Atsushi Wakamiya 교수

This work provides an efficient way to facilitate both electron and hole extraction in the designated interfaces of perovskite solar cells. A record power conversion efficiency of 23.6% for mixed Sn–Pb perovskite solar cell devices is realized.

Seeing the light: Tuning the electron-donating ability of the π-conjugated framework of bithiophene has resulted in intense solid-state emissions with maxima ranging over a wide visible region (see picture). Even a deep-red fluorescence with a large Stokes shift close to 200 nm, arising from the intramolecular charge-transfer (CT) transition from the twisted bithiophene π framework to the boron center, can be obtained.

Stacking the deck: Incorporation of boryl groups into the thienylthiazole system fixes the π-conjugated framework in a planar fashion by intramolecular B–N coordination. The dimer of boryl-substituted thienylthiazole forms a unique packing structure with offset face-to-face π stacking (see picture; B orange, N blue, S yellow, C turquoise) and films of it show high electron mobility. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/200

Lead halide complexes formed during the fabrication of perovskite (CH3NH3PbI3)-based solar cells were examined by single-crystal X-ray diffraction analysis. Based on the observed results, the fabrication protocol using a sequential deposition method was optimized to reproducibly provide highly efficient solar cells with power conversion efficiencies of more than 10%.

Abstract Boron, a group 13 element, has several characteristic structural and electronic features: 1) trivalent boron compounds usually adopt a trigonal planar geometry; 2) due to the presence of a vacant p-orbital, effective orbital interaction with π-conjugated compounds is possible; 3) the presence of a vacant p-orbital is furthermore responsible for high Lewis acidity; 4) the boryl group acts as a π-electron-accepting group particularly in the excited state. The consequent exploitation of th

Two simple methods to improve tin halide perovskite film structure are introduced, aimed at increasing the power conversion efficiency of lead free perovskite solar cells. First, a hot antisolvent treatment (HAT) was found to increase the film coverage and prevent electrical shunting in the photovoltaic device. Second, it was discovered that annealing under a low partial pressure of dimethyl sulfoxide vapor increased the average crystallite size. The topographical and electrical qualities of the

Abstract Dimers of partially oxygen‐bridged triarylamines were designed and synthesized as hole‐transporting materials. X‐ray structural analyses revealed that these compounds form on‐top π‐stacking aggregates in the crystalline state. TRMC measurements showed that high levels of anisotropic charge transport were induced in the direction of the π‐stacking. Surprisingly, even in vacuum‐deposited amorphous films, these compounds retained some of the face‐on π‐stacking, thus facilitating an out‐of‐

Farbenfroh: Durch Einstellen der Elektronendonoreigenschaften des π-konjugierten Bithiophen-Gerüsts wurden intensiv emittierende Festkörper erhalten, deren Maxima einen großen Teil des sichtbaren Spektrums abdecken (siehe Bild). Eine tiefrote Fluoreszenz mit großer Stokes-Verschiebung um 200 nm resultiert aus einem intramolekularen Charge-Transfer(CT)-Übergang vom verdrillten Bithiophen auf das Borzentrum.

With the aid of borylation and oxidative coupling reactions, six new polycyclic aromatic hydrocarbons (PAHs) doped by nitrogen-boron-nitrogen (NBN) units were achieved. The structure-optoelectronic property relationship for this group of compounds was examined. All six compounds are fluorescent with contrasting emission colors and quantum yields.

Interfaces in thin-film photovoltaics play a pivotal role in determining device efficiency and longevity. In this work, the top surface treatment of mixed tin-lead (≈1.26 eV) halide perovskite films for p-i-n solar cells is studied. Charge extraction is promoted by treating the perovskite surface with piperazine. This compound reacts with the organic cations at the perovskite surface, modifying the surface structure and tuning the interfacial energy level alignment. In addition, the combined tre