Berlin 2024 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Poster III

CPP 28.28: Poster

Mittwoch, 20. März 2024, 11:30–13:30, Poster C

Illuminating the dark side of triplet states — •Mohammad Saeed Shadabroo¹, Dieter Neher², and Safa Shoaee^1,3 — ¹Optoelectronics of Disordered Semiconductors, Institute of Physics and Astronomy, University of Potsdam, Potsdam-Golm , Germany — ²Physics and Optoelectronics of Soft Matter, Institute of Physics and Astronomy, University of Potsdam, Potsdam-Golm , Germany — ³Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., 10117 Berlin, Germany

Optimization of the energy levels at the donor*acceptor interface of organic solar cells has driven their efficiencies to above 19%. However, further improvements towards efficiencies comparable with inorganic solar cells remain challenging because of high recombination losses, mediated by the lowest-energy (singlet and triplet) CT states, which empirically limit the open-circuit voltage (VOC). Using o-IDTBR blended with PM6, we achieve 1.16 V, associated with the achievement of remarkably low non-radiative recombination loss of 160 meV, despite the presence of triplets. In employing the present system as a model example, we elucidate the circumstance wherein, if the triplet lifetime surpasses that of the charge-transfer (CT) decay, the dissociation of triplet excitons to the CT state emerges as a feasible occurrence. This, in turn, serves to reduce the occurrence of an additional loss channel emanating from the T1 state. To shed light on these issues, here, an integrated approach that combines photophysics with device physics is employed in order to establish the relationships among non-radiative recombination losses mediated by the lowest states.

Keywords: Organic solar cells; Non-radiative recombination loss; Triplet exciton dissociation; Excitons; Recombination