다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Following pioneering work, solution-processable organic-inorganic hybrid perovskites-such as CH3NH3PbX3 (X = Cl, Br, I)-have attracted attention as light-harvesting materials for mesoscopic solar cells. So far, the perovskite pigment has been deposited in a single step onto mesoporous metal oxide films using a mixture of PbX2 and CH3NH3X in a common solvent. However, the uncontrolled precipitation of the perovskite produces large morphological variations, resulting in a wide spread of photovoltaic performance in the resulting devices, which hampers the prospects for practical applications. Here we describe a sequential deposition method for the formation of the perovskite pigment within the porous metal oxide film. PbI2 is first introduced from solution into a nanoporous titanium dioxide film and subsequently transformed into the perovskite by exposing it to a solution of CH3NH3I. We find that the conversion occurs within the nanoporous host as soon as the two components come into contact, permitting much better control over the perovskite morphology than is possible with the previously employed route. Using this technique for the fabrication of solid-state mesoscopic solar cells greatly increases the reproducibility of their performance and allows us to achieve a power conversion efficiency of approximately 15 per cent (measured under standard AM1.5G test conditions on solar zenith angle, solar light intensity and cell temperature). This two-step method should provide new opportunities for the fabrication of solution-processed photovoltaic cells with unprecedented power conversion efficiencies and high stability equal to or even greater than those of today's best thin-film photovoltaic devices.

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Sequential deposition as a route to high-performance perovskite-sensitized solar cells

/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

1. INTRODUCTION Among the classes of highly porous materials, metalÀorganic frameworks (MOFs) are unparalleled in their degree of tunability and structural diversity as well as their range of chemical and physical properties. MOFs are extended crystalline structures wherein metal cations or clusters of cations (\" nodes \") are connected by multitopic organic \" strut \" or \" linker \" ions or molecules. The variety of metal ions, organic linkers, and structural motifs affords an essentially infinite number of possible combinations. 1 Furthermore, the possibility for postsynthetic modification adds an additional dimension to the synthetic variability. 2 Coupled with the growing library of experimentally determined structures, the potential to computationally predict, with good accuracy, affinities of guests for host frameworks points to the prospect of routinely predesigning frameworks to deliver desired properties. 3,4 MOFs are often compared to zeolites for their large internal surface areas, extensive porosity, and high degree of crystallinity. Correspondingly, MOFs and zeolites have been utilized for many of the same applications

Metal–Organic Framework Materials as Chemical Sensors

Historical perspective on: UPS of buckminsterfullerene and other large clusters of carbon [Volume 139, Issues 3–4, 28 August 1987, Pages 233–238]

The crystalline-amorphous (c-a) structure is emerging as a promising design of oxygen evolution electrocatalysts. However, homogenous compositions and excellent stability are hindering further industrial applications. Only by using metal nitrates and methanol solvent, we provide an effective steam-driven strategy to directly fabricate c-a electrocatalysts. The division of methanol molecules establishes an experimental approach to analyze the targeted transformation from crystalline to c-a phase for monometallic nickel hydroxy-nitrates. Following, this design is successfully extended to the bimetallic NiFe layered double hydroxide (NiFe-LDH). The presence of Fe 3+ not only effectively promotes electrochemical activity but also enhances adhesion to the nickel foam, conjuring up an ultra-active and ultra-stable NiFe A-S @NF electrocatalyst with an overpotential of 205 mV at 10 mA cm -2 and excellent 200 h stability at 500-1000 mA cm -2 . In light of the above findings and preliminary scale-up experiment, this approach offers both fundamental and practical guidelines for other non-noble-metal-based electrocatalysts. • Steam-driven strategy is feasible to obtain crystalline-amorphous structures • Spatially interrupted growth caused by steam determines the conversion process • Superior stability can be attributed to the enhanced adhesion and c–a structure 

Steam-driven crystalline-amorphous coupling design of homogenous metal hydroxides for oxygen evolution reaction

LnVO4 (Ln=Ce and Nd) nanocrystals (NCs) with square plate, H-shaped, and rod-like morphologies have been synthesized in nanosized reverse micelle reactors, via a facile solvo/hydrothermal strategy. We have also identified a unique upconverted avalanche luminescence properly pertaining to the NCs, and undertaken a systematic mechanistic study.

Monodisperse nanocrystals of LnV0 4 (Ln = Ce, Nd): Controlled synthesis and upconverted avalanche luminescence

Nanoscale optics can be applied to various fields, e.g., sensor, energy harvesting, and communication [1]. A fundamental understanding of their properties is necessary to fulfill the potential of nano optics. However, the relatively low spatial resolution of traditional optical measurement methods, e.g., Raman spectroscopy and infrared spectroscopy, set an obstacle to study the photonic properties for nanoscale optical structures. By the Weizsäcker-Williams approximation [2–4], the electromagnetic field generated by high-speed charged particles (e.g., electron in transmission electron microscope (TEM)) can be approximated as virtual quanta, e.g. virtual photons. In other words, in TEM, electrons can be used as a light source with a higher spatial resolution. Another unmatched advantage of using TEM to detect optic properties is that it can simultaneously excite and detect energy loss process in a large range of energy, from infrared [5] to ultraviolet [6], through electron energy-loss spectroscopy (EELS) in a scanning TEM (STEM). In sub-micron-sized dielectric particles e.g., CeO2 (ceria), light can be trapped in the form of photonic modes, providing opportunities for energy harvesting and information transfer. Here, we applied monochromated STEM EELS to study the photonic modes in a ceria cube.

Revealing Photonic Properties with High Spatial Resolution: An EELS Study on Ceria Nanocubes

Laser induced reaction of Ca+- tertbutylamine complex was studied by reflection time of flight spectrum (RTOF). Different photodissociation spectra, the action spectrum as function of laser wavelength, and ratio curve of different channels were obtained. Two channels were found, one was Ca+ cation separation channel, the other one was reactive channel for product Ca+NH2. Product Ca+ was dominant in the whole region studied and the only one in the region 530 similar to 595 nm. The action spectrum shows pronounced structureless peaks, which are relevant to the transition of complex. The dynamics of the reaction was discussed at the end.

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Shihe Yang

Papers

Historical perspective on: UPS of buckminsterfullerene and other large clusters of carbon [Volume 139, Issues 3–4, 28 August 1987, Pages 233–238]

Steam-driven crystalline-amorphous coupling design of homogenous metal hydroxides for oxygen evolution reaction

Monodisperse nanocrystals of LnV0 4 (Ln = Ce, Nd): Controlled synthesis and upconverted avalanche luminescence

Revealing Photonic Properties with High Spatial Resolution: An EELS Study on Ceria Nanocubes

Photo-induced intra-complex reactions in Ca+-NH2C(CH3)(3)