NOVELTY - A magnetic field enhanced photovoltaic device comprises a ferro/anti-ferromagnetic exchange coupling layer adjoining a photoelectric conversion layer and providing exchange coupling effects and extra magnetic bias to pin down a spin state of passing electrons generated by the photoelectric conversion layer.    USE - As e.g. P-N semiconductor solar battery, nano-rod solar battery or dye-photoactivated solar battery.    ADVANTAGE - The invention enhances the efficiency of the photovoltaic device. The additional magnetic field in the photovoltaic device will polarize the spin state of electrons that migrate inside the photovoltaic device. A ferro/anti-ferromagnetic layer interfacing with a coupling layer produces an exchange coupling effect and pins the spin state of electrons, which reduces scattering probability during electron transmission, reduces internal resistance and increases conversion efficiency.    DETAILED DESCRIPTION - A magnetic field enhanced photovoltaic device comprises a photoelectric conversion layer to receive incident light and produce electrons and holes; a first electrode and a second electrode located on two sides of the photoelectric conversion layer to collect passing electrons and holes in order to produce electrical energy, wherein the first electrode is pervious to light and allows light to reach the photoelectric conversion layer; an applied magnetic field exerted on the photoelectric conversion layer to force passing electrons' spin state consistent with the applied magnetic field; a ferro/anti-ferromagnetic exchange coupling layer (140) adjoining the photoelectric conversion layer and providing exchange coupling effects and extra magnetic bias to pin down a spin state of passing electrons generated by the photoelectric conversion layer.    DESCRIPTION OF DRAWING(S) - The figure shows a cut-cross display of a photovoltaic device.    Substrate (100)    First transparent layer (110)    Nickel electrode (120)    P-N junction semiconductor layer (130)    Ferro/anti-ferromagnetic exchange coupling layer (140)    Nickel layer (141)    Nickel oxide layer (142)    FTO electrode (150)