Fabrication and characterization of MEH-PPV based bulk-heterojunction solar cell using spray deposited indium sulfide electron selective layer

ITO/In₂S₃/MEH-PPV:PCBM/Ag bulk-heterojunction device was fabricated and the effect of donor to acceptor ratio, nature of solvent and active layer thickness on the performance of the device was studied. The most favorable donor to acceptor ratio was found to be 1:4. A significant improvement in the fill factor of the device and thereby the efficiency was observed on changing the solvent from chlorobenzene to 1,2-dichlorobenzene. The fill factor improved from 28 to 37% whereas the efficiency enhanced to 0.5%. Optimum performance was found for an active layer thickness in the range 75-100nm. Stability studies revealed that the device performance degrades monotonically under continuous irradiation. A large area device was also fabricated and showed comparable performance both under indoor and outdoor conditions. The device was stored in ambient air and tested periodically. It survived for a considerable period of time without much degradation in performance indicating the interfacial stability of the device.