Multiple time constant modelling of a printed conducting polymer electrode

Constant phase elements (CPE) are routinely used to describe the frequency response of electrochemical systems. However, this approach is often scientifically unsatisfactory because the physical origin of the phase is unclear. Here we observe CPE-like behaviour in a conducting polymer poly(3,4-ethylenedioxythiophene)/poly(styrene-4-sulfonate) (PEDOT:PSS) film that was inkjet printed onto paper to form a flexible electrochemical double layer capacitor electrode. We show that the response of the electrochemically active film can also be described using a physical model with multiple parallel finite RC (resistor–capacitor) transmission lines whose lengths and time constants are determined by the distribution of the measured film thickness. The modeled volumetric capacitance and ionic conductivity match those determined experimentally, suggesting that the physical origin of the constant phase response is a distribution of mass transport limited time constants.     

Inkjet printed chalcopyrite CuInxGa1−xSe2 thin film solar cells

In this paper, we report a novel approach for the fabrication of chalcopyrite CuIn_xGa_1−xSe₂ thin film solar cells by inkjet printing. The short circuit current (J_sc), open circuit voltage (V_oc), fill factor (FF), and total area power conversion efficiency (η) of the device are 29.78 mA/cm², 386 mV, 0.44%, and 5.04%, respectively. Inkjet printing at atmospheric environment offers an opportunity for the direct patterning of absorber materials at large scale. This provides a potential cost advantage over conventional fabrication process that involves sequential deposition, patterning, and etching of selected materials. In addition, inkjet printing increases the raw material utilization ratio compared to more wasteful vacuum-based deposition techniques.     

Air stable complementary polymer circuits fabricated in ambient condition by inkjet printing

Air stable complementary polymer inverters were demonstrated by inkjet printing of both top-gate electrodes and the semiconductors in ambient conditions. The p-type and n-type polymer semiconductors were also thermally annealed in ambient conditions after printing. The good performance of circuits in ambient condition shows that the transistors are not only air-stable in term of ambient humidity and oxygen, but also inert to ion migration through dielectrics from the printed gate. The result obtained here has further confirmed the feasibility of fabrication of low-cost polymer complementary circuits in a practical environment.     

Performance improvement of a drop-on-demand inkjet printhead using an optimization-based feedforward control method

The printing quality delivered by a drop-on-demand (DoD) inkjet printhead is limited due to the residual oscillations in the ink channel. The maximal jetting frequency of a DoD inkjet printhead can be increased by quickly damping the residual oscillations and by bringing in this way the ink channel to rest after jetting the ink drop. This paper proposes an optimization-based method to design the input actuation waveform for the piezo actuator in order to improve the damping of the residual oscillations. A discrete-time transfer function derived from the narrow-gap model is used to predict the response of the ink channel under the application of the piezo input. Simulation and experimental results are presented to show the applicability of the proposed method.     

Multi-dimensional data registration CMOS/MEMS integrated inkjet printhead

This paper describes our work aimed at developing an integrated multi-dimensional thermal inkjet (TIJ) printhead with data registration CMOS de-multiplexer utilizing bulk micromachining technology (MEMS). In this experiment, we developed a new structural design for chips used in inkjet printheads. We designed a thermal inkjet device, whose dimensions could be adjusted to optimize drop generation performance. The energy conversion device and accompanying system were based on an integrated driver head with the performance of a high-frequency, picoliter drop inkjet. The inkjet featured a smart CMOS circuit including D Flip-Flops signal processes along with bi-directional data transfer and 12 V power amplifiers in a printhead chip. All of the jets of the printhead were controlled by very few input lines, a pulse shape (ENABLE), a data line (DATA), a bit shift clock (BIT SHIFT), a state clearing pulse, 5-volt supply for the logic devices, a higher voltage for energizing the heater resisters, and a ground line. The fabricated backside etching of the thermal inkjet (TIJ) printhead was measured by open pool and closed pool systems. The starting voltage was measured at 6.5 V, and its lifespan was 1.5 × 10⁸.     

Modulation of surface solubility and wettability for high-performance inkjet-printed organic transistors

The surface solubility and wettability of photosensitive layers of polystyrene (PS) were engineered to evaluate its effect on the crystalline microstructure and film morphology of inkjet-printed 6,13-bis(triisopropylsiylethynyl) pentacene (TIPS-pentacene). UV exposure proved to be a simple and effective method for modulating the solubility of PS films with controllable crosslinking. As compared with the untreated PS film, the film morphology of the printed semiconductor on the UV-irradiated crosslinked PS films was significantly optimized. The optimal degree of crosslinking and solubility of the PS film were achieved by UV irradiation at a dose of 0.417 J cm⁻². Field-effect transistors fabricated using well-organized crystals on the optimal crosslinked PS film exhibited a maximum mobility of 0.48 cm² V⁻¹ s⁻¹ and an average value of 0.19 cm² V⁻¹ s⁻¹. The performance is clearly superior to that of devices prepared on a pristine PS film (0.02 cm² V⁻¹ s⁻¹).     

Optimizing the primary particle size distributions of pressurized metered dose inhalers by using inkjet spray drying for targeting desired regions of the lungs

Conventional suspension pressurized metered dose inhalers (pMDIs) suffer not only from delivering small amounts of a drug to the lungs, but also the inhaled dose scatters all over the lung regions. This results in much less of the desired dose being delivered to regions of the lungs. This study aimed to improve the aerosol performance of suspension pMDIs by producing primary particles with narrow size distributions. Inkjet spray drying was used to produce respirable particles of salbutamol sulfate. The Next Generation Impactor (NGI) was used to determine the aerosol particle size distribution and fine particle fraction (FPF). Furthermore, oropharyngeal models were used with the NGI to compare the aerosol performances of a pMDI with monodisperse primary particles and a conventional pMDI. Monodisperse primary particles in pMDIs showed significantly narrower aerosol particle size distributions than pMDIs containing polydisperse primary particles. Monodisperse pMDIs showed aerosol deposition on a single stage of the NGI as high as 41.75?±?5.76%, while this was 29.37?±?6.79% for a polydisperse pMDI. Narrow size distribution was crucial to achieve a high FPF (49.31?±?8.16%) for primary particles greater than 2?µm. Only small polydisperse primary particles with sizes such as 0.65?±?0.28?µm achieved a high FPF with (68.94?±?6.22%) or without (53.95?±?4.59%) a spacer. Oropharyngeal models also indicated a narrower aerosol particle size distribution for a pMDI containing monodisperse primary particles compared to a conventional pMDI. It is concluded that, pMDIs formulated with monodisperse primary particles show higher FPFs that may target desired regions of the lungs more effectively than polydisperse pMDIs.     

传统漆艺在现代家具中的传承与应用

本文主要从设计与技术两个方面探讨了中国传统漆器工艺与现代实用性家具的结合.通过对现代漆艺家具设计案例的探索分析和对漆艺家具表面绘画装饰上应用的UV喷绘生产工艺研究,旨在将传统漆艺文化在家具现代化大工业生产中传承和发扬,进一步促进创造中国传统文化的设计风格.     

Semiconductor water-based inks: Miniaturized NiO pseudocapacitor electrodes by inkjet printing

The formulation, development and optimization of water-based inks of platelet-like nanoparticles are the main objective of this work. As-synthesized Ni(OH)₂ nanoparticles were dispersed and stabilized in aqueous suspension by PEI addition. The combination of DEG (cosolvent) with H₂O shows the ideal values of surface tension and viscosity for piezoelectric inkjet printing, which exhibits a homogeneous jetting flow of the nanoplatelets suspension. The printed nanostructure was sintered at low temperature (325 °C) and the electrochemical overview of NiO electrode behavior was described. These printable pseudocapacitors tested by a three-electrode cell have showed a competitive specific capacitance, leading 92% and 78% of capacitance retention for 2000 cycles at scan rates of 1 and 2 A/g respectively, and a coulombic efficiency of 100%. The initial performance of this printed NiO pseudocapacitor can be compared with others prepared by conventional methods. This new finding is expected to be particularly useful for the designing of micro-pseudocapacitors.