A chlorinated low-bandgap small-molecule acceptor for organic solar cells with 14.1％ efficiency and low energy loss

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2018,（10）
• 页码范围: 1307-1313
• 页数: 7页
• 语种: 英文

摘要

A new acceptor-donor-acceptor (A-D-A) type small-molecule acceptor NCBDT-4Cl using chlorinated end groups is reported.This new-designed molecule demonstrates wide and efficient absorption ability in the range of 600-900 nm with a narrow optical bandgap of 1.40 eV.The device based on PBDB-T-SF:NCBDT-4Cl shows a power conversion efficiency (PCE) of 13.1％ without any post-treatment,which represents the best result for all as-cast organic solar cells (OSCs) to date.After device optimizations,the PCE was further enhanced to over 14％ with a high short-circuit current density (Jsc) of 22.35 mA cm-2 and a fill-factor (FF) of 74.3％.The improved performance was attributed to the more efficient photo-electron conversion process in the optimal device.To our knowledge,this outstanding efficiency of 14.1％ with an energy loss as low as 0.55 eV is among the best results for all single-junction OSCs.