Photophysics of semiconductor polymer nanocomposite with fullerene С$_{60}$ and endohedral metallofullerene Ho@C$_{82}$

The photoexcitation energy transfer was studied in donor-acceptor systems (DA) formed from a mixture of the semiconductor polymer poly [2-methoxy-5-(2'-ethylhexyloxy) -1,4-phenylenevinylene] (MEH-PPV) with C60 fullerene and endohedral metallofullerene Ho@C$_{82}$. A significant effect of the exciton migration between the polymer units on the quenching of MEH-PPV luminescence has been established. The Foerster radii of nonradiative energy transfer for the investigated DA systems are estimated. It is shown that the DA system formed using endohedral metallofullerenes is the most effective. Based on MEH-PPV, model photovoltaic cells with different doping levels С$_{60}$ and Ho@C$_{82}$ were formed. For the formed cells, the spectral sensitivity of the Photo-EMF and the kinetics of the increase in the Photo-EMF signal under pulsed irradiation were measured. The mobility of charge carriers in the studied polymer composites was estimated. It was found that a change in the concentration of endohedral metallofullerene within 1–2% allows you to change the effective mobility of free carriers of the polymer heterojunction.