All-gas-phase synthesis of amino-functionalized UiO-66 thin films

Abstract

Thin films of metal-organic frameworks (MOFs) prepared using all-gas-phase techniques such as atomic/molecular layer deposition (ALD/MLD) are emerging due to their potential for enabling suitable applications. Their high and specific porosity enables their use as membranes for separations and as a basis for sensors in microelectronics, provided that films can be made. The properties of such MOF materials can be tuned by choosing linker molecules that are functionalized with a variety of chemical groups. However, thin films of these functionalised MOFs have so far been prepared through wet based chemistries, which are difficult to combine with microelectronics and high aspect ratio structures. We here report on the thin film deposition of amino-functionalised UiO-66 through an all-gas-phase ALD/MLD process. By using amino-functionalised linkers, modulation by acetic acid to control the stoichiometry of the deposited film was no longer required, as opposed to the case in which unmodified terephthalic acid was used as a linker. The growth and properties of the films were characterised using an in situ quartz crystal microbalance (QCM), spectroscopic ellipsometry (SE), grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR) and other techniques to obtain information on their growth dynamics and physical properties.

MOF thin films with bi-aromatic linkers grown by molecular layer deposition

“…5a). This is similar to what was found for lms deposited with 2-amino-1,4-BDC, 23 and indicates that the acetic acid modulation is not needed in this system. However, this is not completely true.…”

“…The MLD technique can be used to make organic lms or hybrid organic-inorganic lms for use in a wide range of applications that are summarized in a review article by Meng et al 17 A few examples of MOF thin-lms made by using MLD have emerged in the recent literature, [18][19][20][21] such as the demonstration of UiO-66 growth, 22 and growth of a similar MOF structure with an amino-functionalized linker. 23 In the current work, we expand the repertory of MLD synthesis of Zr MOFs to also include 2,6-naphthalenedicarboxylate (2,6-NDC) and biphenyl-4,4 0 -dicarboxylate (BP-4,4 0 -DC) as linkers. This may enable synthesis of thin-lms of MOFstructures with slightly larger pores than those previously reported.…”

Organic electrode materials with solid-state battery technology

“…143 Most excitingly, the recent advances in the combined ALD/MLD technique have widened the repertoire of electrode materials from inorganic materials to cover also many organic electrode materials. 135,[144][145][146][147][148] Thin lms of the organic electrode and inorganic solid-electrolyte materials deposited from gaseous precursors on top of each other is in principle the simplest form of a microbattery, 109,149 andpotentiallyby moving from planar to three-dimensional substrates high footprint capacity can be achieved. 150 In addition, since the ALD/MLD fabricated thin-lm microbattery can be made without any additives it forms the simplest system where the interactions of the layers could in principle be studied in an electrochemical half-cell.…”

Atomic/molecular layer deposition and electrochemical performance of dilithium 2-aminoterephthalate

“…28 Steric hindrance of the amino group most likely plays a role here, in such a way that the different synthesis conditions could lead to different amino group arrangements. 32,33 The chemical bonding scheme in our Li 2 TP-NH 2 thin films was studied with FTIR spectroscopy. A comparison of the thinfilm spectrum to that of its TPA-NH 2 precursor confirms the disappearance of the characteristic carbonyl group (only seen for the acid precursor) and the appearance of the carboxyl feature upon the metal carboxylate bond formation (ESI Fig.…”