<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film"^^ . "Singlet fission (SF) is a process where two triplet charge-carriers are generated from one photoexcited singlet state. This opens up the possibility to increase the efficiency limit for single-junction solar cells by one third from 33% to 44%. In this work, the long-lasting question of the effect of competing pathways on the efficiency of SF is addressed by time-resolved spectroscopy and a novel global fit approach. This is demonstrated on two examples. First, SF is established in a new class of molecules, the tetraazaperopyrenes. Here, substituent-dependent factors, namely excimer formation as well as vibronic and spin-orbit coupling, are identified to be decisive for SF efficiency. Subsequently, solutions of (hetero-) acenes are investigated, in which comparisons between ambient conditions and deaerated solutions highlight the importance of molecular oxygen for SF: A new, sequential mechanism including atmospheric oxygen as a catalyst is resolved, which allows for a step-wise doubling of triplet states even at low chromophore concentrations. In concentrated solutions, diffusion-controlled SF outcompetes other reaction pathways resulting in triplet yields close to 200%. The absence of any intermediate species emphasises the efficiency of this process."^^ . "2021" . . . . . . . "Nikolaus"^^ . "Wollscheid"^^ . "Nikolaus Wollscheid"^^ . . . . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (Other)"^^ . . . . . . "medium.jpg"^^ . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (Other)"^^ . . . . . . "preview.jpg"^^ . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (PDF)"^^ . . . "Dissertation_Nikolaus_Wollscheid.pdf"^^ . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (Other)"^^ . . . . . . "small.jpg"^^ . . . "The Ultrafast Singlet Fission Dynamics in Solution and Thin Film (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #29431 \n\nThe Ultrafast Singlet Fission Dynamics in Solution and Thin Film\n\n" . "text/html" . . . "500 Naturwissenschaften und Mathematik"@de . "500 Natural sciences and mathematics"@en . .