Issue 11, 2017

An extended π-conjugated area of electron-donating units in D–A structured polymers towards high-mobility field-effect transistors and highly efficient polymer solar cells

Abstract

Two D–A conjugated polymers, FBT-DThDT-1T and FBT-DThDT-TT, using 5,6-difluoro-2,1,3-thiadiazole (FBT) as the electron-accepting unit, and terthiophene or 2,5-di(thiophen-2-yl)thieno[3,2-b]thiophene as the electron-donating unit, respectively, were synthesized. Among them, the first batch of FBT-DThDT-TT with relatively low molecular weight (MW) can be denoted as FBT-DThDT-TT-L and the second batch of FBT-DThDT-TT with much higher MW can be denoted as FBT-DThDT-TT-H. FBT-DThDT-1T possesses a low FET hole mobility of 2.6 × 10−3 cm2 (V s)−1 and a poor power conversion efficiency (PCE) of 0.91% in inverted polymer solar cells (i-PSCs) under the illumination of AM1.5G, 100 mW cm−2 light. Compared with FBT-DThDT-1T, FBT-DThDT-TT with extended π-conjugation bears a TT replacing the middle thiophene of terthiophene on the backbone, which would increase the coplanarity of the polymer and thus facilitate both intermolecular packing and charge transport. FBT-DThDT-TT shows strong interchain aggregation in a room temperature solution, its absorption spectra in a room temperature solution and in a thin film were almost identical. The field-effect transistors based on FBT-DThDT-TT-L and FBT-DThDT-TT-H show improved hole mobilities of 0.38 and 0.20 cm2 (V s)−1, respectively. The i-PSCs based on FBT-DThDT-TT-L show a better PCE of 3.47%, and the i-PSCs based on FBT-DThDT-TT-H with a higher MW exhibit the best PCE up to 7.78%, with highly improved absorption capacity and miscibility with PC71BM. Moreover, with a 355 nm thick active layer, a PCE of 6.72% with a high FF of 67.8% is still obtained for FBT-DThDT-TT-H-based devices. The impressive results make FBT-DThDT-TT a promising candidate for applications of large-scale solution-processable PSCs.

Graphical abstract: An extended π-conjugated area of electron-donating units in D–A structured polymers towards high-mobility field-effect transistors and highly efficient polymer solar cells

Supplementary files

Article information

Article type
Communication
Submitted
25 Jan 2017
Accepted
21 Feb 2017
First published
21 Feb 2017

J. Mater. Chem. C, 2017,5, 2786-2793

An extended π-conjugated area of electron-donating units in D–A structured polymers towards high-mobility field-effect transistors and highly efficient polymer solar cells

P. Cai, Z. Chen, L. Zhang, J. Chen and Y. Cao, J. Mater. Chem. C, 2017, 5, 2786 DOI: 10.1039/C7TC00428A

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