Effective light trapping enhanced near-UV/blue light absorption in inverted polymer solar cells via sol-gel textured Al-doped ZnO buffer layer

The effects of sol-gel textured Al-doped ZnO (AZO) cathode buffer layer on the performance of the inverted polymer solar cells have been investigated in this work. Textured AZO, together with a reflective back electrode provides efficient light-trapping, inducing further light absorption in the active layer. The AZO films were characterized with respect to their morphology, optical and electrical properties. Due to the enhanced absorption at near-UV/blue light region (300-500 nm), the short current density of the textured-AZO device is increased from 9.52 to 11.30 mA/cm(2) compared with the reference cell based on the flat-AZO. Power conversion efficiency is increased substantially from 2.44% to 2.87% since without loss in the fill factor and open circuit voltage. (C) 2013 Elsevier B.V. All rights reserved.