NOVELTY - A polymer compound (I) comprises fluorene, anthracene and bithienyl thienopyrazine.    USE - Polymer compound for preparing a solar cell device, an organic electroluminescence device and a FET (all claimed).    ADVANTAGE - The polymer has low energy gap, high mobility, wide spectral absorption range and wide application range.    DETAILED DESCRIPTION - A polymer compound of formula (I) comprises fluorene, anthracene and bithienyl thienopyrazine.    n=1-100;    m=6-20;    x,y=positive real numbers;    x+y=1;    R1,R2=H, F, cyano, 1-18C alkyl, 1-18C alkoxy;and    R3=H, phenyl, 1-21C alkyl, 6-40C aralkyl or 6-40C arylalkoxy.    INDEPENDENT CLAIMS are also included for the following:    (1) a method for preparing polymer compound (I), which involves subjecting suzuki reaction compound boron substituted phenyl compound of formula (II), bromine substituted phenyl compound of formula (III) and nitrogen substituted phenyl compound of formula (IV) in an anaerobic environment in the presence of organic solvent, a catalyst and alkali solution to obtain a polymer compound of formula (I)    (2) a solar cell device comprising a conductive layer formed on a surface of a substrate as an anode, and a poly (3,4-ethylene dioxythiophene) layer formed on the conductive layer. A sodium polystyrene sulfonate layer is formed on the poly(3,4-ethylene dioxythiophene) layer. An active layer is formed on a surface of a sodium polystyrene sulfonate layer. A metal aluminum layer is formed on a surface of the active layer as a cathode. The active layer is made of electron donor material and/or an electron receptor material, where the electron receptor material is (6,6) phenyl-C61-methyl butyrate    (3) an organic electroluminescence device comprises a conductive layer formed on a surface of a substrate as an anode, and a luminescence layer formed on the conductive layer. A lithium fluoride buffer layer is formed on the luminescence layer. A metal aluminum layer is formed on the buffer layer as a cathode    (4) a field-effect transistors (FET) comprising a doped silicon wafer, a silicon dioxide insulating layer, and an octodecyl trichlorosilane layer modifying the silicon dioxide insulating layer. An organic semiconductor layer is formed on the octodecyl trichlorosilane layer. A source electrode and a drain electrode are separately arranged on the organic semiconductor layer.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a polymer compound.`(Drawing includes non-English language text)`