Issue 20, 2025, Issue in Progress

Star-shaped small-molecule hole-transport materials for dopant-free perovskite solar cells

Abstract

Perovskite solar cells hold great potential for efficient photovoltaics, with hole-transporting materials being key to their success. We synthesized three new conjugated small-molecule HTMs—DPAMes-TT, TPA-TT, and PhFF-TT—and evaluated them in n–i–p PSCs. These molecules, featuring triphenylamine or trifluorobenzene cores, were analyzed in terms of their optical, electrochemical, thermal, and charge transport properties. DPAMes-TT and TPA-TT exhibited narrow bandgaps (2.66 eV and 2.61 eV), HOMO levels well-aligned with MAPbI3's valence band (−5.28 eV and −5.30 eV vs. −5.4 eV), and high hole mobilities. In contrast, PhFF-TT with trifluorobenzene core had a wider bandgap (2.95 eV), a less favorable HOMO (−5.14 eV), and signs of J-aggregation, impairing charge transport. PSCs with DPAMes-TT delivered the highest efficiency (19.3%), outperforming TPA-TT (18.5%) and the PTAA reference (18.1%). PhFF-TT devices, however, reached only 12.6% limited by recombination and poor interface quality, as revealed by photoluminescence. Charge transport studies confirmed DPAMes-TT's superior hole extraction, while PhFF-TT suffered higher recombination losses. These findings show how molecular design shapes PSC performance, with amine-based HTMs like DPAMes-TT and TPA-TT excelling over trifluorobenzene-based HTMs.

Graphical abstract: Star-shaped small-molecule hole-transport materials for dopant-free perovskite solar cells

Supplementary files

Article information

Article type
Paper
Submitted
09 Apr 2025
Accepted
01 May 2025
First published
13 May 2025
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2025,15, 15763-15770

Star-shaped small-molecule hole-transport materials for dopant-free perovskite solar cells

I. V. Martynov, M. M. Agapitova, I. E. Kuznetsov, V. S. Volkov, M. Tepliakova, A. V. Akkuratov and A. V. Arsenin, RSC Adv., 2025, 15, 15763 DOI: 10.1039/D5RA02466H

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