Photophysics of Semiconductor Polymer Nanocomposite with Fullerene C.sub.60 and Endohedral Metallofullerene Ho@C.sub.82

The photoexcitation energy transfer in donor-acceptor (DA) systems formed from a mixture of semiconductor polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) with fullerene C.sub.60 and endohedral metallofullerene Ho@C.sub.82 have been investigated. It is established that the migration of excitons between polymer segments significantly affect the quenching of MEH-PPV luminescence. The Forster radii of nonradiative energy transfer are estimated for the DA systems under study. It is shown that the DA system formed using endohedral metallofullerenes is most efficient. Model photovoltaic cells with different C.sub.60 and Ho@C.sub.82 doping levels are formed based on MEH-PPV. The spectral sensitivity of photovoltage and kinetics of rise in the photovoltage signal under pulsed irradiation are measured for the formed cells. The charge carrier mobility in the polymer composites under study is estimated. It is established that a change in the endohedral metallofullerene concentration within 1-2% makes it possible to change the effective free-carrier mobility of the polymer heterojunction.