IDT-2Br

General description

Non-fullerene acceptors (NFAs) are currently a major focus of research in the development of bulk-heterojunction organic solar cells (OSCs). In contrast to the widely used fullerene acceptors (FAs), the optical properties and electronic energy levels of NFAs can be designed and readily tuned. NFA-based OSCs can also achieve greater thermal stability and photochemical stability, as well as longer device lifetimes, than their FA-based counterparts.Recent developments have led to a rapid increase in power conversion efficiencies for NFA OSCs, with values now exceeding 15% in a single junction cell, and >17% for a tandem cell, demonstrating the viability of using NFAs to replace FAs in next-generation high-performance OSCs.

Application

IDT-2BR is amedium-high bandgap nonfullerene acceptors (NFAs) which can be utilized as ap-dopant in the fabrication of p-type organic semiconductors for OFETs (OrganicField-Effect Transistors). IDT-2Br is used as a halogen-based flame retardantadditive in the production of printed circuit boards (PCBs). It helps improvethe fire resistance of PCB materials, ensuring their safety during use. It canbe incorporated into the polymer or small molecule-based photoactive materials,contributing to the absorption of light and facilitating charge generation inthe OPV device. Its presence in the active layer can help enhance the lightabsorption and power conversion efficiency of the solar cell.

IDT-2BR is a medium-high bandgap nonfullerene acceptors (NFAs). It was reported that IDT-2BR could produce a high power conversion efficiency (PCE) of over 10% when used with low-bandgap p-type polymer PTB7-Th (Product No. 794333). A prominent feature of this blend is the very small energy loss (< 0.6 eV) in the cell, which allows for a very high open circuit voltages in the device (> 1 V).
Ternary blend organic solar cells (OSCs) with photoresponses beyond 1000 nm can be fabricated using PTB7-Th as donor and ultralow-bandgap F8IC and medium-high bandgap IDT-2BR as NFAs. A PCE of 12.1% has been achieved by such a ternary device with 20% IDT-2BR content in acceptors. In this work, IDT-2BR was found to contribute simultanously to the improvement of the open-circuit voltage (VOC), short-circuit (JSC) and fill factor (FF) of the PTB7-Th/F8IC blend, due to smaller energy offset for charge separation, suppressed charge recombination, and imporved light absorption. Improved packing due to the coexsitence of F8IC and IDT-2BR leads to higher mobilities and more balanced charge transport, which contribute to the improved FF as well.
Additionaly, blends with IDT-2BR have been found to be thermally stable at 150 Celsius.
A ternary blend using both IDT-2BR and fullerene based acceptor: PC71BM (Product No. 684465) has also reached a PCE over 12%.