Wet-processed n-type OTFTs utilizing highly-stable colloids of a perylene diimide derivative

Here we propose and demonstrate a new approach to wet-processed organic thin-film transistors utilizing highly-stable colloids of small molecular organic semiconductors prepared by laser ablation technique. Highly stable N,N′-ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C13) colloids of 0.1 wt% concentration were prepared successfully by laser ablation technique in acetonitrile. Mean particle size of the prepared PTCDI-C13 colloid measured by dynamic light scattering method was smaller than 50 nm which is also confirmed by a transmission electron microscope observation. By simple drop-casting of prepared PTCDI-C13 colloids, typical n-type OTFTs with good saturation properties were fabricated successfully. The highest electron mobility was 1.1 × 10−3 cm2/Vs and increased up to 0.027 cm2/Vs by post-annealing treatment.ArticleORGANIC ELECTRONICS. 14(1):19-25 (2013)journal articl

Comparative Study of Soluble Naphthalene Diimide Derivatives Bearing Long Alkyl Chains as n-type Organic Thin-Film Transistor Materials

ArticleORGANIC ELECTRONICS. 14(2):516-522 (2013)journal articl

Thermal treatment effects on N-alkyl perylene diimide thin-film transistors with different alkyl chain

The authors report that thermal treatment effect on various N,N'-dialkyl-3,4,9,10-perylene tetracarbxylic diimides [PTCDI-Cn, alkyl-dodecyl (n = 12), butadecyl (n = 14), octadecyl (n = 18)] thin-film transistors (TFTs) depends on the substituted alkyl chain length. It is clearly demonstrated that there are two kinds of molecular movements during the thermal treatment on PTCDI films; molecular rearrangement in the same layer and molecular migration from the lower layer to the upper layer. The former is directly related to the grain growth and can be controllable by applying an external electric field. The latter is also related not only to the grain growth but also to the formation of cracks between grains. These two movements show opposite dependence on the alkyl chain length during the thermal treatment; the former is more active in longer alkyl chain, but the latter in shorter one. However, they also have opposite effect to TFT performance, and PTCDI films with longer alkyl chains have great advantage on TFT performance for the thermal treatment. Consequently, PTCDI-C18 TFTs show the highest electron mobility as large as 1.2 cm(2)/V s after the thermal treatment at 140 degrees C. (C) 2010 American Institute of Physics. [doi:10.1063/1.3525997]ArticleJOURNAL OF APPLIED PHYSICS. 108(12):124512 (2010)journal articl

Effects of the Environmental Factors upon the Differentiation and Development of Fruit Buds of the Peach Trees

1. The development of peach fruit buds collected simultaneously from twenty different regions in Japan was classified into three groups according to the climatic conditions, in spite of the differences of tree age and methods of cultivation. It was related with the mean temperature in June, July, and August in 1957. It was also known that about 900 degrees C of heat summations above 10 degrees C from the time of sprouting in April to the time of fruit bud differentiation in the peach in various regions was required. 2. As the results of temperature treatments, high day and night temperatures markedly prevented the fruit bud formation, and also high night temperature reduced the number of fruit buds. 3. The time of differentiation of fruit bud in the peach does not definitely respond to light duration, but, under short photoperiods the number of fruit buds was considerably reduced. The shading of the peach trees greatly reduced the fruit bud formation, and with the severe shading the peach tree finally died. It indicated that in the interior of dense, unpruned trees, the flower formation may be greatly prevented by the low intensity of light. 4. The differentiation and development of fruit buds were stimulated under dry conditions of the soil at the early stage of growth, and they were greatly reduced, if the soil conditions were either extremely dry or wet throughout the growing season. 5. The excessive application of inorganic nitrogen fertilizer to young peach trees definitely delayed the differentiation and formation of fruit bud, while the application of phosphorus fertilizer considerably increased fruit bud formation. 6. The complete defoliation at the early stages of growing season entirely prevented the formation of fruit bud. Some buds were destroyed, and others were stimulated to sprout the secondary shoot. The similar effects, though less severe, were found also in plots where three-fourths leaves were removed

Antral Somatostatin Contents and Acidity of Gastric Juice in Normal Subjects and Patients with Duodenal Ulcer

The antral somatostatin contents were investigated in biopsy specimens of the antrum from normal subjects and patients with duodenal ulcer. There was good correlation (r=0.77044) between antral somatostatin contents and maximal acidity in normal subjects, but the correlation between antral somatostatin contents and maximal acid output was not significant (r=0.254367). This result may indicate that antral somatostatin content is regulated by intragastric pH in normal subjects. On the other hands, no correlation was observed between antral somatostatin contents and acidity or acid output in patients with duodenal ulcer. Therefore the impaired regulation of acid on antral somatostatin contents could be one of the important factors in the pathogenesis of duodenal ulcer disease

Thermal treatment effects on N-alkyl perylene diimide thin-film transistors with different alkyl chain

The authors report that thermal treatment effect on various N,N'-dialkyl-3,4,9,10-perylene tetracarbxylic diimides [PTCDI-Cn, alkyl-dodecyl (n = 12), butadecyl (n = 14), octadecyl (n = 18)] thin-film transistors (TFTs) depends on the substituted alkyl chain length. It is clearly demonstrated that there are two kinds of molecular movements during the thermal treatment on PTCDI films; molecular rearrangement in the same layer and molecular migration from the lower layer to the upper layer. The former is directly related to the grain growth and can be controllable by applying an external electric field. The latter is also related not only to the grain growth but also to the formation of cracks between grains. These two movements show opposite dependence on the alkyl chain length during the thermal treatment; the former is more active in longer alkyl chain, but the latter in shorter one. However, they also have opposite effect to TFT performance, and PTCDI films with longer alkyl chains have great advantage on TFT performance for the thermal treatment. Consequently, PTCDI-C18 TFTs show the highest electron mobility as large as 1.2 cm(2)/V s after the thermal treatment at 140 degrees C. (C) 2010 American Institute of Physics. [doi:10.1063/1.3525997]ArticleJOURNAL OF APPLIED PHYSICS. 108(12):124512 (2010)journal articl