Enhancing the efficiency of inverted organic solar cells by employing solution processed blocking layers

Inverted organic solar cells (IOSCs) employing solution-processed blocking layers have been fabricated and characterized. A sol-gel-derived aluminum doped zinc oxide (AZO) film is used as a hole blocking layer (HBL) and a solvent-dissolved nickel oxide (NiO) is an electron blocking layer (EBL). The effects of blocking layer on the opto-electronic characteristics of IOSCs are investigated. The IOSC configuration has been optimized to be ITO/AZO/poly(3-hexylthiophene) (P3HT):phenyl C61-butyric acid methylester (PCBM)/NiO/Ag. It demonstrates a current density (J_SC) and a power conversion efficiency (PCE) of 9.25 mA/cm² and 2.04%, while an OSC without the blocking layers has PCE of 0.56%.