[{"from": "human", "value": "Given SMILES, write its solar cell poly dispersity index as a p-type polymer and PC71BM or PCBM. ->  CC1=CC(CCCCCCCCCCCC)=C(C2=CC=C(C3=CC=C(C4=C(CCCCCCCCCCCC)C=C(C5=CC=C(C6=C7C(C(N6CC(CCCC)CC)=O)=C(C8=CC=C(C)S8)N(CC(CC)CCCC)C7=O)S5)S4)S3)S2)S1\n"}, {"from": "gpt", "value": " 2.28\n"}]