Charge-transfer character of excitons in poly[2,7-(9,9-di-n-octylfluorene)(1-x)-co-4,7-(2,1,3-benzothiadiazole)(x)] - Winfield,JM; Van,Vooren A; Park,M-J; Hwang,D-H; Cornil,J; Kim,J-S; Friend,RH (JOURNAL OF CHEMICAL PHYSICS, 2009)