Perspectives on Thin Molecular Organic Films

Abstract

The engineering versatility of molecular organic materials, together with their attractive electronic, magnetic, and optical properties, have triggered their preparation as thin films in the last years. Although the interactions between molecules and inorganic substrates are rather weak (van der Waals, hydrogen bonding, etc.), the crystallographic phase, the type and degree of orientation, and the morphology of the resulting films critically depend on the interface and the kinetics of growth. The control of the structure and morphology of the films is thus essential when envisioning practical applications. The relevance of interfaces in the growth and doping of films is discussed, and the phenomenology of polymorphism is explored. Additional issues such as the mechanical properties are also addressed. The figure, showing a scanning tunneling microscopy image of a monolayer of bis(ethylenedithio)‐tetrathiafulvalene on a Au(111) substrate, illustrates the interface issue.

Adsorption of n-butyl-substituted tetrathiafulvalene dodecanethiol on gold

“…Several studies have been made on SAMs systems with tetrathiafulvalenes [6][7][8][9][10][11][12]. SAMs with TTFs have been suggested for different possible applications as organic electronic thin-film devices [13,14].…”

Self‐Waveguided Photoemission and Lasing of Organic Crystalline Wires Obtained by an Improved Expitaxial Growth Method

“…Therefore, it is promised that organic devices such as thin film transistors, light-emitting diodes and solid-state lasers based on organic materials attain higher performance. [1,[3][4][5][6] Furthermore, the ability to prepare highly controlled molecular alignments in nano-space will lead to organic nanotechnology in future. In this paper we describe a preparation of highly oriented molecular crystalline wires of α, ω-di(biphenyl)-terthiophene (BP3T; see self-waveguided photoemissions with a high internal quantum efficiency and self-cavity lasing.…”

Electrical and optical properties of (PPh4)2[Fe(CN)5NO] non-crystalline thin films prepared with the vacuum thermal evaporation technique

“…Over the last few years, there has been an increasing number of reports regarding the formation of molecular materials based on organic and organometallic derivatives with electronic or optoelectronic properties [1]. It may be difficult to envision a technological breakthrough while using them in their usual, single-crystalline form, but the thin-film production of such materials offers an attractive alternative [2][3][4][5][6][7].…”

“…Recent research work has been oriented to the formation and characterization of molecular-material thin films with probable photonic, optoelectronic or electronic-device applications [8,9]. It is well known that the properties of such thin films strongly depend on their microstructures [1,8]. A regular stacking of molecules, such as is found in molecular materials, may permit the formation of semiconducting, conducting or superconducting thin films.…”

“…A regular stacking of molecules, such as is found in molecular materials, may permit the formation of semiconducting, conducting or superconducting thin films. Therefore, in order to describe the relationship between the physical configuration and the electrical properties of the thin films, it is necessary to produce such systems with a welldefined microstructure [1][2][3][4][5][6][7][8][9].…”