Composition-tuned metal-organic thin-film structures based on photoswitchable azobenzene by ALD/MLD

Aida Khayyami, Anish Philip, Jenna Multia, Maarit Karppinen

Research output: Contribution to journalArticleScientificpeer-review

71 Downloads (Pure)

Abstract

We demonstrate the fabrication of in-situ crystalline thin films of various azobenzene (AZO) based metal-organic structures using the atomic/molecular layer deposition (ALD/MLD) technique; these are highly intriguing materials as azobenzene is one of the prototype organic molecules experiencing photoisomerization. Our Li-, Ca and Fe-AZO thin films deposited from Li(thd) (thd = 2,2,6,6-tetramethyl-3,5-heptanedione), Ca(thd)2, FeCl3 and azobenzene-4,4'-dicarboxylic acid precursors in the temperature range of 250-360 °C exhibit metal-AZO structures not known from bulk samples. In all these structures, the AZO linker molecules are free to undergo the characteristic trans-cis photoisomerization reaction upon UV (360 nm) irradiation. However, this lowers the degree of crystallinity. To address the issue, we investigate hetero-organic structures where TPA (terephthalic acid) is used as another linker component together with AZO. This allows the trans-cis reaction of the AZO moieties to occur without compromising the film crystallinity. Finally, we demonstrate the growth of MOF-on-MOF type Ca-ADA@Ca-TPA thin films also showing the efficient photoisomerization reaction.

Original languageEnglish
Pages (from-to)11310–11316
Number of pages7
JournalDalton Transactions
Volume49
Issue number32
DOIs
Publication statusPublished - 28 Aug 2020
MoE publication typeA1 Journal article-refereed

Fingerprint Dive into the research topics of 'Composition-tuned metal-organic thin-film structures based on photoswitchable azobenzene by ALD/MLD'. Together they form a unique fingerprint.

Cite this