NOVELTY - An organic dye comprises selenophen, 3,4-ethyldithiothiophene, or their derivatives as conjugate units.    USE - An organic dye for dye-sensitized solar cell (claimed).    ADVANTAGE - The organic dyes are synthesized with a higher overall yield from 60-70% without using expensive metal ruthenium as a material and glucosan as a purifying agent. The organic dye exhibits excellent properties, for instance, spectrum absorption with a peak value furthest exceeding 580 nm, a molar extinction coefficient exceeding 36x 103 M-1 cm-1, which are both superior to ruthenium dyes and most of the organic dyes. The organic dye absorbs solar light in wider range. The dye provides dye-sensitized solar cell having incident photon-to-current conversion efficiency (IPCE) up to 94% and photoelectric conversion efficiency furthest above 7.0%.    DETAILED DESCRIPTION - An organic dye comprises selenophen, 3,4-ethyldithiothiophene, or their derivatives as conjugate units. The organic dye is of formula (I).    A=O, S Se or N-R16;    R0=selenophen, 3,4-ethyldithiothiophene, or their derivatives;    R1, R2=(heterocyclic) aromatic hydrocarbon, derivatives of heterocyclic aromatic hydrocarbon, or preferably groups of formulae (2)-(6);    R3=H+, NH4+, an alkali metal cation, an alkali earth metal cation, other metal cation, or alkyl ammonium ion;    R4-R15=H, OH, alkane, cycloalkyl, alkoxy, aryloxy, aralkyl, alkylthio, haloalkyl or halo;    R16=H, alkane, cycloalkyl or aralkyl;and    m=1-10.    An INDEPENDENT CLAIM is included for dye-sensitized solar cell prepared from the organic dye comprising conductive layer (2), an optical absorption layer (3), an electrolyte layer (6) and a counter electrode (7) sequentially connected between two transparent substrate layers (1). The optical absorption layer comprises semiconductor nanoparticle layer connected with the conductive layer and a dye layer connected with the electrolyte layer. The transparent substrate layer is a glass or plastic substrate. The plastic is ethylene terephthalate, poly(ethylene glycol) naphthalate, polycarbonate, polypropylene, polyimide, triacetyl fiber or polyethersulfone. The conductive layer is indium tin oxide, fluorine tin oxide, zinc oxide-gallium oxide, zinc oxide-alumina, tin-based oxide, antimony tin oxide, or zinc oxide. The semiconductor nanoparticle in the semiconductor nanoparticle layer is silicon, titanium dioxide, tin dioxide, zinc oxide, tungsten oxide, niobium oxide, or titanium strontium oxide with an average particle diameter of less than or equal to 50 nm. The dye is the organic dye. The electrolyte layer is iodine or iodized salt electrolyte, ionic liquid, organic hole transport material, or inorganic hole transport material. The ionic liquid comprises anions and cations. The anions are iodide, bromide, chloride, dicyanamide, (trifluoromethanesulfonyl)imide, hexafluorophosphide, tetrafluroboride, trifluoroacetate, chlorate, trifluoromethyl trifluoroboride, trifluoromethanesulfonate, trifluoromethyl difluorosulfonate, methyl hydrosulfite, bistrifluoromethylsulfonylimide, biphenyl disulfonylamide, (trifluoromethanesulfonyl)imide carbide, trifluorosulfonate carbide, ethyl sulfite, trifluoromethyl carboxylate, trifluoromethyl difluoromethyl carboxylate, methyl carboxylate, triethyl phosphotrifluoride, tris(trifluoromethyl)phosphotrifluoride, ethyl-bis(trifluoromethyl)phosphotrifluoride, tris(trifluoroethyl)phosphotrifluoride, pentalfluoro bistrifluoromethylphosphotrifluoride, tris(trifluoromethyl)phosphotrifluoride, triphenyl phosphotrifluoride, tripropyl phosphotrifluoride, tributyl phosphotrifluoride, diphenyl phosphotetrafluoride, diphenyl phosphate, diphenyl phosphite, diphosphobenzyl tetrafluoride, di(trifluoromethyl)phospho tetrafluoride, di(trifluoromethyl) phosphate, dimethyl phosphate, butyl phosphate, trifluoromethyl phosphite, dimethyl phosphite, di(methyl dioxophosphorane), dimethyl phosphite, di(tetrafluoroethyl) difluoroboride, ethyl trifluoroboride, di(trifluoromethyl)difluoroboride, pentafluoroethyl boride, cyanotrifluoroboride, dicyanodifluoroboride, tetra(trifluoromethy)boride, tetraoxymethyl boride, dimethyl ethyl boride, aluminum tetrachloride, di(hexafluorosilicide), di(trifluoromethyl)nitride, bis(ethane-1,2-diolato) boride, bis(methanoxymethano)boride, or bis(oxyethyl)boride. The organic hole transport material is 2,2',7,7'-tetra-bi(di-p-methoxyphenylamine)-9,9'-spirobifluorene or other organic P-type semiconductor. The counter electrode is platinum, gold, nickel, copper, silver, indium, ruthenium, palladium, rhodium, iridium, osmium, carbon, or conductive polymer. The conductive polymer is polyphenylamine, polypyrrole, polythiophene, poly(p-phenylene vinylene), or polyether.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross sectional view of the dye-sensitized solar cell.    Transparent substrate layer (1)    Conductive layer (2)    Optical absorption layer (3)    Electrolyte layer (6)    Counter electrode (7)