Thin electroluminescent polymers

The apphcation of a high electric field across a thin conjugated polymer film has shown the materials to be electroluminescent (216—218). Until recentiy the development of electroluminescent displays has been confined to the use of inorganic semiconductors and a limited number of small molecule dyes as the emitter materials. Expansion to the broad array of conjugated polymers available gives advantages in control of emission frequency (color) and facihty in device fabrication as a result of the ease of processibiUty of soluble polymers (see Chromogenic materials,electrochromic). 

Thin Films of Electroluminescent Polymers 335 Electronic Eneigy Structure 336 Optical Properties 336 Electrical Transport Properties 338... 

A thin film ( 100 nm) of a PPV derivative is sandwiched between two electrodes supported on a solid substrate, such as glass, a flexible plastic substrate, such as poly(propylene), or even a thin film of aluminium, see Figure 6.1. The device substrate provides the mechanical support to the anode, electroluminescent polymer layer and the cathode. The anode is transparent in... 

M. Cheng, Y. Xiao, W. L. Yu, Z. K. Chen, Y. H. Lai, and W. Huang. Synthesis and characterization of a cyano-substituted electroluminescent polymer with well-defined conjugation length. Thin Solid Films, 363(1-2) 110-113, March 2000. 

Scurlock RD, Wang B, Ogilby PR, Sheats JR, Clough RL (1995) Singlet oxygen as a reactive intermediate in the photodegradation of an electroluminescent polymer. J Am Chem Soc 117 10194-10202 Torsi L, Dodabalapur A, Sabbatini L, Zambonon PG (2000) Multi-parameter gas sensors based on organic thin-film-transistors. Sens Actuators B 67 312-316... 

Another recently discovered form of epitaxy is graphoepitaxy (Geis et al. 1979). Here a non-crystalline substrate (often the heat-resistant polymer polyi-mide, with or without a very thin metallic coating) is scored with grooves or pyramidal depressions the crystalline film deposited on such a substrate can have a sharp texture induced by the geometrical patterns. More recently, this has been tried out as an inexpensive way (because there is no need for a monocrystalline substrate) of preparing oriented ZnS films for electroluminescent devices (Kanata et al. 1988). 

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