Fluorenyl Indoline as an Efficient Electron Donor for Concerted Companion Dyes: Enhanced Light-Harvesting and Photocurrent

Yingying Chen; Yunyu Tang; Jiazhi Zou; Kaiwen Zeng; Glib Baryshnikov; Chengjie Li; Yongshu Xie

doi:10.1021/acsami.1c12448

Fluorenyl Indoline as an Efficient Electron Donor for Concerted Companion Dyes: Enhanced Light-Harvesting and Photocurrent

ACS Appl Mater Interfaces. 2021 Oct 27;13(42):49828-49839. doi: 10.1021/acsami.1c12448. Epub 2021 Oct 12.

Authors

Yingying Chen¹, Yunyu Tang², Jiazhi Zou¹, Kaiwen Zeng¹, Glib Baryshnikov³, Chengjie Li¹, Yongshu Xie¹

Affiliations

¹ Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, P. R. China.
² East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Jungong 300, Shanghai 200090, P. R. China.
³ Department of Science and Technology, Laboratory of Organic Electronics, Linköping University, Norrköping SE-60174, Sweden.

PMID: 34641667
DOI: 10.1021/acsami.1c12448

Abstract

Concerted companion dyes (CC dyes) like XW61 have been demonstrated to be an effective platform for developing efficient DSSCs. However, the moderated phenothiazine-based electron donor in XW61 results in unsatisfactory J_sc. To address this problem, a stronger fluorenyl indoline-based electron donor has been used to construct porphyrin dye XW68 and organic dyes Y1-Y2. The stronger electron-donating character of the fluorenyl indoline unit leads to an enhanced J_sc value (20.48 mA·cm^-2) for the individual dye XW68. On this basis, CC dyes XW69-XW70-C8 have been designed and synthesized by combining the frameworks of Y1 and Y2 with XW68. The complementary absorption characters of the porphyrin and the organic dye moieties lead to panchromatic absorption with a strong light-harvesting capability from 350 to 700 nm and the onset wavelength extended to ca. 840 nm in the IPCE curves. As a result, excellent J_sc values have been achieved (>22 mA·cm^-2). In addition to the advantages of high J_sc, bulky octyl groups have been introduced into the donor of XW70-C8 to reduce dye aggregation and suppress charge recombination. Finally, a highest PCE of 11.1% with a satisfactory J_sc (22.25 mA·cm^-2) and an enhanced V_oc (750 mV) has been achieved upon coadsorption of XW70-C8 with CDCA. In addition, the CC dye XW70-C8-based solar cells exhibit excellent long-term photostability. These results provide an effective method for rationally improving the photovoltaic behavior, especially the J_sc of CC dyes, by introducing strong electron donor moieties with suitable substituents.

Keywords: coadsorption; concerted companion dyes; dye-sensitized solar cells; indoline; porphyrin.