Electrically active organic and polymeric materials for thin-film-transistor technologies

Abstract

Organic and polymeric materzials have seen a tremendous growth in research in the last five years as potential electroactive elements in thin-film-transistor (TF T) applications. These are driven by the increasing interest in flat-panel-display applications, for which organic and polymeric materials offer strong promise in terms of properties, processability, cost, and compatibility with eventual lightweight, flexible plastic displays. In this review we summarize the current status of our knowledge on the science of these organic and polymeric semiconducting materials. Most of these are based on linear thiophenes, especially a-hexathienyl, which has elicited by far the most attention. Mobility values in the 10 22 -10 21 cm 2 ͞Vs and especially source-drain current on͞off ratios of up to 10 6 make this a highly promising potential alternative to amorphous silicon. Other thienyl compounds are also discussed, as are polymeric analogues. A brief discussion of technological potential, limitations, and problems that need to be overcome is given at the end.

The Nature of Interchain Excitations in Conjugated Polymers: Spatially-Varying Interfacial Solvatochromism of Annealed MEH-PPV Films Studied by Near-Field Scanning Optical Microscopy (NSOM)

“…A much larger optical signal level variation (g20%) is observed in panel c, under the same conditions for which the topographical data in Figure 3d show the film to be swollen with the solvent. The field of view in each panel is (30 µm) 2 . These far-field measurements demonstrate that the domains observed in the NSOM studies of MEH-PPV films, such as those in Figure 7d, are observable due to the very shallow depth of NSOM.…”

“…The integrated PL intensities (integrated from 535 to 900 nm) for all regions under all of the applied liquids were identical to (1%, but there is ∼40% less total integrated intensity at wavelengths g700 nm from regions that show the solvatochromic red shift. Part b shows the topography of a typical (10 µm) 2 -Shifting (e.g., Figure 6a) and Solvatochromically Red-Shifting Regions (e.g., Figure 6b) Table 2 shows that the calculated magnitude of the change in dipole increases by ∼15% as p s is increased from 4 to 5. The calculated values for ∆µ e increase by a factor of 2 when the radius of the emitter is increased from R ) 2a ) 5 to R ) 2a ) 8 Å, as can be seen in Table 3.…”

Recent advances in organic field effect transistors

“…We include representative examples from various classes of organic semiconductors, fabrication processes, and OTFT designs. Some older papers that, in the authors' opinion, played a pivotal role in shaping the OTFT field are also reviewed briefly, but the reader is encouraged to look up a number of previously published review papers that cover that period in more detail [14][15][16][17][18][19][20][21][22][23][24][25]. In addition, reported results from single crystal organic field effect transistors will be used to estimate the upper limits of mobility for the various organic semiconductors and to gain a better understanding of the underlying device physics.…”

Electronic structure of thiophenes and phtalocyanines

“…[1][2][3] Since the first report in 1987, 4 the performance of organic FET's has continuously improved and now they can compete with other conventional thin-film transistors ͑TFT's͒ such as amorphous silicon devices. For instance, on-off ratios of organic FET's are in the 10 9 range, whereas those of a-Si:HTFT's are limited to 10 6 .…”