On the impact of the energy level offset on carrier recombination in organic non-fullerene acceptor-based solar cells
Safa Shoaee a
a Disordered Semiconductor Optoelectronics, Institute of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
Materials for Sustainable Development Conference (MATSUS)
Proceedings of MATSUS23 & Sustainable Technology Forum València (STECH23) (MATSUS23)
#NewOPV - New concepts for stable non-fullerene based organic solar cells and their applications
VALÈNCIA, Spain, 2023 March 6th - 10th
Organizers: Vida Engmann, Morten Madsen and Pavel Troshin
Invited Speaker, Safa Shoaee, presentation 226
DOI: https://doi.org/10.29363/nanoge.matsus.2023.226
Publication date: 22nd December 2022

The energetic offset between the highest occupied molecular orbital (HOMO) levels of the donor and acceptor components of the organic photovoltaic (OPV) blends is well-known to affect the efficiency of the singlet exciton (S1) dissociation into separated charges (CS) via the chargetransfer (CT) state, however the impact of this offset on bimolecular recombination of free charge carriers has not been explored. In this study, using different non-fullerene acceptors blended with the same donor polymer PM6, we demonstrate that, apart from reducing the driving force for charge generation, diminishing HOMO-HOMO energy offset also activates faster bimolecular recombination of free charges either through the CT state or through exciton reformation as a new channel. Using the comparison between PM6:ITIC and PM6:o-IDBTR, we show that neither morphology, nor carrier mobilities can on their own explain the observed difference in performance, signaling the importance of the energy landscape in controlling the OPV device efficiency, both through generation and recombination of charge carriers.

© FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info