Issue 32, 2019

Small energy loss in ternary organic solar cells with a blend of cascade energy levels: two fullerene-free acceptors as the electron acceptor

Abstract

Fullerene-free organic solar cells (OSCs) were fabricated using a blend of wide bandgap donor PBDB-T and ultranarrow bandgap acceptor IEICO-4F as binary photoactive layers. The ultranarrow bandgap acceptor 4TIC was selected as the third component due to the shallow lowest unoccupied molecular orbital (LUMO) energy levels, the good compatibility compared to that of IEICO-4F and the wide energy levels offset between the donor and acceptor. The power conversion efficiency (PCE) of ternary OSCs increased from 10.02% to 11.63% when 40% IEICO-4F was replaced with 4TIC, with an enhanced open-circuit voltage (VOC) of 0.82 V and without sacrificing the short-circuit current (JSC) or fill factor (FF). The main contribution of 4TIC can be summarized as the elevated LUMO level of the acceptor blended and enhanced exciton utilization of the ternary photoactive layer due to the second light absorption of 4TIC and efficient energy transfer from PBDB-T to the blended acceptor. Simultaneously, 4TIC can also act as a regulator to adjust the PBDB-T molecular arrangement for weak charge carrier recombination and optimizing charge carrier transport resulting in the lack of any decrease in the JSC and FF values of ternary OSCs even when the absorption spectrum of the ternary photoactive layer does not match the AM 1.5G solar simulator spectrum. Thus, approximately 15% PCE improvement was achieved by adopting the ternary strategy based on PBDB-T–IEICO-4F binary OSCs with a PCE of 10.02%.

Graphical abstract: Small energy loss in ternary organic solar cells with a blend of cascade energy levels: two fullerene-free acceptors as the electron acceptor

Supplementary files

Article information

Article type
Paper
Submitted
15 iyn 2019
Accepted
23 iyl 2019
First published
29 iyl 2019

J. Mater. Chem. C, 2019,7, 10039-10048

Small energy loss in ternary organic solar cells with a blend of cascade energy levels: two fullerene-free acceptors as the electron acceptor

Z. Liu and N. Wang, J. Mater. Chem. C, 2019, 7, 10039 DOI: 10.1039/C9TC03210J

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