Issue 39, 2020

Multi-channel exciton dissociation in D18/Y6 complexes for high-efficiency organic photovoltaics

Abstract

Interfacial charge transfer between the donor and acceptor plays a crucial role in determining the photo-induced charge generation mechanisms and efficiencies for organic solar cells. Here, we have theoretically investigated the exciton-dissociation and charge-recombination processes in complexes consisting of a wide-bandgap polymer donor D18 and a narrow-bandgap small-molecule acceptor Y6, which exhibit the best organic photovoltaic performance to date. The results show that besides the lowest charge-transfer (CT0) state, there are also four higher-lying CT states below the lowest singlet excited state (S1) of D18, and the excitons on D18 will dissociate into the higher-lying CT states much faster (1010–1012 s−1) than into the CT0 state (107–108 s−1). In contrast, only the CT0 state is below the S1 state of Y6 due to the small driving force for hole transfer from Y6 to D18, while the dissociation rates of Y6 excitons into the CT0 state can be very high (1013 s−1). Importantly, the rates of charge recombination are mostly lower than 106 s−1. These results are fully consistent with the highly efficient exciton dissociation and low charge recombination observed by experiments. Our work underlines the importance of multi-channel exciton dissociation for high-efficiency organic photovoltaics.

Graphical abstract: Multi-channel exciton dissociation in D18/Y6 complexes for high-efficiency organic photovoltaics

Supplementary files

Article information

Article type
Paper
Submitted
14 Aug 2020
Accepted
11 Sep 2020
First published
11 Sep 2020

J. Mater. Chem. A, 2020,8, 20408-20413

Multi-channel exciton dissociation in D18/Y6 complexes for high-efficiency organic photovoltaics

Z. Cao, S. Yang, B. Wang, X. Shen, G. Han and Y. Yi, J. Mater. Chem. A, 2020, 8, 20408 DOI: 10.1039/D0TA07996K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements