Improvement of the performance of inverted polymer solar cells with a fluorine-doped tin oxide electrode

Abstract

We prepared the inverted polymer solar cells (PSCs) with a fluorine-doped tin oxide (FTO) as a transparent electrode and with TiO 2, WO 3 and WO x as selective charge transport layers. An adequately thick TiO 2 nanoparticles layer was employed for covering a very rough FTO surface. Using a solution-based WO x film instead of a vacuum deposited WO 3 layer in inverted polymer solar cells showed comparable device performance. A self-assembled molecular (SAM) layer of PCBA and N719 on top of TiO 2 improves the device performance by reducing the series resistance at the interface between the active layer and the TiO 2 film. The power conversion efficiency (PCE) was improved by 16%, especially in the case of [6,6]-phenyl-C 61-butyric acid (PCBA).