Influence of up-side-down drying and thermal annealing treatment on performance of P3HT: PCBM-based solar cells

The effect of up-side-down drying treatment to the organic solar cells based on poly(3-hexylthiophene)(P3HT):[6, 6]-phenyl-C61-butyricacid methylester (PCBM) blend was investigated, and the affects of different treatments on the devices were discussed. Multiple devices with the structure ITO/PEDOT: PSS/P3HT: PCBM/Ca/Al have been fabricated. Effects of different drying treatments on the devices performance were systematically investigated. With an up-side-down treatment of the wet layer in the drying process, the PCE of the device was apparently improved compared to a reference device. Compared to the normal drying the up-side-down drying have a greater impact on the active layer microstructure by SEM and AFM characterization. The polymerization and orientation of the material became better. Our results also show that up-side-down treatment can enhance the PCE and FF for various thickness blend devices.