The current–voltage characteristics and photovoltaic parameters of polymer solar cells with Al cathode separately deposited by thermal and electron beam methods were compared. The power conversion efficiency of as prepared electron beam deposited device is ten times lower than that of thermal evaporated one. However, after post-annealing, device performance parameters of electron beam deposited device sharply increased and reached almost the same values as thermal evaporated device. Through the analysis of J-V characteristics in the dark, the formation of deep traps at the interface induced by electron beam, as reported in earlier studies, was excluded.