This manuscript presents a systematic and well-rounded study on the role of fullerene derivatives (PC₆₁BM and PCBC6) as third components in PM6:L8-BO-based ternary OPVs. The work effectively addresses trap-assisted recombination and morphological instability through controlled morphology modulation. The study is scientifically sound, methodologically rigorous, and clearly written. However, several aspects require clarification and refinement before publication.
Major Comments
The reported PCE improvement (17.28% → 18.38%) is modest. The authors should better emphasize the novel aspects, particularly the use of PCBC6, AFM–IR mapping, and integration with in-situ spectroscopies and MD simulations.
Include a comparative summary table of recent ternary OSCs (composition, PCE, Voc, FF, stability) to highlight how this work advances mechanistic understanding and stability optimization beyond prior studies.
Incorporate AFM–IR mapping to visualize blend morphology evolution. Explicitly link morphological uniformity (e.g., reduced phase contrast, continuous donor/acceptor domains) with enhanced thermal and photostability under ISOS-L1-I and ISOS-D2-I protocols.
If possible, add quantitative AFM–IR metrics such as domain size distribution or correlation length to support the morphology–stability relationship.
Strengthen the link between TPV/TPC/SCLC data and the observed Voc and FF improvements.
Clarify whether the Voc enhancement arises from reduced non-radiative recombination or favorable energetic alignment due to the fullerene LUMO levels.
For stability, include quantitative stability metrics such as T₈₀, activation energies (if extractable), and normalized PCE decay plots.
Correlate the claim that “fullerenes alter degradation pathways” with specific spectroscopic features (e.g., Raman peak shifts, absorption edge variations).
Minor Comments
Correct minor grammatical issues (e.g., “regulating the morphological of the photo-active layer” → “regulating the morphology of the photo-active layer”).

The authors has addressed the reviewers comments