Morphological Stabilityof a Quinoxaline-Based Double-CableConjugated Polymer under Thermal Stress

We present a quinoxaline-based double-cable polymer (QDCP) with a naphthalenediimide (NDI) acceptor pendant designed for enhanced morphological stability in organic solar cells (OSCs). QDCP exhibited superior thermal stability compared to PTQ11, a quinoxaline-based conjugated polymer, and an NDI blend. While the PTQ11:NDI blend showed severe aggregation and reduced charge mobility after thermal treatment (150 °C, 10 min), QDCP maintained its morphology and enhanced mobility. Moreover, QDCP-based OSCs retained 90% of their initial power conversion efficiency (PCE) after 120 h of thermal stress at 80 °C, whereas the PTQ11:NDI blend suffered significant performance loss.