A universal three-dimensional metal-organic frameworks assisted strategy facilitates non-covalent interaction of active/interfacial layers for over 19 % efficiency organic photovoltaics

Abstract

The cathode interfacial layer (CIL) plays a crucial role in facilitating the efficient flow of electrons from the active layer to the metal electrode in organic photovoltaics (OPVs). In this work, we intelligently designed and synthesized a three-dimensional metal-organic frameworks (MOFs) material namely Ag-Zn-N/C, and firstly employ it as inorganic nanoparticle dopants for PFN-Br interlayer. The three-dimensional Ag-Zn-N/C possess tremendous surface area that can serve as the nucleation center, regulating the PFN-Br crystal, restraining Br ions induced dipole adsorption that facilitates electron transport, mitigating the excessive charge accumulation caused by the -CN functional group, and thus enhancing the electron extraction of PFN-Br interlayer and contributing to the formation of fast electron transfer network from ITIC to PFN-Br. As a consequence, the power conversion efficiency (PCE) of PBDB-T:ITIC-based OPVs boosted from 10.92 % to 12.63 %, delegating one of the supreme PCE values of this system. In addition, the Ag-Zn-N/C doping PFN-Br strategy was demonstrated to be general for different OPV systems. For example, upon the introduction of Ag-Zn-N/C, the PCE of the current mainstream systems PM6:L8-BO and D18:L8-BO has also been effectively enhanced from 16.21 % and 17.86 % to 17.55 % and 19.16 %, respectively. Our work can provide a simple and efficient approach for designing efficient CIL to boost the PCE of OPVs, which may further advance the commercialization of OPVs.