Light manipulating electrode based on high optical haze aluminum-doped zinc oxide for highly efficient indium-tin-oxide free organic solar cells with over 13% efficiency

Abstract

In this paper, highly efficient Indium-Tin-Oxide (ITO) free organic solar cells (OSCs) are fabricated by employing a light manipulating electrode based on high optical haze textured Al-doped zinc oxide (Textured-AZO) film. The Textured-AZO film is fabricated by a tunable acidic gas etching method with high haze value up to 85% and high total transmittance about 87%, which elongates the optical path length and enhances the light absorption of OSCs. As a result, by employing PBDB-T-2F:IT-4F as the photoactive layer, the device based on the Textured-AZO electrode shows much improved J_sc compared to the device based on the Flat-AZO electrode (22.11 mA cm⁻²vs. 19.86 mA cm⁻²), resulting in a promising power conversion efficiency (PCE) of 13.11%. The high PCE is among the best results for ITO-free OSCs reported so far. More significantly, the Textured-AZO based device even shows higher J_sc and PCE than the ITO-based device (PCE = 12.86%, J_sc = 20.93 mA cm⁻²), indicating a great potential of using Textured-AZO as a transparent conducting electrode in future commercialization of OSCs.