There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

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Dye-Sensitized Solar Cells

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

Two new polydentate ligands, 1-(6-hydroxymethyl-2-pyridyl)-3-(2-pyridyl)-propane-1,3-dione (6) and 1,3-bis(6-hydroxymethyl-2-pyridyl)-propane-1, 3-dione (8), have been synthesized starting from 2,6 ...

Practical Synthesis of New β-Diketone-Connected Bipyridine and Its Conversion to Pyrazole-Centered Bipyridine Ligand.

Photochemical Hydrogen Production with Earth-Abundant Metal Complexes as Molecular Catalysts

Photochemical Hydrogen Production with Earth‐Abundant Metal Complexes as Molecular Catalysts

Identifying the Active Site of Water Oxidation Catalyst Based on Defective Fe-Doped Ni Oxyhydroxide

Design and Evaluation of a Compact Thermoelectric Generation System for Harvesting Low and Medium Temperature Geothermal Energy

The mol­ecule of the title compound, C24H16BrN3OS3, contains three approximately planar fragments, viz. an oxadiazole ring plus two adjacent thio­phene groups, and two phenothia­zine benzene rings, with largest deviations from the least-squares planes of 0.051 (3), 0.019 (4) and 0.014 (3) A, respectively. The phenothia­zine unit adopts a butterfly conformation, with a dihedral angle of 38.06 (15)° between the terminal benzene rings. The dihedral angle between the 2,5-bis­(thio­phen-2-yl)oxadiazole unit and the attached benzene ring is 15.35 (11)°. In the crystal, mol­ecules form stacks along the b-axis direction; neighboring mol­ecules within the stack are related by inversion centers, with shortest inter­centroid separations of 3.741 (2) and 3.767 (2) A.

https://journals.iucr.org/e/issues/2012/05/00/yk2050/yk2050.pdf

Licheng Sun

Papers

Practical Synthesis of New β-Diketone-Connected Bipyridine and Its Conversion to Pyrazole-Centered Bipyridine Ligand.

Photochemical Hydrogen Production with Earth‐Abundant Metal Complexes as Molecular Catalysts

Identifying the Active Site of Water Oxidation Catalyst Based on Defective Fe-Doped Ni Oxyhydroxide

Design and Evaluation of a Compact Thermoelectric Generation System for Harvesting Low and Medium Temperature Geothermal Energy

2-(5-Bromo-thio-phen-2-yl)-5-[5-(10-ethyl-phenothia-zin-3-yl)thio-phen-2-yl]-1,3,4-oxadiazole.