Interfacial Organic Layers for Chemical Stability and Crystalline Ordering of Thiophene and Carboxyl Films on a Metal Surface

Abstract

Organic-based devices require multicomponent, multilayer architectures consisting of functional molecules that may be chemically unstable at a metal interface. In this work, we demonstrate that an interfacial organic layer (IOL) provides chemical stability at and above room temperature, while also achieving desired crystalline ordering of the functionalized organic layer. As the IOL decouples organic species from direct interactions with the metal, new structural motifs become available that are not otherwise observed, yielding the first submolecular resolution imaging of phenylthiophene stacking at a surface. We studied self-organized layers comprising two classes of functional groups, carboxylic acids and thiophenes, which have applications in organic electronics but are each chemically unstable and structurally disordered when deposited directly onto the Cu(001) and other metal surfaces. The IOL strategy demonstrated here resolves these issues and broadens opportunities for organic thin films on metal surfaces in organic photovoltaic, organic semiconductor, catalyst, and other technologies.

Ultrathin ionic liquid films on metal surfaces: adsorption, growth, stability and exchange phenomena

“…In analogy to molecular exchange and preferential adsorption processes after sequential deposition of two different ILs on Ag(111) [81,82], exchange processes have also been reported for organic bilayers on metals involving porphyrins and related aromatic molecules [156][157][158][159][160][161][162][163][164]. These investigations highlight the importance of the strength of the organic-metal interaction and its correlation to the stability and arrangement in stacked multilayer architectures [156,161,162,[164][165][166][167][168][169][170]. Although combinations of porphyrins and ILs were already realized for catalysis [171] and dye-sensitized solar cell technologies [40,41], dedicated interface studies of porphyrin/IL hybrid systems are still missing.…”

A Deep Blue B,N-Doped Heptacene Emitter That Shows Both Thermally Activated Delayed Fluorescence and Delayed Fluorescence by Triplet–Triplet Annihilation

“…We next performed scanning tunneling microscopy (STM) measurements to study the self-assembly process of α-3BNOH on a Au(111) surface. The focus was on the first layer which, through templating and modification of chemical interactions, is critical for the growth of thin films. − Samples prepared at two different temperatures (RT and 343 K) and a range of concentrations were investigated. The STM images at submolecular resolution of layers prepared from solutions of α-3BNOH (Figure ) reveal a pronounced influence of concentration on the order of the layers as illustrated in Figure whereas no noticeable influence of the preparation temperature was observed.…”

Organic Multilayer Films Studied by Scanning Tunneling Microscopy

“…In the work by Skomski and Tait, an interfacial organic layer (IOL) with the capability of protecting and ordering organic overlayers, as well as self‐repair, was demonstrated . On top of the IOL, which was composed of the ML of terephthalic acid (TPA) deposited on Cu(001), functional carboxyl and thiophene species that were chemically unstable and disordered at the metal interface attained chemical stability and 2D crystalline order.…”