Pivotal factors in solution-processed, non-fullerene, all small-molecule organic solar cell device optimization

The importance of device structure and active-layer processing when screening non-fullerene acceptors was demonstrated through the organic solar cell device performance optimization of a solution processable non-fullerene, all small-molecule bulk heterojunction (BHJ) blend. Key tuning parameters were identified; notably, the largest improvement in performance was achieved by switching from the conventional device architecture (ITO/PEDOT:PSS/D-A BHJ/Ca/Al) to an inverted structure (ITO/ZnO/D-A BHJ/MoOx/Ag), approximately doubling the power conversion efficiency from best cells of 0.5%-1.0%, demonstrating the importance of investigating more than a single architecture when screening novel non-fullerene acceptors. (C) 2015 Elsevier B.V. All rights reserved.