NOVELTY - A polymerizable fullerene derivative (I) comprising a fullerene core containing 60C or 70C fullerene, a bridging functional group connected to a surface of the fullerene core and comprising cyclic hydrocarbon or a heterocyclic ring, and a polymerizable functional group connected to the bridging functional group and comprising a thermally polymerizable functional group or a photochemically polymerizable functional group, is new.    USE - In an inverted organic photovoltaic cell (claimed).    ADVANTAGE - The inverted organic photovoltaic cell comprising the interlayer made of polymerizable fullerene derivative has enhanced device performance and lifetime. Because the polymerizable fullerene derivatives are highly amorphous after the polymerization process and has high glass transition temperature (near 150 degrees C), the morphology of the polymerizable fullerene derivative interlayer possesses high thermal stability and not easily becomes cluster or crystallite during or following thermal treatment. The inverted organic photovoltaic cell comprising the interlayer made of the polymerizable fullerene derivatives can be used as an electron-selective layer. Thus, the interlayer made of the polymerizable fullerene derivatives not only increases the electron capture efficiency but also be a hole blocking layer so as to decrease the loss of electron/hole pairs in the vicinity of the interface of the active layer and the metal oxide layer and increases the photoelectric conversion efficiency. Since the interlayer made of the polymerizable fullerene derivatives has hotspot passivation, the leakage current can be prevented. The interlayer can form an additional p-n local hetero-junction with electron donors in the active layer and practice ultra fast electron transfer more efficiently than the hetero-junction formed in between the metal oxide and electron donors so as to increase the exciton dissociation efficiency. The interlayer provides the nucleation site of the electron acceptor, which is (6,6)-phenyl-61C-butyric acid methyl ester and indene-60C-bisadduct, in the bulk hetero-junction active layer to induce that the active layer generates the effective lateral micro-phase separation and simultaneously increase the crystallinity of electron donors. The interlayer is an anti-etching and stable thin film, such that the interlayer has solvent resistance property to resist the wet etching from the coating solvent during the subsequent procedure. Thus, manufacturing of organic photovoltaic cells via the wet process is achieved, and the manufacturing cost is effectively reduced.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an inverted organic photovoltaic cell, comprising: an interlayer (30) made of the polymerizable fullerene derivative, and disposed between a metal oxide layer (20) and an active layer (40).    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of the structure of an inverted organic photovoltaic cell.    Transparent conducting layer (10)    Metal oxide layer (20)    Interlayer made of the polymerizable fullerene derivative (30)    Active layer (40)    Hole-selective layer (50)    Metal electrode layer (60)