title: 1,8-Naphthalimide-Based Planar Small Molecular Acceptor for Organic Solar Cells.
abstract: Four small molecular acceptors (SM1-4) comprising a central benzene core, two thiophene bridges and two 1,8-naphthalimide (NI) terminal groups were designed and synthesized by direct C-H activation. SM1 has a planar chemical structure and forms H-aggregation as films. By attachment of different substituents on the central benzene ring, the dihedral angles between the two NI end groups of SM1-4 gradually increased, leading to a gradual decrease of planarity. SM1-4 all possess a high-lying LUMO level, matching with wide band gap (WBG) polymer donors which usually have a high-lying LUMO level. When used in OSCs, devices based on SM1 and WBG donor PCDTBT-C12 gave higher electron mobility, superior film morphology and better photovoltaic performance. After optimization, a PCE of 2.78% with a V(oc) of 1.04 V was achieved for SM1 based devices, which is among the highest PCEs with a V(oc) higher than 1 V. Our results have demonstrated that NI based planar small molecules are potential acceptors for WBG polymer based OSCs.
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Jicheng
authors: J
authors: Zhang
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Xuejuan
authors: X
authors: Zhang
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Hongmei
authors: H
authors: Xiao
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Guangwu
authors: G
authors: Li
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Yahui
authors: Y
authors: Liu
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Cuihong
authors: C
authors: Li
authors: College of Materials Science and Optoelectronic Technology University of Chinese Academy of Sciences , No.19A Yuquan Road, Beijing, 100049, China.
authors: Hui
authors: H
authors: Huang
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Xuebo
authors: X
authors: Chen
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Zhishan
authors: Z
authors: Bo
keywords: C−H activation; H-aggregation; high open circuit voltage; nonfullerene acceptor; organic solar cells; planar small molecules; wide band gap polymer