Low cost triazatruxene hole transporting material for >20% efficiency perovskite solar cells

Connell, A; Zhiping, W; Lin, Y-H; Greenwood, PC; Wiles, AA; Jones, EW; Furnell, L; Anthony, RVE; Kershaw, CP; Cooke, G; Snaith, HJ; Holliman, PJ

Abstract

Organic hole-transporting materials (HTM) have shown excellent ability in achieving high efficiency
perovskite solar cells. However, their high cost significantly limits their applications in scaling-up
perovskite solar cells. Here, we report an efficient, low-cost HTM, called TAT-tBuSty, comprising a
central triazatruxene moiety with 3 terminal tert-butoxy styrene groups and 3 hexyl side chains on the
indole nitrogen. For the first time, we use an inexpensive liquid precursor to attach the donor ligand to
the molecule. This enables purification of the HTM using a silica plug and recrystallization without the
need for complicated column chromatography, which is typically required to purify solid-precursorprepared
HTMs. We estimate that the cost for the purified TAT-tBuSty is $69.90 g�1, which is 35%
cheaper than the widely-used 2,207,70-tetrakis-(N,N-di-p-methoxyphenyl-amine)-9,90-spirobifluorene
(spiro-OMeTAD; ca. $112.05 g�1). Using this low-cost TAT-tBuSty as the HTM in a caesium-formamidinium
mixed-cation perovskite solar cell, we have successfully achieved a champion power conversion efficiency
(PCE) of 20.3% (19.4% stabilized efficiency), which is comparable to the efficiency of devices using the
reference spiro-OMeTAD HTM. Our work is crucial for up-scaling of next-generation high-performance
metal-halide perovskite solar cells.

Citation

Connell, A., Zhiping, W., Lin, Y., Greenwood, P., Wiles, A., Jones, E., …Holliman, P. (2019). Low cost triazatruxene hole transporting material for >20% efficiency perovskite solar cells. Journal of Materials Chemistry C, 7(18), 5235-5243. https://doi.org/10.1039/c8tc04231d

• Journal Article Type: Article
• Acceptance Date: Nov 7, 2018
• Online Publication Date: Nov 15, 2018
• Publication Date: Jan 1, 2019
• Deposit Date: Apr 20, 2020
• Journal: Journal of Materials Chemistry C
• Print ISSN: 2050-7526
• Electronic ISSN: 2050-7534
• Publisher: Royal Society of Chemistry
• Volume: 7
• Issue: 18
• Pages: 5235-5243
• DOI: https://doi.org/10.1039/c8tc04231d
• Publisher URL: https://doi.org/10.1039/C8TC04231D
• Related Public URLs: http://pubs.rsc.org/en/journals/journalissues/tc#!recentarticles&all
• Additional Information: Access Information : Author Accepted Manuscript available at: http://eprints.gla.ac.uk/173162/; Funders : Engineering and Physical Sciences Research Council (EPSRC); Projects : EPSRC-SPACE modules; Grant Number: EP/M015254/1