佐藤根 大士

Bicellar mixtures containing diacetylene molecules, such as diynoic acids, can be used as parent materials for functional membranes. A bicellar mixture consisting of a diynoic acid-10,12-tricosadiynoic acid (TCDA)-, a phospholipid-1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-, and a detergent-3-[(3-cholamidopropyl) dimethylammonio]-2-hydroxypropanesulfonate (CHAPSO)-was evaluated for its morphology and packing of TCDA molecules in its bicellar mixture. A TCDA/DMPC vesicle was prepared at different molar ratios, TCDA/DMPC = 2/8, 5/5, and 8/2; a TCDA/DMPC/CHAPSO bicellar mixture was prepared by mixing a CHAPSO solution with a TCDA/DMPC vesicle solution as a detergent at different composition ratios, x TCDA/DMPC = [TCDA/DMPC]/([TCDA/DMPC]+[CHAPSO]), of 1.0, 0.70, 0.50, and 0.30. A DMPC molecule formed a bilayer membrane structure and was used to suppress its precipitation. The packing density of the TCDA/DMPC/CHAPSO bicellar mixtures was increased by mixing a CHAPSO molecule in x TCDA/DMPC = 1.0 to 0.70 or 0.50. A TEM image of a TCDA/DMPC/CHAPSO bicellar mixture showed many discoidal assemblies at x TCDA/DMPC = 0.5 of TCDA/DMPC = 5/5. Polymerization of the TCDA molecules in the bicellar mixture by UV light suggested an ordered arrangement of TCDA. Polymerization at x TCDA/DMPC = 0.70 and 0.50 correlated with improved packing density.

To fabricate fully printed carbon-based multiporous-layered-electrode perovskite solar cells (MPLE-PSCs), a polymer binder thickener had to be added to the carbon paste for the conductive carbon electrode. The polymer binder thickener is a key material to control the dispersion of carbon particles, viscosity for screen printing, and thickness and porosity of carbon electrodes. In this work, the role and effect of polymer binder thickeners for high-temperature carbon porous electrodes on MPLE-PSCs have been investigated in detail. Several carbon pastes with/without polymer binder thickeners (4 types of ethyl cellulose and 2 types of hydroxypropyl cellulose, which have different viscosities) were compared. What we understand in this paper are (1) Aggregation and dispersion of carbon particles are controlled by the polymer binder thickener (ethyl cellulose and/or hydroxypropyl cellulose); (2) For the porous carbon electrodes, the polymer binder thickeners are carbonized during the sintering procedure at 400 °C and can be kept on the surface of carbon particles as the additional carbon surface skin, which improves the conductivity; (3) The polymer binder thickeners can help the formation of a fine mesoporous structure in the annealed carbon electrodes. Combinations of results between viscosity, thermal, and specific surface area analyses revealed the close relationship between device performance and printability, dispersibility, and porosity brought by the polymer binder thickeners. As a result, the addition of a 20 wt % polymer binder thickener improved the average power conversion efficiency (PCE) from 9.52 ± 2.04 to 10.86 ± 0.85%, achieving a champion PCE of 12.06%.

In this study, a novel reversible control method of particle dispersion/flocculation for nonaqueous solvent was developed. Titanium oxide was used as sample powder. Cyclopentasiloxane was used as solvent and Polyoxyethylene polyalkylsiloxane was used as a dispersant. First, a well-dispersed slurry was prepared by adding dispersant. After preparation, alcoholic amphiphilic molecule was added to the well-dispersed slurry to convert it from liquid to a gel-like consistency, which was caused by the hydrogen bond of dispersant on the surface of the particles. The resultant gel could easily be changed to liquid state by shaking. In addition, the slurry reverted back to gel state after a certain period of time. It was found that the relative permittivity and the additive amount of amphiphilic molecule has an influence on the strength of the gel.