The Polymer Society of Korea

Abstract

Organic solar cells (OSCs) have achieved remarkable power conversion efficiencies, yet their long-term thermal stability remains a critical challenge for practical deployment. Here, we report a strategy to enhance high-temperature stability by incorporating an ionic dopant, DBBB-SO₃Cu, into the active layer. The introduction of this dopant improves morphological robustness and suppresses thermally induced phase separation, leading to sustained device performance under elevated operating conditions. OSCs with DBBB-SO₃Cu exhibit not only improved thermal endurance but also enhanced charge transport and reduced trap-assisted recombination, thereby maintaining high efficiency after prolonged thermal stress. These results highlight the potential of ionic dopants as an effective design principle for stabilizing organic photovoltaic devices and advancing their applicability in real-world environments.