Patent ID: 8470204

Claim:
An ink composition comprising phthalocyanine nanowires which contain phthalocyanine and a phthalocyanine derivative and an organic solvent as essential components, the ink composition being characterized in that: 1) the phthalocyanine is copper phthalocyanine, zinc phthalocyanine, or iron phthalocyanine; 2) the phthalocyanine derivative is represented by general formula (1), or (3) described below; and 3) the minor diameter of the phthalocyanine nanowires is 100 nm or less, and the ratio (length/minor diameter) of the length to the minor diameter is 10 or more; wherein in the formulae (1) and (2), X is selected from the group consisting of a copper atom, a zinc atom, a cobalt atom, a nickel atom, a tin atom, a lead atom, a magnesium atom, a silicon atom, and an iron atom, and Y 1 to Y 4 represent linking groups which bond a phthalocyanine skeleton to R 1 to R 4 , respectively; when Y 1 to Y 4 each represent a bond as the linking group, R 1 to R 4 each represent SO 3 H, CO 2 H, an alkyl group which may be substituted, an (oligo)aryl group which may be substituted, an (oligo)heteroaryl group which may be substituted, a phthalimide group which may be substituted, or a fullerene which may be substituted; when Y 1 to Y 4 are each a linking group represented by —(CH 2 ) n — wherein n represents an integer of 1 to 10, —CH≡CH—, —C≡C—, —O—, —NH—, —S—, —S(O)—, or —S(O) 2 —, R 1 to R 4 each represent an alkyl group which may be substituted, an (oligo)aryl group which may be substituted, an (oligo)heteroaryl group which may be substituted, a phthalimide group which may be substituted, or a fullerene which may be substituted; and a, b, c, and d each independently represent an integer of 0 to 2, but at least one of a, b, c, and d is 1; wherein in the formula (3), X is selected from the group consisting of a copper atom, a zinc atom, a cobalt atom, a nickel atom, a tin atom, a lead atom, a magnesium atom, a silicon atom, and an iron atom, Z is a group represented by a formula (a) or (b) described below, a, b, c, and d each independently represent an integer of 0 to 2 but at least one of a, b, c, and d is 1; wherein n is an integer of 4 to 100, each Q is independently a hydrogen atom or a methyl group, and Q′ is a noncyclic hydrocarbon group having 1 to 30 carbon atoms wherein m is an integer of 1 to 20, and R and R′ are each independently an alkyl group having 1 to 20 carbon atoms.