Numerical investigation of PBDB-T:INTIC based bulk heterojunction organic solar cell with graphene derivatives as HTL

Graphene derivatives, with their exceptional mobility and tunable optical bandgap, have emerged as promising candidates as interfacial layers, particularly as hole transport layers (HTLs) in bulk heterojunction organic solar cells (BHJOSCs). Their two-dimensional structure, coupled with outstanding chemical, mechanical, and optoelectronic properties makes them suitable for charge transport in small molecule non-fullerene acceptor (SM-NFA)-based BHJOSCs. INTIC a rarely studied SM-NFA is used for this study due to its superior near-infrared absorption and smaller bandgap compared to other NFAs. In this study, we perform a numerical investigation of BHJOSCs with PBDB-T:INTIC as the active layer with graphene derivatives as transport layers, mainly as hole transport layer utilizing SCAPS-1D software. We first validate the software using a reference device structure of ITO/PEDOT:PSS/PBDB-T:NCBDT/PDINO/Al, as reported experimentally. Next, we replace the non-fullerene acceptor NCBDT with INTIC. Additionally, graphene derivatives are explored as replacements for the conventional PEDOT:PSS HTL, owing to their enhanced role in charge extraction, transport, and their ability to provide protection against environmental degradation and improved durability. Specifically, graphene, p-graphene, graphene oxide (GO), and reduced graphene oxide (rGO) are employed as HTLs. Various electron transport layer (ETL) materials, including TiO 2 :gr(20%), TiO 2 :gr(10%), PDINO, PFN-Br and IGZO, are also used for the simulation study. The results indicate that the most effective device configuration is ITO/rGO/PBDB-T:INTIC/PDINO/Al, which achieves a Voc of 0.73 V, Jsc of 19.97 mA/cm 2 , FF of 76.95%, and an efficiency of 11.22%. • A novel PBDB-T:INTIC based BHJOSC with graphene derivatives as transport layers is numerically simulated and investigated • INTIC, a low bandgap small molecule non-fullerene acceptor, with good near infrared absorption is used • Graphene derivatives namely graphene, p-graphene, graphene oxide and reduced graphene oxide is used as hole transport layers • Highest efficiency is obtained for device configuration with reduced graphene oxide as hole transport layer.