Probing the pathways of free charge generation in organic bulk heterojunction solar cells

• DOI: 10.1038/s41467-018-04386-3
• Publication Date: 2018-05-17T13:43:32Z
• Authors: Jona Kurpiers; Thomas Ferron; Steffen Roland; Marius Jakoby; Tobias Thiede; Frank Jaiser; Steve Albrecht; Silvia Janietz; Brian A. Collins; Ian A. Howard; Dieter Neher
• Keywords: Charge carrier; Photon energy

The fact that organic solar cells perform efficiently despite the low dielectric constant of most photoactive blends initiated a long-standing debate regarding dominant pathways free charge formation. Here, we address this issue through accurate measurement activation energy for photogeneration over wide range photon energy, using method time-delayed collection field. For our prototypical bandgap polymer:fullerene blends, find neither temperature nor field dependence generation depend on excitation ruling out an appreciable contribution to though hot carrier pathways. On other hand, energies are order room thermal all studied blends. We conclude in such devices proceeds thermalized transfer states, and is sufficient separate these states into charges.