The present invention further improves the measurement accuracy of the viscosity of an ink composition. An ink composition for forming a functional layer of an organic photoelectric conversion element, wherein an electron spin concentration per 1 L of volume of the ink composition is 250×10.sup.16 or less. The ink composition may be an ink composition containing a solvent and a p-type semiconductor material. The ink composition may be an ink composition in which the p-type semiconductor material contains a polymer compound having an electron spin concentration per 1 g of weight of 70×10.sup.16 or less. The ink composition may be an ink composition in which the solvent contains one or more types of organic solvents and the p-type semiconductor material contains a π-conjugated polymer compound containing a donor constitutional unit and an acceptor constitutional unit.

The photosensitive composition according to the present invention is a photosensitive composition including a semiconductor particle (A), a photopolymerizable compound (C) and a photopolymerization initiator (D), in which the photosensitive composition satisfies any one or more of the following (a) to (c): (a) the photosensitive composition further includes a stabilizer (E), and a content of the stabilizer (E) is 8% by mass or more based on the total amount of the photosensitive composition; (b) the photopolymerizable compound (C) includes a (meth)acrylate compound (C1) having a molecular weight of 180 or less; and (c) the photopolymerizable compound (C) includes a compound (C2) having a vinyl ether group and a (meth)acryloyl group in the same molecule.

The photosensitive composition according to the present invention is a photosensitive composition including a semiconductor particle (A), a photopolymerizable compound (C) and a photopolymerization initiator (D), in which the photosensitive composition satisfies any one or more of the following (a) to (c): (a) the photosensitive composition further includes a stabilizer (E), and a content of the stabilizer (E) is 8% by mass or more based on the total amount of the photosensitive composition; (b) the photopolymerizable compound (C) includes a (meth)acrylate compound (C1) having a molecular weight of 180 or less; and (c) the photopolymerizable compound (C) includes a compound (C2) having a vinyl ether group and a (meth)acryloyl group in the same molecule.

An active energy ray polymerization initiator has a structure of Chemical Formula (1) or (2),

##STR00001## L.sub.1 represents Chemical Formula (I), L.sub.2 represents Chemical Formula (II), one of L.sub.3 and L.sub.4 and one of L.sub.5 and L.sub.6 represent the same group as L.sub.1, the rest of L.sub.3 and L.sub.4 and one of L.sub.5 and L.sub.6 represent the same group as L.sub.2, Link 2 represents a single bond, —O—, —CO—, —SO.sub.2—, —C(CF.sub.3).sub.2—, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an aromatic group having 6 to 15 carbon atoms,

##STR00002## Z represents a tertiary amine.

##STR00003## R represents a hydrocarbon group having one to three carbon atoms or methoxy group, n represents 0 or an integer of from 1 to 3, Link 1 represents —(CH.sub.2).sub.x—(OC.sub.2H.sub.4).sub.y—, where x represents an integer of from 2 to 12 and y represents 0 or an integer of from 1 to 11.

One aspect of this invention relates to hexagonal boron nitride (hBN) ionogel inks using exfoliated hBN nanoplatelets as the solid matrix. The hBN nanoplatelets are produced from bulk hBN powders by liquid-phase exfoliation, allowing printable hBN ionogel inks to be formulated following the addition of an imidazolium ionic liquid and ethyl lactate. The resulting inks are reliably printed with variable patterns and controllable thicknesses by aerosol jet printing, resulting in hBN ionogels that possess high room-temperature ionic conductivities and storage moduli of >3 mS cm-1 and >1 MPa, respectively. By integrating the hBN ionogel with printed semiconductors and electrical contacts, fully-printed thin-film transistors with operating voltages below 1 V are demonstrated on polyimide films. These devices exhibit desirable electrical performance and robust mechanical tolerance against repeated bending cycles, thus confirming the suitability of hBN ionogels for printed and flexible electronics.

The present disclosure describes a new resin which can be fabricated into conductive and bioactive microstructures via two-photon polymerization. The direct incorporation of conductive poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) and/or multi-walled carbon nanotubes (MWCNTs) in a poly(ethylene glycol) diacrylate (PEGDA)-based blend remarkably enhances the electrical conductivity of microstructures over 10 orders of magnitude. Including biomaterials in the resin can promote cellular adhesion and create functional biosensors made of hybrid non-conductive and conductive structures for sensitive detection. Applications include development cost effective microelectronics in a broad range of biomedical research, electronics and sensors.

An ink jet recording head that includes a substrate having an ejection orifice for ejecting a liquid and a member provided with a recessed portion for accommodating the substrate, the head including a gap formed between a wall of the recessed portion of the member and the substrate, and a sealing material that seals the gap, in which the sealing material contains a cured product of a composition containing at least a hydrogenated bisphenol A type epoxy resin, a solid basic compound, and polythiol.

An ink jet recording head that includes a substrate having an ejection orifice for ejecting a liquid and a member provided with a recessed portion for accommodating the substrate, the head including a gap formed between a wall of the recessed portion of the member and the substrate, and a sealing material that seals the gap, in which the sealing material contains a cured product of a composition containing at least a hydrogenated bisphenol A type epoxy resin, a solid basic compound, and polythiol.

A method for generating reactive species in a medium in which light irradiates the medium including a nanoparticle. A photoinitiator composed of semiconductor nanoparticles for photo-polymerization and 2D and 3D printing.

A method for generating reactive species in a medium in which light irradiates the medium including a nanoparticle. A photoinitiator composed of semiconductor nanoparticles for photo-polymerization and 2D and 3D printing.