Thin films organic molecules

Polymer LEDs are similar to thin film organic molecular LEDs first reported in 1987 17). Organic molecular LEDs utilize thin films of small organic molecules rather than polymer films as the light-emitting layer. The films of small organic molecules are undoped and have electronic properties comparable to the polymer films used in polymer LEDs. In general, the device physics of polymer LEDs is... 

Reactions on the surface are interesting. The adsorptions of unsaturated organic molecules on the surface provide a means for fabricating well-ordered monolayer films. Thin film organic layers can be used for diverse applications such as chemical and biological sensors, computer displays, and molecular electronics. 

As a class of n-type organic semiconductors, PBI derivatives have received considerable attention for a variety of applications [312, 313], for example, for organic or polymer light-emitting diodes (OLEDs and PLEDs) [314, 315], thin-film organic field-effect transistors (OFETs) [316, 317], solar cells [318, 319], and liquid crystals [320]. They are also interesting candidates for single-molecule device applications, such as sensors [321], molecular wires [322], or transistors [141]. 

On the other hand, miscibility is, in one sense, one of the characteristic properties in liquid crystals. Miscibility in liquid crystals is a well-known macroscopic property where one can see two mesogens exhibiting a thermodynamically identical liquid crystalline phase are mixed to show its phase at arbitrary component ratio. This has already been applied to liquid crystals for LCDs to control some properties such as temperature range of nematic phase. A diversity of functional properties such as temperature range, anisotropic electrical permittivity, viscosity etc. can be controlled in nematic blends and non-mesogenic molecules also can be a component which contributes to the resultant properties as they behave like a solute in liquid solution. However, charge transport property has not yet been well studied in terms of molecular blends with liquid crystalline materials, while thin film organic photovoltaics have been so extensively studied in recent years as molecular blends. 

Low temperature sol-gel technology is promising approach for preparation of modified with organic molecules silica (SG) thin films. Such films are perspective as sensitive elements of optical sensors. Incorporation of polyelectrolytes into SG sol gives the possibility to obtain composite films with ion-exchange properties. The addition of non-ionic surfactants as template agents into SG sol results formation of ordered mechanically stable materials with tunable pore size. 

STM has, however, not only been applied to metals and semiconductors, but also to a wide variety of organic and biological systems, like thin films on conducting substrates [5.15, 5.16] as well as protein and DNA molecules [5.43-5.46]. 

To date, most small molecule-based OLEDs are prepared by vapor deposition of the metal-organic light-emitting molecules. Such molecules must, therefore, be thermally stable, highly fluorescent (in the solid state), form thin films on vacuum deposition, and be capable of transporting electrons. These properties limit the number of metal coordination compounds that can be used in OLED fabrication. 

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