A 5.8‐in. phosphorescent color AMOLED display fabricated by ink‐jet printing on plastic substrate

Abstract— A flexible phosphorescent color active‐matrix organic light‐emitting‐diode (AMOLED) display on a plastic substrate has been fabricated. Phosphorescent polymer materials are used for the emitting layer, which is patterned using ink‐jet printing. A mixed solvent system with a high‐viscosity solvent is used for ink formulation to obtain jetting reliability. The effects of evaporation and the baking condition on the film profile and OLED performances were investigated. An organic thin‐film‐transistor (OTFT) backplane, fabricated using pentacene, is used to drive the OLEDs. The OTFT exhibited a current on/off ratio of 10⁶ and a mobility of 0.1 cm²/V‐sec. Color moving images were successfully shown on the fabricated display.     

Integrated circuits using fully solution-processed organic TFT devices with printed silver electrodes

We have demonstrated fully solution-processed inverter, NAND and NOR circuits using pseudo-CMOS logic and p-type organic TFT devices with printed electrodes that were fabricated using ink-jet printed silver nanoparticle inks at low temperatures. In order to optimize the gate electrode profiles, we thoroughly assessed the surface wettability of the silver nanoparticle inks. The pseudo-CMOS inverter circuit exhibited exceptional switching characteristics with a high signal gain of 34 at a supply voltage of 20 V. The NAND and NOR circuits also exhibited excellent logic characteristics, whereby the switching voltage was approximately V_DD/2 with a high noise margin and short delay time of 12.5 ms.     

Reduced contact resistance and highly stable operation in polymer thin-film transistor with aqueous MoOx solution contact treatment

We report on a newly developed solution process using MoO₃ for reducing source and drain (S/D) electrodes in organic thin-film transistor (TFT). By taking advantage of the difference in surface wettability between the gate dielectric layer and the S/D electrodes, the electrode treatment using the MoO_x solution was applied to polymer TFT with short channel lengths less than 10 μm. The contact resistance was noticeably reduced at the interface of the S/D electrodes in a polymer TFT using a pBTTT-C16. Furthermore, the field effect mobility for this TFT was enhanced from 0.03 to 0.1 cm²/V s. Most notably, the threshold voltage (V_th) shift under gated bias stress was less than 0.2 V after 10⁵ s, which is comparable to that of conventional poly crystalline Si TFT.     

Catalytic activity of pitch-based activated carbon fiber of large surface area heat-treated at high temperature and its regeneration for NO–NH3 reaction at ambient temperatures

The catalytic activity of a pitch-based activated carbon fiber (ACF) of very large surface area (OG-20A) was studied for NO–NH₃ reaction in a flow reactor at ambient temperatures. The ACF exhibited the highest activity in wet as well as dry gas among heat-treated ACFs so far examined by the present authors. The calcination at 1100°C was essential to exhibit the highest activity especially in wet gas. Although high humidity always retarded the reaction very markedly, its retardation was very much emphasized against NO of low concentration around 10 ppm. Sufficient amount of OG-20A-H1100 (3 g) allowed complete removal of 10–200 ppm NO by reduction and adsorption for initial 6 h even at least in wet gas at 25–30°C depending on NO concentration. The removal conversion decreased gradually for several hours following to the stationary one. The reactivity of adsorbed NO and NH₃ was examined in air to regenerate the period of complete NO removal over the ACF. The regeneration at 30°C was found optimum after the removal reaction at 25 or 30°C to provide the same period of complete removal by 3 h, leaking minimum amounts of adsorbed NO and NH₃. A higher reaction temperature of 35°C shortened the period of complete NO removal, and the successive regeneration at 30°C by 3 h failed in the complete NO removal in the second run. Oxygen appears necessary to regenerate the activity through enhancing the reaction of adsorbed NO and NH₃. NH₃ in the regeneration gas appears to inhibit the reaction of adsorbed species, increasing NH₃ leak.     

线性预测编码(LPC)技术及其在音频文件上的应用

介绍了线性预测编码 ( L PC)技术原理和音频文件 ,尤其是波形音频文件格式 ,并且讨论了 L PC技术在音频文件上的应用 ,同时给出了 L PC处理 WAVE文件流程图和 WAVE文件恢复流程图。     

Development of a new type of corrosive wear tester

A new type of corrosive wear tester has been developed, on which both static and transient corrosive wear tests can be performed. By combining the tester with an electrochemical measuring system and a dynamic strain gauge, studies can be done in fields such as polarisation curve measurement under conditions of corrosive wear, surface state and wear coefficient measurement, and dynamic observations of current under static potential, as well as the study of surface film rupture and recovery. Leakage of the solution was considered throughout the design, and was addressed by avoiding passing the rotating shaft through the electrolytic cell.     

Structural and electrical properties of plasma-deposited silicon nitride from SiH4-N2 gas mixture

Plasma-deposited silicon nitride films were produced from SiH₄-N₂ gas mixture. Their composition, chemical bonds, and electrical properties were investigated by varying the deposition conditions. The silicon nitride films from SiH₄-N₂ gas mixture exhibit (i) less hydrogen, (ii) higher thermal endurance, (iii) higher density, and (iv) smaller etching rate than those of the films deposited from SiH₄, and NH₃ gas mixture. These results can be partly attributed to lower hydrogen concentration. As the Si/N ratio approaches the stoichiometric value, 0.75, the resistivity and the breakdown strength are increased. They are 10¹⁵Ωcm and 9MV/cm, respectively, at Si/N≃0.85. Interface state density between silicon and silicon nitride layers is as low as 1& #x223C; 5xl0¹¹cm⁻² eV⁻¹. On leave from The Northwest Telecommunication Engineering Institute, Xi’an, The People’s Republic of China.     

Recombination dynamics of localized excitons in self-formed InGaN quantum dots

The dynamic behavior of radiative recombination has been assessed in the InGaN-based purple, blue and green light emitting diodes (LEDs), as well as in purple laser diode (LD) components by means of time-resolved electroluminescence (TREL) and time-resolved photoluminescence (TRPL) spectroscopy. It was found that excitons localized at deep trap centers play an important role in the recombination process. Microstructural analysis suggests that these centers originate from the In-rich regions, acting as quantum dots which are self-formed within the wells. The radiative lifetime of localized excitons in the LD structure was almost constant at 6 ns in the temperature range between 20 and 200 K, indicating the zero-dimensional feature of excitons.     

MBE growth and properties of GaN and AlxGa1−xN on GaN/SiC substrates

The growth of GaN and AlGaN by molecular beam epitaxy (MBE) has been studied using GaN/SiC substrates. The GaN/SiC substrates consisted of ∼3 μm thick GaN buffer layers grown on 6H-SiC wafers by metalorganic vapor phase epitaxy (MOVPE) at Crée Research, Inc. The MBE-grown GaN films exhibit excellent structural and optical properties—comparable to the best GaN grown by MOVPE. Al_xGa_1−xN films (x ∼ 0.06-0.08) and Al_xGa_1−xN/GaN multi-quantum-well structures which display good optical properties were also grown by MBE on GaN/SiC substrates.