Charge-Transfer State Dynamics Following Hole and Electron Transfer in Organic Photovoltaic Devices - Bakulin,AA; Dimitrov,SD; Rao,A; Chow,PCY; Nielsen,CB; Schroeder,BC; McCulloch,I; Bakker,HJ; Durrant,JR; Friend,RH (JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 2013)