Abstract: Large-area inverted polymer solar cells with a device structure of ITO/ZnO/P3HT∶PCBM/V2O5/Ag(P3HT:poly(3-hexylthiophene); PCBM:[6,6]-phenyl C61-butyric acid methyl ester) were prepared with an active area of 1.0×1.1 cm2 by spray coating technique. UV-Vis absorption spectrum of the P3HT∶PCBM film indicated that the absorbance was dramatically strengthened, and the absorption peaks were red-shifted to some extent. ZnO and V2O5 were used to replace LiF and PEDOT∶]PSS(4-ethylenedioxythiophene∶polystyrene sulfonate) as the interfacial modified layers, in order to avoid corrosion of PEDOT∶PSS to ITO layer and deliquescence of LiF. In addition, Ag instead of Al was evaporated as the back electrode to avoid the oxidization of Al electrode. The efficiency of the device increased from 1.1% to 1.65% after thermal annealing. The stability of the inverted devices was markedly improved compared with traditional devices, with the efficiencies decreased by only 10% after storage for 8 weeks.

Key words: spray coating, polymer solar cells, P3HT:PCBM, ZnO nanoparticles