NOVELTY - A fullerene functionalized with at least one oxazoline or dihydro-oxazine group bound to the fullerene through a condensed ring, or through a polyvalent organic group, or directly, is new.    USE - New fullerene is used for producing linear, branched or crosslinked polymers and acceptor compound-donor compound structure, linear or crosslinked, for use in construction of photovoltaic devices e.g. photovoltaic cells, photovoltaic modules, solar cells, and solar modules (all claimed).    ADVANTAGE - The new fullerene enables construction of photovoltaic devices on both rigid and flexible supports.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) linear, branched or crosslinked polymer obtained by polymerizing and/or crosslinking the functionalized fullerene;    (2) acceptor compound-donor compound structure, linear or co-crosslinked, obtained by the reaction of functionalized fullerene(s) with photoactive organic polymer(s) functionalized with phenol, thiophenol, carboxyl and/or thiocarboxyl groups; and    (3) preparation of photovoltaic device, which involves preparing a solution including functionalized fullerene(s) of formula: Cx-(A-(-Y'-(Oxa)m)l)k, Cx(-Y'-(Oxa)m)l or Cx-(Oxa)m, photoactive organic polymer(s) (donor compound), initiator(s), and organic solvent(s), maintaining at 15-35 degrees C for 15 minutes to 48 hours, depositing the solution on an anode, after having optionally previously deposited, on the anode, layer(s) of poly(3,4-ethylene-dioxythiophene) polystyrene sulfonate, evaporating the organic solvent, forming an anode-photoactive film structure, optionally, heating the structure to 50-200 degrees C for 5 minutes to 2 hours, and depositing a cathode on the structure.    Cx=fullerene group;    x=50-250;    m=1-4;    l,k=1-3;    A=ring condensed with fullerene group chosen from 3-6C cycloalkyl or heterocyclic groups having 3-6 atoms containing 1-3 heteroatoms chosen from nitrogen, oxygen and sulfur;    Y'=polyvalent organic group having valence of m+1, chosen from linear or branched alkylene, cycloalkylene and arylene, with alkylene, cycloalkylene or arylene optionally containing in the chain heteroatom(s) chosen from oxygen, nitrogen, sulfur, silicon and phosphorus;    Oxa=oxazoline or dihydro-oxazine;    kx mx l=1;    lx m=1;and    m=1 (acceptor compound).