We present a series of organic photovoltaic (PV) cells
based on the bulk-distributed heterojunction where $\pi $-conjugated polymer
poly[1-(4-trimethylsilylphenyl)-2-phenylvinylene], PSDPhV, acts as the donor
upon photoexcitation and the substituted perylene based low-molecular-weight
compound: N,N`-di(pent-3-yl)-perylene-3,4:9,10-bis(dicarboximide),
DPe-PTCDI, as the acceptor of photogenerated electrons. According to both
absorption spectra and AFM images of the thin films spin-coated from
solution of DPe-PTCDI and PSDPhV in toluene, the DPe-PTCDI is molecularly
dissolved in conjugated polymer matrix. Upon exposition of layers to toluene
vapors, microcrystals of DPe-PTCDI are progressively formed. The influence
of the morphology of DPe-PTCDI inside the polymer matrix on PV cell
performance is investigated.