Issue 23, 2024

Significant differences in photophysical and photovoltaic properties of flexible chain terminated homoleptic tris-Ir(iii) complexes

Abstract

Cyclometallated heavy metal complexes as photoactive materials have not received as much attention as pure organic/polymer counterparts in organic solar cells (OSCs). In this work, a novel homoleptic Ir(III) complex, tris(2-ethylhexyl 5′′-(benzo[d]thiazol-2-yl)-[2,2′:5′,2′′-terthiophene]-5-carboxylate) Ir(III) (ATBz3Ir), is presented for potential use in OSCs. Compared to hexyl-terminated TBz3Ir with the same main ligand backbone, ethylhexyl carboxylic ester-terminated ATBz3Ir exhibits significantly attenuated absorption at longer wavelengths of 400–600 nm. ATBz3Ir only shows phosphorescence peaking at 706 nm with a triplet lifetime of 280 ns in solution, which is dramatically different from the double modal profile for TBz3Ir with high-intensity fluorescence (564 nm/0.59 ns) and low-intensity phosphorescence (790 nm/174 ns). When employed as the third component for PM6:Y6 blended OSCs, ATBz3Ir and TBz3Ir exhibit opposite effects. The maximum power conversion efficiency (PCE) is improved from 15.14% for binary PM6:Y6 to 16.50% for PM6:ATBz3Ir:Y6 based ternary devices, while the PCE decreases to 14.49% for the PM6:TBz3Ir: Y6 device. The main reason could be attributed to the better miscibility between ATBz3Ir and the Y6 acceptor, which induces enhanced Y6-aggregation, and thus increased Y6-absorption, more efficient exciton dissociation, improved electron transport and reduced charge recombination. Similarly, an enhanced PCE was also achieved from 16.11% to 17.04% for other batches of PM6′:Y6′ and from 17.25% to 18.37% for PM6:L8-BO based ternary devices, respectively, which further support the efficiency of the third component of ATBz3Ir.

Graphical abstract: Significant differences in photophysical and photovoltaic properties of flexible chain terminated homoleptic tris-Ir(iii) complexes

Supplementary files

Article information

Article type
Paper
Submitted
18 اپریل 2024
Accepted
14 میٔ 2024
First published
15 میٔ 2024

J. Mater. Chem. C, 2024,12, 8334-8342

Significant differences in photophysical and photovoltaic properties of flexible chain terminated homoleptic tris-Ir(III) complexes

D. You, T. Yang, A. Zhou, S. Li, K. Lv, H. Ma, H. Zhong and Y. Tao, J. Mater. Chem. C, 2024, 12, 8334 DOI: 10.1039/D4TC01588F

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