applications. We demonstrate herein, for the first time, a polymeric memory that comprises an in situ synthesis strategy of gold nanoparticles in polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP). This system serves as a prototype for a generic memory device using nanoparticles as floating gate charge storage centers and, in particular, for integration into OTFT-based circuits. The block copolymer micelles turn out to be an excellent model system that is simple, forms a self-assembled ordered nanostructure, and provides optimum control over nanoparticle size formation and isolation. The response of the memory device is c...

Deposition process of Cr species at the ͑La,Sr͒͑Co,Fe͒O 3 ͑LSCF͒ electrode and Gd 0.2 Ce 0.8 O 2 ͑GDC͒ electrolyte system is investigated under the O 2 reduction conditions in the presence of a Fe-Cr alloy interconnect for solid oxide fuel cells. Deposition of Cr species preferentially occurs on the surface of the LSCF electrode with and without the cathodic polarization at 900°C, forming SrCrO 4 and Cr 2 O 3 phase. At the initial stage of the reaction, Cr deposition was not detected inside the LSCF electrode or at the LSCF electrode/GDC electrolyte interface. Deposition of Cr species on the LSCF electrode surface under the rib of Fe-Cr alloy interconnect is substantial in comparison to that under the channel of the interconnect. The results demonstrate clearly that the deposition of Cr species at the LSCF electrode is essentially a chemical reaction and is kinetically controlled by nucleation reaction between the gaseous Cr species and SrO-enriched/segregated on the LSCF electrode surface.Solid oxide fuel cells ͑SOFCs͒ are an environmentally friendly and most efficient power generation technology with very low greenhouse gas emission. The use of metals, especially chromiaforming ferrite stainless steel, as interconnect for SOFCs is desirable because of their high thermal and electronic conductivity, negligible ionic conductivity, good machinability, and low material cost. 1 However, the application of these chromia-forming alloys as interconnect poses many challenges even at reduced temperatures. The oxide scale formed on the surface of the alloy results in high electrical resistance and causes degradation of the stack performance. [2][3][4] Furthermore, under high temperatures volatile Cr species such as CrO 3 and CrO 2 ͑OH͒ 2 are generated over the oxide scale layer in oxidizing atmospheres. 5,6 It is well known that without effective protective coating, the generated gaseous Cr species generated can cause rapid performance deterioration in SOFCs due to the poisoning of the cathodes such as ͑La,Sr͒MnO 3 ͑LSM͒ for the O 2 reduction reaction. 7-10 We studied in detail the mechanism and kinetics of the deposition of Cr species at the LSM electrodes under SOFC operation conditions. 11-14 The Cr species preferentially deposit at the LSM electrode/Y 2 O 3 -ZrO 2 electrolyte interface region, forming deposit bands or rings on the yttria-stabilized zirconia ͑YSZ͒ electrolyte surface close to the edge of the LSM electrode. The deposition process is essentially dominated by the chemical dissociation of the gaseous Cr species and is most likely limited by the nucleation reaction between gaseous Cr species and nucleation agent, e.g., the manganese species ͑Mn 2+ ͒ generated under cathodic polarization or at high temperatures in the LSM electrode/zirconia electrolyte system. 12 Further study shows that the Cr deposition process strongly depends on the nature of electrode materials. 15 ͑La,Sr͒͑Co,Fe͒O 3 ͑LSCF͒ perovskite material has been extensively investigated and considered as one of the most promising cathode candidate...

A synchronous reduction and assembly strategy is designed to fabricate large-area graphene films and patterns with tunable transmittance and conductivity. Through an oxidation-reduction reaction between the metal substrate and graphene oxide, graphene oxide is reduced to chemically converted graphene and is organized into highly ordered films in situ. This work will form the precedent for industrial-scale production of graphene materials for future applications in electronics and optoelectronics.

We report the intrinsic room-temperature ferromagnetism in undoped ZnO nanoparticles with different sizes synthesized by a wet chemical method at different temperatures. Electron paramagnetic resonance, X-ray photoelectron spectroscopy, and photoluminescence measurements demonstrate clearly the singly charged oxygen vacancies are the main defects, and the relative occupancy of that decreases with increasing sizes and annealing temperatures. Importantly, a direct correlation between the ferromagnetism and the relative concentration of the singly charged oxygen vacancies is established, which suggests that the singly charged oxygen vacancies play a crucial role in modulating ferromagnetic behaviors. Moreover, the size-dependent ferromagnetism can be manipulated conveniently by changing of the surface–volume ratio, which is in favor of future electronic and spintronic application.

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