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Emerging Transparent Conducting Electrodes for Organic Light Emitting Diodes

Author(s):Tze-Bin Song -- Ning Li
Journal: Electronics
Publisher:
Abstract
| Pages: 190-204
Organic light emitting diodes (OLEDs) have attracted much attention in recent years as next generation lighting and displays, due to their many advantages, including superb performance, mechanical flexibility, ease of fabrication, chemical versatility, etc. In order to fully realize the highly flexible features, reduce the cost and further improve the performance of OLED devices, replacing the conventional indium tin oxide with better alternative transparent conducting electrodes (TCEs) is a crucial step. In this review, we focus on the emerging alternative TCE materials for OLED applications, including carbon nanotubes (CNTs), metallic nanowires, conductive polymers and graphene. These materials are selected, because they have been applied as transparent electrodes for OLED devices and achieved reasonably good performance or even higher device performance than that of indium tin oxide (ITO) glass. Various electrode modification techniques and their effects on the device performance are presented. The effects of new TCEs on light extraction, device performance and reliability are discussed. Highly flexible, stretchable and efficient OLED devices are achieved based on these alternative TCEs. These results are summarized for each material. The advantages and current challenges of these TCE materials are also identified.

Bottom-Up, Wet Chemical Technique for the Continuous Synthesis of Inorganic Nanoparticles

Author(s):Annika Betke -- Guido Kickelbick
Journal: Inorganics
Publisher:
Abstract
| Pages: 1-15
Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO), magnetite (Fe3O4), as well as brushite (CaHPO4·2H2O), particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.

Investigation into the Incorporation of Phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In)

Author(s):Alaric D. Smith -- Peter R. Slater
Journal: Inorganics
Publisher:
Abstract
| Pages: 16-28
In this paper we examine the effect of doping phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In). The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results showed that phosphate could be incorporated into this system up to the 10% doping level, although this required an increased Y/Yb/In content, e.g., BaCe0.6(Y/In/Yb)0.3P0.1O2.9. The phosphate doping was, however, shown to lead to a decrease in conductivity; although at low phosphate levels high conductivities were still observed, e.g., for BaCe0.65Y0.3P0.05O2.875, σ = 4.3 × 10−3 S cm−1 at 600 °C in wet N2. In terms of the effect of phosphate incorporation on the CO2 stability, it was shown to lead to a small improvement for the In containing samples, whereas the yttrium doped compositions showed no change in CO2 stability.

Chemistry of Ammonothermal Synthesis

Author(s):Theresia M. M. Richter -- Rainer Niewa
Journal: Inorganics
Publisher:
Abstract
| Pages: 29-78
Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN), amides (e.g., LiNH2, Zn(NH2)2), imides (e.g., Th(NH)2), ammoniates (e.g., Ga(NH3)3F3, [Al(NH3)6]I3 · NH3) and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs2Te5). In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus.

New Type-I and Type-II Clathrates in the Systems Cs–Na–Ga–Si, Rb–Na–Ga–Si, and Rb–Na–Zn–Si

Author(s):Marion C. Schäfer -- Svilen Bobev
Journal: Inorganics
Publisher:
Abstract
| Pages: 79-95
Systematic studies in the systems Cs–Na–Ga–Si, Rb–Na–Ga–Si, and Rb–Na–Zn–Si yielded the novel type-I clathrates with refined compositions Cs6Na2Ga8.25Si37.75(3), Rb6.34Na1.66(2)Ga8.02Si37.98(3), and Rb5.20Na2.80(4)Zn3.85Si42.15(2) (cubic, ), as well as the type-II clathrates with formulae Cs8Na16Ga22.7Si113.3(1), Rb8.4Na15.6(1)Ga19.6Si116.4(1), and Rb8Na16Zn8.4Si127.6(1) (cubic, ). In each system, the type-I and -II compounds are always co-crystallizing, irrespective of the reaction conditions. The structures derived from single-crystal X-ray diffraction confirm complete ordering of Cs and Na atoms, and nearly complete ordering of the Rb and Na guest atoms. The framework-building Si atoms are randomly substituted by Ga or Zn atoms on all framework sites with notable difference in the substitution patterns between the type-I and type-II structure. This, and other details of the crystal chemistry are discussed in this paper.

Syntheses of Macromolecular Ruthenium Compounds: A New Approach for the Search of Anticancer Drugs

Author(s):Andreia Valente -- M. Helena Garcia
Journal: Inorganics
Publisher:
Abstract
| Pages: 96-114
The continuous rising of the cancer patient death rate undoubtedly shows the pressure to find more potent and efficient drugs than those in clinical use. These agents only treat a narrow range of cancer conditions with limited success and are associated with serious side effects caused by the lack of selectivity. In this frame, innovative syntheses approaches can decisively contribute to the success of “smart compounds” that might be only selective and/or active towards the cancer cells, sparing the healthy ones. In this scope, ruthenium chemistry is a rising field for the search of proficient metallodrugs by the use of macromolecular ruthenium complexes (dendrimers and dendronized polymers, coordination-cage and protein conjugates, nanoparticles and polymer-“ruthenium-cyclopentadienyl” conjugates) that can take advantage of the singularities of tumor cells (vs. healthy cells).

Diarylplatinum(II) Compounds as Versatile Metallating Agents in the Synthesis of Cyclometallated Platinum Compounds with N-Donor Ligands

Author(s):Margarita Crespo
Journal: Inorganics
Publisher:
Abstract
| Pages: 115-131
This review deals with the reactions of diarylplatinum(II) complexes with N-donor ligands to produce a variety of cycloplatinated compounds including endo-five-, endo-seven-, endo-six- or exo-five-membered platinacycles. The observed reactions result from a series of oxidative addition/reductive elimination processes taking place at platinum(II)/platinum(IV) species and involving C–X (X = H, Cl, Br) bond activation, arene elimination, and, in some cases, Caryl–Caryl bond formation.

Comparative Issues of Cathode Materials for Li-Ion Batteries

Author(s):Christian M. Julien -- Alain Mauger -- Karim Zaghib -- Henri Groult
Journal: Inorganics
Publisher:
Abstract
| Pages: 132-154
After an introduction to lithium insertion compounds and the principles of Li-ion cells, we present a comparative study of the physical and electrochemical properties of positive electrodes used in lithium-ion batteries (LIBs). Electrode materials include three different classes of lattices according to the dimensionality of the Li+ ion motion in them: olivine, layered transition-metal oxides and spinel frameworks. Their advantages and disadvantages are compared with emphasis on synthesis difficulties, electrochemical stability, faradaic performance and security issues.

Dissolved Gas Analysis of Power Transformers

Author(s):Sadeq Yasoob Jasim -- Jyoti Shrivastava
Journal: International Journal of Electrical and Electronics Engineering Research
Publisher:TJPRC Pvt Ltd.
Abstract
| Pages: 1-10
Transformer insulation aging diagnosis is important for all the condition assessment Dissolved gas analysis (DGA) is one of the most useful techniques and tools to detect the incipient faults in large oil filled transformers. Various methods have been developed to interpret DGA results. Among them are the Key Gas, Rogers Ratio, Logarithmic Nomo graph, Dorenenburg, IEC Ratio and Duval Triangle. This paper uses the DGA data from different cases to test the accuracy and consistency of these methods in interpreting the transformer condition. It also describes the structure and specific features of transformer insulation ageing diagnosis based on artificial neural networks. MATLAB programs using neural network were developed to automate. Also this paper present three fault type, partial discharges (PD), discharges, thermal faults.
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