Issue 13, 2023

Aggregation state tuning via controlling molecular weights of D–A1–A2 type polymer donors for efficient organic photovoltaics

Abstract

Thiophene ring-based polymer donors generally face the challenges of high-lying energy levels and unfavorable aggregation states, thus limiting the performances of thiophene-based organic photovoltaics (OPVs). Herein, different from the traditional donor–acceptor (D–A) structure, we proposed a novel molecular design strategy of polymer donors by constructing a D–A1–A2 structure to achieve deep-lying energy levels, yielding PQC-TL, PQC-TM and PQC-TH, whose aggregation states in films could be controlled via molecular weights. A comparable study was performed by pairing these polymer donors with a newly synthesized monochlorinated non-fullerene acceptor L8-Cl. It's found that increasing the molecular weights of polymer donors leads to strengthened aggregation and reduced miscibility between the donor and acceptor, thus manipulating the domain sizes and crystallinity in polymer donor:L8-Cl blend films. An OPV device based on a PQC-TM donor with a medium molecular weight achieves a good balance between high crystallinity for efficient charge transport and suitable domain sizes for least charge recombination, thus enabling the highest efficiency of 15.0%, much higher than those (12.7% and 11.3%) of PQC-TL and PQC-TH-based devices. Anyway, this work demonstrates D–A1–A2 as a feasible molecular structure for designing efficient thiophene ring-based polymer donors and shows the critical role of molecular weight in controlling the aggregation state and device performance.

Graphical abstract: Aggregation state tuning via controlling molecular weights of D–A1–A2 type polymer donors for efficient organic photovoltaics

Supplementary files

Article information

Article type
Paper
Submitted
22 12 2022
Accepted
28 2 2023
First published
28 2 2023

J. Mater. Chem. A, 2023,11, 6997-7005

Aggregation state tuning via controlling molecular weights of D–A1–A2 type polymer donors for efficient organic photovoltaics

S. Wang, T. Chen, S. Li, L. Ye, Y. Fu, X. Lu, H. Zhu, L. Zuo, M. Shi and H. Chen, J. Mater. Chem. A, 2023, 11, 6997 DOI: 10.1039/D2TA09936E

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