Organic photovoltaics (OPVs ) with bulk heterojunction (BHJ) structure have attracted widespread attention in the field of clean solar energy due to their advantages such as solution processability, transparency, portability, and flexibility. The ternary strategy, as an effective and simple approach, can significantly enhance the power conversion efficiency (PCE) of OPVs.
1. Introduction and Review
Organic photovoltaics (OPVs) with a bulk heterojunction (BHJ) structure have gained significant attention in the field of clean solar energy due to their advantages such as solution processability, transparency, portability, and flexibility. The ternary strategy, as an effective and simple method, has the potential to significantly improve the power conversion efficiency (PCE) of OPVs. However, most of the research in this area has focused on individual guest components without systematic studies on analogs. Therefore, further understanding is needed regarding the correlation between the molecular structure of the third component, the morphology of the active layer, and the photovoltaic performance of ternary devices.
Since 2019, Y6 derivatives, especially symmetrical molecules, have become a research hotspot in OPVs due to their excellent performance characteristics such as narrow bandgap and high electron mobility. In addition to symmetrical non-fullerene acceptors, asymmetric non-fullerene (ANF) acceptors have also been successfully applied in OPVs. Typically, ANF acceptors can be categorized as asymmetric skeleton-type (ASNF, A-D1A′D2-A) and asymmetric end-group-type (ATNF, A1-DA′D-A2). Recently, ternary OPV devices using ATNF acceptors as the third component have achieved outstanding PCE exceeding 19%. However, there has been no research or report on the use of ASNF acceptors as the third component so far.
Molecular Structure Properties and Contact Angle Testing
2. Literature Introduction
In order to reveal the intrinsic properties of ASNF molecules, the morphology of the active layer, and the photovoltaic performance of ternary OPV devices, recently, researchers from the Chinese Academy of Sciences (CAS) have designed and synthesized two novel ASNF acceptors with wider bandgaps, namely TB-S1 and TB-S1-O. In previous work, it was reported that the TB-S series of ANF molecules have similar backbones but different end groups or alkyl/alkoxy side chains. The researchers incorporated these three molecules as the third component into the main system of PM6:BTP-eC9 for investigation.
Comparison of Photovoltaic Performance among Different Devices
Characterization of Morphology in Different Devices
3. Literature Summary
In summary, this study demonstrates that alkoxyl substitution on asymmetric main chains is an effective method for constructing high-performance third components in ternary OPVs. The research findings were recently published in the prestigious journal "ACS Energy Letters" under the title "Alkoxy Substitution on Asymmetric Conjugated Molecule Enabling over 18% Efficiency in Ternary Organic Solar Cells by Reducing Nonradiative Voltage Loss".
Keywords: Organic solar cells, asymmetric fullerene acceptors, ternary devices, asymmetric substitution.