High-Performance Pseudo-Bilayer Organic Solar Cells Enabled by Sequential Deposition of D18/Y6 Chloroform Solution
Shujuan Liu, Yuchen Zhou, Zezhou Liang, Baofeng Zhao, Weiping Wang, Zeyu Xue, Kai Ding, Zhiyuan Cong, Haimei Wu, Guanghao Lu, Chao Gao
Abstract
Recently, sequential deposition (SD) fabricated pseudo-bilayer organic solar cells (OSCs) have achieved preferable performances compared to the long-term adopted bulk heterojunction (BHJ)-based devices, in which the solution-processing technique is the key to preparing the active layer of electron – donor materials and electron–acceptor materials. For devices with D18 as the electron–donor material and Y-serial small molecules as the electron–acceptor materials, however, one single solvent was seldom applied to prepare the corresponding high-performance SD OSCs. In this work, we adopted chloroform as the single solvent and successfully constructed high-performance SD OSCs based on D18 and Y6. Benefiting from the finely adjusting of the vertical phase distribution, the SD low molecular weight D18/Y6 pseudo-bilayer device realized high short-circuit current density (27.24 mA cm –2 ) and a champion efficiency of 17.94%, which surpassed the 17.36% value of the D18:Y16 device having a bulk heterojunction structure and the 7.81% result of the SD prepared Y6/D18-based device. This work demonstrates a single solvent strategy for fulfilling high-performance SD OSCs and reveals the reasons that account for the distinct performances of these OSCs fabricated by different approaches.