Molecular stacking pattern effects in heterojunction of D18:Y6 organic solar cell. Issue 5 (16th November 2022)

• Record Type: Journal Article
• Authors: Zhao, Miao; Zhang, Cai‐Rong; Zhang, Mei‐Ling; Liu, Xiao‐Meng; Gong, Ji‐Jun; Liu, Zi‐Jiang; Chen, Yu‐Hong; Chen, Hong‐Shan
• Is Part Of: International journal of quantum chemistry. Volume 123:Issue 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-16
• Subjects: electronic structure -- excitation -- molecular cluster -- molecular stacking -- organic solar cells; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.27047
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: Molecular stacking modes that determine morphology of bulk‐heterojunctions are important because of their effects on photovoltaic performance of organic solar cells (OSCs). Here, in order to investigate how molecular stacking pattern in OSCs heterojunction impact on electronic structures and properties, and then influence photovoltaic performance, this work selected D18:Y6 OSC as a representative system. On the basis of semi‐empirical quantum chemistry and density functional theory calculations, we studied the geometries, electronic structures and excitation properties, as well as electron and hole couplings of D18 and Y6 molecules, Y6 dimers, D18/Y6 and D18/Y6‐dimer complexes which are heterojunction interface models. The results indicate that the molecular stacking effects on open‐circuit voltage ( V OC ) can be attributed to the influences on charge transfer (CT) excitation energies because molecular stacking modes at donor/acceptor heterojunction interface can significantly change excitation energies. Furthermore, the molecular stacking modes can cause drastically different electron and hole couplings, and then affect charge transfer/transport rates. Hence, the molecular stacking effects on short‐circuit current density ( J SC ) can be understood from the effects on electron and hole couplings. The molecular stacking modes that are favorable to improving V OC and J SC of D18:Y6 OSC were also discussed. Abstract : This work selected D18:Y6 organic solar cells as represent system. On the basis of semi‐empirical quantum chemistry and density functional theory calculations, studied the geometries, electronic structures and excitation properties, as well as electron and hole couplings of D18 and Y6 molecules, Y6 dimers, D18/Y6 and D18/Y6 dimer complexes which are heterojunction interface models. Further, the effect of molecular stacking modes on open‐circuit voltage and short‐circuit current density were investigated.