Regensburg 2019 – wissenschaftliches Programm

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

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 50: Organic Electronics and Photovoltaics III - Organic Photovoltaics

CPP 50.1: Vortrag

Donnerstag, 4. April 2019, 09:30–09:45, H18

Achieving supressed recombination; kinetics of singlet and triplet charge transfer states defining charge generation and recombination in organic solar cells — •Safa Shoai — University of Potsdam

In-depth understanding of charge carrier photogeneration and recombination mechanism in organic solar cells is still an ongoing effort in the community. In donor:acceptor (bulk) heterojunction organic solar cells charge photogeneration and recombination are inter-related via the kinetics of charge transfer states. While efficient charge photogeneration quantum yield can be achieved in many donor:acceptor systems, only very few systems have so far shown significantly reduced bimolecular recombination coefficient. Herein, we present a meta-analysis of the device performance for numerous BHJ OSC for which field dependent photogeneration, charge carrier mobility and fill factor are determined. From this analysis we find a spin-related factor which is dependent on the ratio of back electron transfer of the triplet CT states to the decay rate of the singlet CT states. This factor along with the dissociation efficiency of the CT states primarily define the charge generation efficiency and bimolecular recombination reduction factor. In systems with extremely efficient charge generation due to the very fast dissociation rate of the CT states, the recombination can be strongly suppressed regardless of the spin-related factor.