We synthesized two bis-squaraine dyes consisting of benzo[1,2-b:5,4-b’]dipyrrole central components and indolenine-based semisquaraine or its dicyanovinylene analogue for application to electron donor materials for organic photodetectors with bulk heterojunction architecture. These dyes exhibited split electronic absorption bands attributed to intramolecular exciton coupling. The lower energy absorption band of the bis-squaraine dye with dicyanovinylene group was observed in the near-infrared region. In cyclic voltammograms of bis-squaraine dyes, broad redox waves were observed in oxidative scans, indicating that one-electron oxidized dyes have delocalized electronic states throughout two chromophores. The highest occupied molecular orbitals and the lowest unoccupied molecular orbitals of bis-squaraine dyes have suitable energy levels for electron donor materials toward the fullerene-based electron acceptor. A composite film comprised of a fullerene acceptor and a bis-squaraine dye showing near-infrared absorption exhibited a near infrared absorption with a maximum at ca. 780 nm, promising photo-induced electron transfer upon the irradiation of near infrared light. An organic photodetector with the composite film demonstrated a specific detectivity (D^＊) of 4.6×10¹¹ Jones under 750 nm illumination and 3.3×10¹¹ Jones under 800 nm illumination. This indicated that the bis-squaraine dye can work as the donor material in organic photodetectors responsive to near-infrared light.

Evaluation of jetting durability, which is an important performance property of inkjet ink, requires a large amount of ink and a long period of actual evaluation. Especially for thermal heads, a destructive test of the head has been mandatory for evaluation due to scorching to the heater. In contrast, as a method to predict lifetime without actual jetting, our newly developed zeta potential measurement method and a potential energy calculation protocol based on the classical DLVO (Derjaguin-Landau-Verwey-Overbeek) theory using the obtained zeta potential values are used. A method for predicting jetting durability was found.

With the rapid development of industry, large amounts of fossil fuels are consumed and greenhouse gases emitted are causing global warming. Thus, there is a need for clean energy that can replace fossil fuels. Among these, the utilization of hydrogen gas produced by water electrolysis is attracting attention. Therefore, we are developing new water splitting electrocatalysts from natural and circulating resources. In this paper, we will introduce various water splitting electrocatalysts that we have recently developed.

Organic solar cells (OSCs) have been expected as next generation power generation systems due to their distinctive features of low weight, flexibility, large-area processability, and color tunability. In this report, we will summarize novel OSCs based on poly(3-hexylthiophene) as a donor and our newly developed nonfullerene acceptors. To develop new agrivoltaics for plastic greenhouses, we also introduce green-light wavelength-selective OSCs, whose transmitted blue and red light can be effectively used to promote plant growth.

Cosmetics, perfumes, and toiletry products are intended to be applied or sprayed on the human body in order to keep the skin or hair healthy, and their effects on the human body should be mild. To develop one product, many kinds of academic fields such as dermatology, psychology, sensory engineering, color science, pharmacology, interface chemistry, analytical chemistry, microbiology, and process engineering are related. This review mainly focuses on basics of emulsification, which is essential for formulating the above products, and also explains the emulsification techniques used in the practical products.