Organic dye presenting the following formula: in which - the radicals Ar 1 and Ar 2, identical or different, represent an aryl group optionally substituted; - the radicals R 1 to R 4, identical or different, represent a hydrogen, a halogen, a cyano group (-CN), a nitro group (-NO 2), an alkyl group optionally substituted, an aryl group optionally substituted, an alkylaryl group optionally substituted or an arylalkyl group optionally substituted; the radicals R 1 and R 2 may form with the carbons to which they are attached an aromatic or heteroaromatic ring eventually substituted and the radicals R 3 and R 4 may form with the carbons to which they are attached an aromatic or heteroaromatic ring eventually substituted; in which either the radical Ar 1 and/or the radical Ar 2 is/are substituted by a segment -eD and at least one element selected in the group consisting of the radical R 1, the radical R 2, the radical R 3, the radical R 4, the aromatic or heteroaromatic ring formed by the radicals R 1 and R 2 with the carbons to which they are attached and the aromatic or heteroaromatic ring formed by the radicals R 3 and R 4 with the carbons to which they are attached is substituted by a segment -L-A; or the radical Ar 1 and/or the radical Ar 2 is/are substituted by a segment -L-A and at least one element selected in the group consisting of the radical R 1, the radical R 2, the radical R 3, the radical R 4, the aromatic or heteroaromatic ring formed by the radicals R 1 and R 2 with the carbons to which they are attached and the aromatic or heteroaromatic ring formed by the radicals R 3 and R 4 with the carbons to which they are attached is substituted by a segment -eD; with - -eD representing an electron donor segment, - -L- representing a covalent bond or a spacer segment and particularly a pi-conjugated spacer segment, and - -A representing an electron attractor segment able to form a covalent bond with a semi-conductor, wherein said segment -eD is an amino group of (Z 1)(Z 2)N- type, with Z 1 and Z 2, identical or different, representing an alkyl group optionally substituted or an aryl group optionally substituted and wherein said segment -A is a carboxylic acid group, a cyanoacrylic acid group, a phosphonic group, a dithiocarboic group or a group corresponding to any of the following formula: - the radicals Ar 1 and Ar 2, identical or different, represent an aryl group optionally substituted; - the radicals R 1 to R 4, identical or different, represent a hydrogen, a halogen, a cyano group (-CN), a nitro group (-NO 2), an alkyl group optionally substituted, an aryl group optionally substituted, an alkylaryl group optionally substituted or an arylalkyl group optionally substituted; the radicals R 1 and R 2 may form with the carbons to which they are attached an aromatic or heteroaromatic ring eventually substituted and the radicals R 3 and R 4 may form with the carbons to which they are attached an aromatic or heteroaromatic ring eventually substituted; in which either the radical Ar 1 and/or the radical Ar 2 is/are substituted by a segment -eD and at least one element selected in the group consisting of the radical R 1, the radical R 2, the radical R 3, the radical R 4, the aromatic or heteroaromatic ring formed by the radicals R 1 and R 2 with the carbons to which they are attached and the aromatic or heteroaromatic ring formed by the radicals R 3 and R 4 with the carbons to which they are attached is substituted by a segment -L-A; or the radical Ar 1 and/or the radical Ar 2 is/are substituted by a segment -L-A and at least one element selected in the group consisting of the radical R 1, the radical R 2, the radical R 3, the radical R 4, the aromatic or heteroaromatic ring formed by the radicals R 1 and R 2 with the carbons to which they are attached and the aromatic or heteroaromatic ring formed by the radicals R 3 and R 4 with the carbons to which they are attached is substituted by a segment -eD; with - -eD representing an electron donor segment, - -L- representing a covalent bond or a spacer segment and particularly a pi-conjugated spacer segment, and - -A representing an electron attractor segment able to form a covalent bond with a semi-conductor, - -eD representing an electron donor segment, - -L- representing a covalent bond or a spacer segment and particularly a pi-conjugated spacer segment, and - -A representing an electron attractor segment able to form a covalent bond with a semi-conductor, wherein said segment -eD is an amino group of (Z 1)(Z 2)N- type, with Z 1 and Z 2, identical or different, representing an alkyl group optionally substituted or an aryl group optionally substituted and wherein said segment -A is a carboxylic acid group, a cyanoacrylic acid group, a phosphonic group, a dithiocarboic group or a group corresponding to any of the following formula: