Kyoto University · 工学
Nakamura教授の研究室では、次世代太陽電池として注目されるペロブスカイト半導体の材料設計とプロセス開発に注力しています。特に、鉛フリーなスズペロブスカイト太陽電池の効率向上を目的とし、スズ(II)の酸化を抑制する新規な還元剤や高純度前駆体の開発を進めています。また、透明な電子輸送材料や近赤外吸収材料の設計・合成を通じて、有機・ペロブスカイト太陽電池の高効率化に貢献しています。
Figures are computed from collected data and may differ slightly.
The toxicity of lead perovskite hampers the commercialization of perovskite-based photovoltaics. While tin perovskite is a promising alternative, the facile oxidation of tin(II) to tin(IV) causes a high density of defects, resulting in lower solar cell efficiencies. Here, we show that tin(0) nanoparticles in the precursor solution can scavenge tin(IV) impurities, and demonstrate that this treatment leads to effectively tin(IV)-free perovskite films with strong photoluminescence and prolonged dec
The commercial development of perovskite-based photovoltaics is hindered by the toxicity of lead perovskite. Although tin perovskite is a promising alternative, the power conversion efficiency of tin perovskite solar cells has not reached levels comparable to the lead-based devices. Several factors, including the facile oxidation of tin(II) to tin(IV) and difficulties in controlling the morphology of the perovskite layers, are responsible for the lower efficiency. By closely integrating the deve
The potential of naphthalene-1,8:4,5-tetracarboxylic diimide (NDI-H) as a transparent electron-transporting material was examined. A soluble precursor was designed and synthesized having two tert-butoxycarbonyl solubilizing substituents at the imide moieties. This precursor molecule, NDI-Boc, is converted to the hydrogen-substituted NDI-H by heating the spin-coated precursor films. The molecular orientation during the thermal conversion of NDI-Boc to NDI-H was examined using two-dimensional graz
Abstract Metal halide perovskite semiconductors are excellent materials for next-generation solar cells. As a result of research and development all over the world, the photoelectric conversion efficiency for single-cell devices has rapidly improved to over 26% (as of July 2023), while the record efficiency for silicon-on-perovskite tandem devices currently stands at 33.7% (reported in May 2023). Materials chemistry has made many important contributions toward these remarkable results. In this a
Benzodipyrrole-based donor-acceptor boron complexes were designed and synthesized as near-infrared-absorbing materials. The electron-rich organic framework combined with the Lewis acidic boron co-ordination enabled us to tune the LUMO energy level and the HOMO-LUMO gap (i.e.,the absorption wavelength) by changing the organic acceptor units, the number of boron atoms, and the substituents on the boron atoms.
Two p-type semiconducting donor-acceptor polymers were designed and synthesized for use in organic solar cells. The polymers combine a benzodithiophene (BDT) donor and a thiazole-fused benzothiadiazole (TzBT) acceptor. Two TzBT acceptor units are compared, one with an alkylthio group (P1) and the other with a more strongly electron-withdrawing alkylsulfonyl group (P2) at the fused thiazole ring. The strongly electron-accepting nature of the TzBT unit lowers the lowest unoccupied molecular orbita
The wide band gaps of bromide-containing tin perovskites, ASnI3–xBrx, make them attractive materials for use as the top-layer absorber in tandem solar cells, as well as in single-junction solar cells for indoor applications. In the present work, a series of ASnI3–xBrx films was systematically fabricated by varying the A-site (FA+, MA+, and Cs+) and X-site (I– and Br–) ions. The use of a solvent-coordinated SnBr2 complex as a high-purity source of bromide combined with Sn(IV) scavenging treatment
A star-shaped molecule featuring three phthalimide units attached to a triazine core was designed as an electron-transport material. Solution processing was achieved by preparing a precursor molecule bearing tert-butoxycarbonyl (Boc) substituents, which are afterwards removed by annealing. The annealed film is transparent to visible light, with an absorption edge of 339 nm. Two-dimensional grazing incidence X-ray diffraction (2D-GIXD) and p-polarized multiple-angle incidence resolution spectrome
Although fullerene bisadducts are promising electron-transporting materials for tin halide perovskite solar cells, they are generally synthesized as a mixture of isomeric products that require a complicated separation process. Here, we introduce a phenylene-bridged bis(pyrrolidino)fullerene, Bis-PC, which forms only a single isomer due to geometrical restriction. When used in a tin perovskite solar cell with a PEA<sub>0.15</sub>FA<sub>0.85</sub>SnI<sub>3</sub> (PEA: phenylethylammonium and FA: f
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