NOVELTY - A selenophen-containing bipyridyl ruthenium dye compound or its salt, is new.    USE - A selenophen-containing bipyridyl ruthenium dye compound or its salt, for dye layer of dye-sensitized solar cell (claimed), or for use as light absorption antenna ligand.    ADVANTAGE - The dye compound has simple manufacturing process, low cost and high production ratio; is easy to purify; and can be modified by molecule design. The solar cell has photoelectric transformation efficiency of more than 90% and cell efficiency of 9.5-10.1%.    DETAILED DESCRIPTION - A selenophen-containing bipyridyl ruthenium dye compound or its salt of formula (1), is new.    Y1, Y2=H, Li, Na, K, one half Ca2+, one half Mg2+ or 1/3 Fe3+;    X1, X2=one or more of three selenophen compounds e.g. formula (A);    Ra, Ra1=H, alkyl, cycloalkyl, aralkyl, aryloxy, alkoxy, alkylthio, alkyltelluro, alkyl halide, OH or halo; and    n=1-6.    An INDEPENDENT CLAIM is included for a dye-sensitized solar cell formed by a transparent base layer (1), conductive layer (2), light absorption layer (3), electrolyte layer (6) and counter electrode (7). The conductive layer, light absorption layer, electrolyte layer and counter electrode are connected sequentially between two transparent base layers. The light absorption layer is formed by a semiconductor nanoparticle layer and dye layer. The nanoparticle layer is connected with conductive layer. The dye layer is connected with electrolyte layer. The transparent base layer is formed by a glass base or plastic. The plastic is polyethylene glycol terephthalate, polyethylene naphthalene-2,6-dicarboxylate, polycarbonate, polypropylene, polyimide, triacetyl cellulose or polyether sulfone. The conductive layer is formed by indium tin oxide, fluorine tin oxide, zinc oxide (ZnO)-gallium (III) oxide, ZnO-aluminum oxide, tin-based oxide, antimony tin oxide or ZnO. The nanoparticle of semiconductor nanoparticle layer is formed by silicon, titanium dioxide, tin oxide, ZnO, tungsten trioxide, niobium pentoxide or titanium strontium oxide. An average particle diameter of semiconductor nanoparticle is 0-50 nm. The dye layer is formed by organic selenophen-containing bipyridyl ruthenium dye compound. The electrolyte layer is formed by iodine/lithium iodide electrolyte, or ionic liquid and organic hole transport material. The ionic liquid comprises two parts including anion and cation. The anion is iodide anion, bromide anion, chloride anion, dicyanamide anion, bis-(trifluoromethylsulfonyl)amine anion, hexafluorophosphate anion , tetrafluoroborate anion, nitrate anion, (C(CN)3)-, (B(CN)4)-, trifluoroacetate anion, perchlorate anion, (BF3CF3)-, (CF3SO3)-, (CF3F2SO3)-, (CH3H2SO3)-, ((CF3SO2)2N)-, ((C2H5SO2)2N)-, ((CF3SO2)3C)-, ((C2F5SO2)3C)-, ((FSO2)3C)-, ((CH3CH2OSO3))-, (CF3C(O)O)-, (CF3CF2C(O)O)-, (CH3CH2C(O)O)-, (CH3C(O)O)-, (P(C2H5)3F3)-, (P(CF3)3F3)-, (P(C2H4H)(CF3)2F3)-, (P(C2F3H2)3F3)-, (P(C2F5)(CF3)2F3)-, (P(CF3)3F3)-, (P(C6H5)3F3)-, (P(C3H7)3F3)-, (P(C4H9)3F3)-, (P(C2H5)2F4)-, ((C2H5)2P(O)O)-, ((C2H5)2P(O)O2)2-, (PC6H5)2F4)-, ((CF3)2P(O)O)-, ((CH3)2P(O)O)-, ((C4H9)2P(O)O)-, (CF3P(O)O2)2-, (CH3P(O)O2)2-, ((CH3O)2P(O)O)-, (BF2(C2F5)2)-, (BF3(C2F5))-, (BF2(CF3)2)-, (B(C2F5)4)-, (BF3(CN))-, (BF2(CN)2)-, (B(CF3)4)-, (B(OCH3)4)-, (B(OCH3)2(C2H5))-, (B(O2C2H4)2)-, (B(O2C2H2)2)-, (B(O2CH4)2)-, (N(CF3)2)-, aluminum tetrachloride anion or hexafluorosilicate anion. The cation is one or more of nine compounds e.g. formula (B). The organic hole transport material is 2,2',7,7'-tetrabis(N,N-di-P-methoxyamino)9,9'-spirobisfluorene. The counter electrode is formed by platinum, gold, nickel, copper, silver, indium, ruthenium, palladium, rhodium, iridium, osmium, carbon, and/or conductive polymers including polyaniline, polypyrrole, polythiophene or polyether.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of a dye-sensitized solar cell.    Transparent base layer (1)    Conductive layer (2)    Light absorption layer (3)    Electrolyte layer (6)    Counter electrode (7)