Hydrothermal synthesized AZO Nanorods layer as a high potential buffer layer for inverted polymer solar cell

In this study, the performance of inverted polymer solar cell was improved using optically and electrically tuned Zn1-xAlxO (x = 0, 0.005, 0.01 and 0.015) nanorods (AZO) as a high potential electron transporting layer. AZO nanorods with different compositions were synthesized using facile, low temperature, and low cost hydrothermal method that was confirmed by energy dispersive x- ray spectroscopy (EDS) analysis. As revealed, the optical transmittance and optical band gap increased by increasing the Al concentration in AZO nanorods. The fabricated device with ITO/Zn1-xAlxO nanorods / P3HT: PCBM /WO3/Ag structure showed ascending trend for its short-circuit current density (Jsc) by increasing the amount of Al doping. The inverted polymer solar cell with 1% Al doped ZnO nanorods showed a power conversion efficiency of 3.64% that is around 40% higher than that of the device with pure ZnO nanorods (2.58%). The performance enhancement was attributed to the combined effects of the improvement in charge collection and the higher optical transmittance of AZO in the visible range.