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A new understanding and a promising solution for the stability of organic transistors and circuits are presented. The electrodes are demonstrated to play an unexpectedly important role on the device stability. Au electrodes exert a detrimental effect on the device stability, while the overall device stability of p‐/n‐type transistors and complementary inverter circuits is improved significantly by using conducting polypyrrole (PPY) electrodes.

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Si, "A1, and 'H MAS NMR studies of partially carbonated mature ordinary portland cement (OPC) and tricalcium silicate (C,S) pastes have been carried out. The water-to-solid ratios ( w / s ) have been varied between 0 and 1 at hydration temperatures of 23" and 90°C. Various Q" units with n = 0, 1, 2, 3, and 4, and a Q3 (1Al) group have been identified using ''Si NMR. Cross-polarization experiments, in addition, have made it possible to assign the OH groups. Two types of fourfold-and one type of sixfold-coordinated aluminum have been distinguished using 27Al NMR. In C3S pastes for w / s > 0.7, progressive carbonation leads to a nearly perfect three-dimensional network consisting of Q3 and Q4 only. In contrast, in OPC pastes only about 40% of the highly polymerized silicate units are formed, partially copolymerized with ,410, tetrahedra.

Chemical reaction steps have been monitored by 29Si NMR in the liquid stage of a sol‐gel process during the preparation of glasses in the ternary system 65SiO2—20TiO2—15ZrO2 from the corresponding alkoxides. Most of the recorded signals could be assigned to monomer species and larger building units, and the time evolution of the spectra of the two‐component systems Si/Ti and Si/Zr has been correlated with that of the pure starting material TEOS. No evidence has been found for the formation of ≡Si —O—Ti≡ or ≡ Si —O —Zr≡ bonds in the early polymerization. Quantitative considerations of the 29Si spectra have revealed the main condensation pathways in the Si/Ti system. 29Si MAS NMR yields, as a preliminary result, a higher branching of the network when passing from the dried gel to the annealed gel‐glas