NOVELTY - An electronic, optical or optoelectronic device comprises: first electrode, second electrode, and semiconductor component disposed between the first electrode and the second electrode.    USE - As an electronic, optical or optoelectronic device, which is used as organic photovoltaic device such as bulk heterojunction photovoltaic device, organic light emitting diode, and organic transistor such as organic thin film transistor or organic light emitting transistor (claimed).    ADVANTAGE - The device has power conversion efficiency of at least 4%; fill factor of greater than or equal to 60%, and open circuit voltage of greater than or equal to 0.7V. The copolymer exhibits properties such as excellent charge transport characteristics in ambient conditions, optimized optical absorption, chemical stability, low-temperature processability, large solubility in common solvents, and processing versatility (e.g. via various solution processes), thus incorporation of the copolymer in the device as a photoactive layer exhibits high performance in ambient conditions, e.g. demonstrating low band-gap, high fill factor, high open circuit voltage, and high power conversion efficiency. The organic semiconductor-based devices such as organic light emitting transistor fabricated efficiently using the organic semiconductor materials. The copolymers are processed into very efficient solar cells without a thermally annealing step, thus provide time- and cost-saving benefits and allow a larger variety of materials are used in various components of the solar cell.    DETAILED DESCRIPTION - An electronic, optical or optoelectronic device comprises: first electrode, second electrode, and semiconductor component disposed between the first electrode and the second electrode, where the semiconductor component comprises a copolymer of formula (I).    M'=optionally substituted benzo fused heteroaryl moiety comprising 1-6 heteroatoms and having formula (ia) or (ib);    Het=monocyclic moiety comprising at least one heteroatom in its ring;    X=N or CR3;    Y'=N or CR4;    R1-R6=H or -L'-R;    L'=O, S, or covalent bond;    R=1-40C alkyl;    R7=1-40C alkyl, 1-40C haloalkyl, 1-40C alkoxy or 1-40C alkylthio;    x and y=0.1-0.9;or    x+y=1.