Alkoxy replacement on asymmetric conjugated molecule enables high-efficiency ternary organic solar cells

• A study team led by Prof. Ge Ziyi at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) has actually established an alkoxy-substituted asymmetric conjugated molecule as well as doped it right into the PM6: BTP-eC9-based binary organic solar cells (OSCs) as a 3rd component, leading to high-efficiency ternary OSCs with a power conversion performance (PCE) of over 18.1%.

This work was published in ACS Energy Letters.

OSCs have drawn in a lot of interest in the clean solar energy field as a result of their remedy processability, transparency, portability, and flexibility. The ternary strategy is extensively recognized as a facile as well as efficient way to improve OSCs efficiency.

Nonetheless, to date, the "structure-performance" connection of ternary tool has actually rarely been completely and also systematically illuminated. Therefore, there is an urgent need to reveal the relationship between molecular structure, active layer morphology and photovoltaic performance to offer efficient approaches for achieving high-performance OSCs.

To address this issue, the scientists synthesized 3 asymmetric skeleton non-fullerene acceptors, i.e., TB-S, TB-S1, and TB-S1-O, as well as used them as the third component in the host binary system of PM6: BTP-eC9, respectively.

Gaining from the additional noncovalent conformation lock, the alkoxy-substituted TB-S1-O had a broad band gap, stable planar conformation, high surface area energy, exceptional compatibility with the host products, and a large ordered stacking domain, which reveals exceptional performances than TB-S, TB-S1.

Notably, the PM6: BTP-eC9: TB-S1-O ternary film has a perfect interpenetrating network, contributing to a decrease in nonradiative voltage loss as well as an improvement in charge transport. Consequently, when the scientists blended TB-S1-O into the PM6: BTP-eC9 system, a significant boost of PCE from 17.36% of binary film to 18.14% of ternary film was shown.

Due to the inferior morphology, the gadgets based on PM6: BTP-eC9: TB-S as well as PM6: BTP-eC9: TB-S1 reveal an incredibly reduced PCE (i.e., 16.16% and also 16.18%, respectively), in comparison with the PM6: BTP-eC9: TB-S1-O based ternary tool.

This work demonstrates that asymmetric skeleton with alkoxy-substitution is an efficient method to build the third component for high-performance ternary OSCs.