Recent progresses on solution-processed silver nanowire based transparent conducting electrodes for organic solar cells

Organic photovoltaics (OPVs) are considered as a future alternative for conventional silicon based solar cells, owing to their low cost, ease of production and high-throughput. The transparent conducting electrode (TCE) is a fundamental component of OPVs. Traditionally, indium tin oxide (ITO) has been mainly utilized as a TCE in OPV applications due to its relatively high transparency and low sheet resistance. However, increasing demand for the optoelectronic devices has led to large fluctuations in ITO prices in the past decade and ITO is known to account more than 50% of the total cost of OPV devices. Thus, it is believed that development of solution-processable alternative materials is of great importance in reducing the cost of OPVs. Numerous materials, including silver nanowires, carbon nanotubes, graphene and conducting polymers, have been offered as replacements for ITO. This article reviews recent progress on fabrication of TCE via solution based coating techniques of silver nanowires (Ag NWs). In addition, performance of the Ag NWs based TCE in OPVs is summarized. Finally, we explore the future outlook for Ag NWs based TCE at the end of the review.     

Photochemically initiated oxidative carbon-carbon bond-cleavage reactivity in chlorodiketonate Ni(II) complexes

Three mononuclear Ni(II) complexes containing a 2-chloro-1,3-diketonate ligand and supported by the 6-Ph(2)TPA chelate, as well as analogues that lack the 2-chloro substituent on the β-diketonate ligand, have been prepared and characterized. Upon irradiation at 350 nm under aerobic conditions, complexes containing the 2-chloro-substituted ligands undergo reactions to generate products resulting from oxidative cleavage, α-cleavage, and radical-derived reactions involving the 2-chloro-1,3-diketonate ligand. Mechanistic studies suggest that the oxidative cleavage reactivity, which leads to the production of carboxylic acids, is a result of the formation of superoxide, which occurs through reaction of reduced nickel complexes with O(2). The presence of the 2-chloro substituent was found to be a prerequisite for oxidative carbon-carbon bond-cleavage reactivity, as complexes lacking this functional group did not undergo these reactions following prolonged irradiation. The approach toward investigating the oxidative reactivity of metal β-diketonate species outlined herein has yielded results of relevance to the proposed mechanistic pathways of metalloenzyme-catalyzed β-diketonate oxidative cleavage reactions.     

Mann iterative process for pseudocontractive mappings

Let K be a nonempty, closed and convex subset of a real Banach space E. Let T:K→K be a strictly pseudocontractive map. For a fixed x ₀∈K, define a sequence {x _n } by x _n+1=(1?α _n )x _n +α _n Tx _n , where {α _n } is a real sequence defined in [0,1] satisfying the following conditions (i) $\sum_{n=0}^{\infty }\alpha _{n}=\infty $ , (ii) lim? _n→∞ α _n =0. Then lim?inf? _n→∞‖x _n ?Tx _n ‖=0. If, in addition, T is demicompact, then {x _n } converges strongly to some fixed point of T. Remark 8 is important.     

Novel method for laser focal point positioning on the cover slip for TPP-based microfabrication and detection of the cured structure under optical microscope

Detection of a single cured structure in two-photon photopolymerization (TPP) based microstructure fabrication requires the laser focal spot to be exactly positioned on the cover slip. This is due to the fact that if the laser focal position is not exactly on the cover slip, the structure may not stick to the cover slip and flow away with the liquid during the washing and developing stages. In this paper, we report a scheme of laser spot positioning for the implementation of TPP process and the detection of a single cured microstructure under an optical microscope. For this, a novel yet very simple approach is devised and an uncomplicated procedure is developed. Experimental results are also included to prove the worthiness of the devised method.     

Reversible carboxylation of N-heterocyclic carbenes

Spectroscopic analysis, thermogravimetric analysis, and crossover experiments performed on a series of imidazolium carboxylates revealed carboxylation was reversible with N-aryl substituted adducts.     

Formulation of a freeze-dried kit for 188Re-MAG3 and its quality control

The synthesis of ¹⁸⁸Re-MAG₃ is described using ¹⁸⁸Re, which was obtained from the alumina based ¹⁸⁸W/¹⁸⁸Re generator. Dependence of the radiolabeling yields of ¹⁸⁸Re-MAG₃ on reducing agent concentration, Bz-MAG₃ concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of ¹⁸⁸Re-MAG₃ was 98%. TLC and HPLC techniques were employed to monitor the different species formed. Biodistribution study of ¹⁸⁸Re-MAG₃ was carried out in rats and compared with behavior of ^99mTc-MAG₃.     

Reactions of SF6 with organotitanium and organozirconium complexes: the "inert" SF6 as a reactive fluorinating agent

The normally remarkably inert SF6 has been found to be quite reactive toward low valent organometallic compounds, under conditions in which usually powerful fluorinating agents may be less reactive. Reaction of SF6 with Ti[1,3-C5H3(t-Bu)2](6,6-dmch)(PMe3), for example, leads to {Ti[1,3-C5H3(t-Bu)2]F2}4 (dmch = dimethylcyclohexadienyl), whose structure is based on a cube of fluoride ions with the ligated titanium centers situated above four coplanar face centers.     

Mobility–diffusivity relationship for heavily doped organic semiconductors

The relationship between the diffusivity D _n and the mobility μ _n of chemically doped organic n-type semiconductors exhibiting a disordered band structure is presented. These semiconductors have a Gaussian-type density of states. So, calculations have been performed to elucidate the dependence of D _n /μ _n on the various parameters of this Gaussian density of states. Y. Roichman and N. Tessler (Appl. Phys. Lett. 80:1948, 2002), and subsequently Peng et al. (Appl. Phys. A 86:225, 2007), conducted numerical simulations to study this diffusivity–mobility relationship in organic semiconductors. However, almost all other previous studies of the diffusivity–mobility relationship for inorganic semiconductors are based on Fermi–Dirac integrals. An analytical formulation has therefore been developed for the diffusivity/mobility relationship for organic semiconductors based on Fermi–Dirac integrals. The D _n /μ _n relationship is general enough to be applicable to both non-degenerate and degenerate organic semiconductors. It may be an important tool to study electrical transport in these semiconductors.