Recently, the research group led by Professor Zhang Maojie from the National Engineering Research Center for Colloidal Materials achieved significant progress in the molecular design of donor materials for organic solar cells. The relevant research entitled “High-Efficiency Organic Solar Cells Enabled by Siloxane-Functionalized Pyrazine Terpolymers: Synergizing Performance, Morphology Control, and Non-Halogenated Solvent Processability” has been published online in the international prestigious journal Advanced Materials on May 21, 2026.

The first author of the paper is a PhD student Hou Wenwen. The corresponding authors are Prof. Zhang Maojie and Dr. Wu Jingnan. Shandong University is the primary corresponding institution for this work.

Professor Zhang’s research group has long focused on the molecular design of polymeric donors and device engineering for organic photovoltaics. Through systematic molecular engineering, the team has developed an extensive library of wide bandgap polymeric donors with fully independent intellectual property rights, driving stepwise performance improvements across the field. Most notably, the benchmark wide-bandgap polymer PM6, originally designed and synthesized by the group in 2015 (Adv. Mater., 2015, 27, 4655), is currently the most widely adopted donor material in the global organic photovoltaics community today. Building upon this foundation work, the team used an electron-deficient unit-based terpolymerization strategy to tune the aggregation behavior and optoelectronic properties of polymers, establishing a widely investigated wide-bandgap donor system with state-of-the-art comprehensive performance.

In this latest work, the research team further upgraded their previous terpolymerization design philosophy by incorporating a siloxane-functionalized, electron-deficient, and conformationally rigid DTCPz-SiO unit into the D18 polymer backbone. The resulting terpolymer DN1 exhibited improved backbone planarity, deeper HOMO energy levels, and enhanced π–π stacking with preferential face-on orientation. These molecular-level improvements translated into favorable aggregation kinetics, increased crystallinity, and optimized phase separation in the active layer. As a result, DN1:L8-BO-based devices achieved a remarkable power conversion efficiency (PCE) of 20.1% under conventional processing conditions, while maintaining high efficiencies of ∼19.5% when processed from non-halogenated solvents. The team further optimized performance using a ternary blend strategy (DN1:L8-BO:AITC), achieving record PCEs of 20.9% (halogenated solvent) and 20.0% (non-halogenated solvent), facilitating the industrial roll-to-roll manufacturing.

This work establishes siloxane-tethered rigid building blocks as an effective molecular design motif for donor polymers, enabling the simultaneous optimization of efficiency, morphological control, and non-halogenated solvent processability, and providing general design guidelines for next-generation scalable and sustainable organic photovoltaic materials.

This research was supported by the Shandong Provincial Natural Science Foundation, the Taishan Scholar Program of Shandong Province, the Distinguished Young and Middle-Aged Scholars Program and the Cheeloo Young Scholars Program of Shandong University.