Narrow-Band Organic Photodiodes for High-Resolution Imaging.

There are growing opportunities and demands for image sensors that produce higher-resolution images, even in low-light conditions. Increasing the light input areas through 3D architecture within the same pixel size can be an effective solution to address this issue. Organic photodiodes (OPDs) that possess wavelength selectivity can allow for advancements in this regard. Here, we report on novel push-pull D-π-A dyes specially designed for Gaussian-shaped, narrow-band absorption and the high photoelectric conversion. These p-type organic dyes work both as a color filter and as a source of photocurrents with linear and fast light responses, high sensitivity, and excellent stability, when combined with C60 to form bulk heterojunctions (BHJs). The effectiveness of the OPD composed of the active color filter was demonstrated by obtaining a full-color image using a camera that contained an organic/Si hybrid complementary metal-oxide-semiconductor (CMOS) color image sensor.

Preparation and reactivity of a tetranuclear Fe(II) core in the metallothionein α-domain.

Metallothioneins (MTs) are small cysteine-rich proteins which exhibit high affinities for various metal ions and play roles in storage of essential metals and detoxification of toxic metals. Studies on the redox properties of MTs have been quite limited. Recently, we focused on the α-domain of MT (MTα) as a protein matrix and incorporated a tetranuclear metal cluster as a reductant. UV-visible, CD and MS data indicate the formation of the stable tetranuclear metal-cysteine cluster in the MTα matrix with Fe(II)(4)-MTα and Co(II)(4)-MTα species existing in water. Furthermore, the Fe(II)(4)-MTα species was found to promote the reduction of met-myoglobin and azobenzene derivatives under mild conditions. Particularly, the stoichiometric reduction of methyl red with Fe(II)(4)-MTα (1:1) was found to proceed with a conversion of 98% over a period of 6h at 25°C. This indicates that all of the four Fe(II) cores contribute to the reduction. In this paper, we describe the preparation and reactivity of the tetranuclear iron cluster in the protein matrix.