Electric‐Induced Degradation of Cathode Interface Layer in PM7:IT‐4F Polymer Solar Cells

• DOI: 10.1002/solr.202100151
• Publication Date: 2021-03-05T12:49:30Z
• Authors: Tingting Dai; Xiong Li; Yingying Zhang; Xuejiao Zhou; Yaohui Zhu; Jun Zhou; Denghui Xu; Tao Lin
• Keywords: Photocurrent; Degradation; Active layer

Cathode buffer layer interface modification is a commonly used strategy to prepare high‐efficient organic solar cells (OSCs). Nonfullerene OSCs based on PM7:IT‐4F are prepared and modified with poly[(9,9‐bis(3′‐( N , ‐dimethylamino)propyl)‐2,7‐fluorene)‐alt‐2,7‐(9,9‐dioctylfluorene)] (PFN)‐Br cathode layer. The introduction of the PFN‐Br obviously boosts photovoltaic performance PM7:IT‐4F‐based OSCs, however, stability PFN‐Br‐modified device shows serious degradation. By excluding influence heat, oxygen, moisture, light illumination, degradation verified be triggered by electric effect. As soon as devices undergo electrical measurement such applying bias voltage for current density–voltage test, begins. mechanism investigated in detail intensity modulated photovoltage spectroscopy/photocurrent spectroscopy (IMPS/IMVS), photoinduced charge extraction linear increasing (Photo‐CELIV), impendence (IS) technology. results show that deteriorated increases resistance between active cathode, which hinders transport collection at electrode, thus weakening OSCs. PM7:IT‐4F/PFN‐Br induced effect proposed herein provides new inspiration study