Issue 34, 2024

Overcoming the mobility penalty introduced by dipole disorder in small-molecule HTM films

Abstract

The importance of the hole-transport material (HTM) in perovskite solar cells (PSCs) is now very well-established, with state-of-the-art materials such as spiro-OMeTAD attracting significant attention in the last decade. The high cost of such materials still limits the commercialisation of these HTMs. To tackle this, the amide linker has recently been introduced into HTM systems viaEDOT-Amide-TPA, utilising condensation chemistry as a cheap and effective route to HTMs. EDOT-Amide-TPA is capable of a variety of intermolecular interactions such as dipole–dipole interactions and hydrogen bonding, both of which are beneficial for enhancing the film morphology and improving charge transport. However, the interplay between these different interactions is not trivial, and understanding how they affect each other is paramount to inform new HTM designs whilst minimising material waste. To date, studies investigating the combined effects of different intermolecular interactions within the HTL on the charge transport properties of these materials are lacking. Furthermore, dipole disorder within the film introduces a mobility ‘penalty’: mobility decreases with stronger overall dipole due to energetic disorder within the film, which hinders charge hopping. In this work, we investigate three amide-based HTM analogs with differing intermolecular interaction capabilities, and show that this penalty can be compensated by a preferentially increased dipole ordering, likely achieved through intermolecular hydrogen bonding. This effectively cancels out the dipole disorder while retaining the beneficial effects on the molecular packing. Our aim is that this work provides a good foundation for navigating the complex interplay between hydrogen bonding, dipole moments, conductivity, and film formation in small-molecule HTMs.

Graphical abstract: Overcoming the mobility penalty introduced by dipole disorder in small-molecule HTM films

Supplementary files

Article information

Article type
Paper
Submitted
09 Feb 2024
Accepted
25 Jul 2024
First published
25 Jul 2024
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2024,12, 22844-22858

Overcoming the mobility penalty introduced by dipole disorder in small-molecule HTM films

B. Vella, M. H. Fsadni, T. Pope, M. Giza, F. J. Angus, I. Shmarov, P. L. Lalaguna, M. Cariello, C. Wilson, M. Kadodwala, T. J. Penfold, P. Docampo and G. Cooke, J. Mater. Chem. A, 2024, 12, 22844 DOI: 10.1039/D4TA00956H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements