Enhancing Reliability of LEDs and other Display Devices

The rise of paper electronics has been accelerated due to the public push for sustainability. Electronic waste can potentially be avoided if certain materials in electronic components can be substituted for greener alternatives such as paper. Within this report, it is demonstrated that conductive polymers poly(3,4‐ethylenedoxythiophene) (PEDOT), polypyrrole, and polythiophene, can be synthesized by screen printing combined with vapor phase polymerization on paper substrates and further incorporated into functional electronic components. High patterning resolution (100 µm) is achieved for all conductive polymers, with PEDOT showing impressive sheet resistance values. PEDOT is incorporated as conductive circuitry and as the active material in all‐printed electrochromic displays. The conductive polymer circuits allow for functional light emitting diodes, while the electrochromic displays are comparable to commercial displays utilizing PEDOT on plastic substrates.

ConspectusRedox active organic and polymeric materials have witnessed the rapid development and commercialization of lithium-ion batteries (LIBs) over the last century and the increasing interest in developing various alternatives to LIBs in the past 30 years. As a kind of potential alternative, organic and polymeric materials have the advantages of flexibility, tunable performance through molecular design, potentially high specific capacity, vast natural resources, and recyclability. However, until now, only a handful inorganic materials have been adopted as electrodes in commercialized LIBs. Although the development of carbonyl-based materials revived organic batteries and stimulated plentiful organic materials for batteries in the past 10 years due to their high theoretical capacities and long-term cycleabilities compared with their pioneers (e.g., conducting polymers), organic batteries are still facing many challenges. For example, it is still essential to enhance the theoretical and experimental capacities of organic materials. Moreover, typically, organic materials suffer relatively low conductivity, which limits their rate capability. In addition, many organic materials, especially small molecules, show poor cycling stability because of their dissolution in organic electrolytes. Other requirements, such as high voltage output and low cost, are also crucial for organic batteries. Therefore, insights into fundamentals (e.g., intramolecular and intermolecular interactions) for a deep understanding of organic batteries and constructive strategies ranging from material design to manipulation of other components (e.g., conductive additives, binders, electrolytes, and separators through controlling the intramolecular and intermolecular interactions and manipulating the ionic transport) are of great significance to boost the performance of organic batteries.In this Account, we give an overview of our efforts to develop high performance organic batteries with various strategies from the aspects of molecular design and the manipulation of other components. Inspired by the experience in organic electronics, we proposed that the extension of the π-conjugated system is helpful for stabilizing the +1/-1 charge/discharge states, improving the charge transport, and facilitating the layered packing (good for ionic diffusion) and hence would benefit the rate capability and cyclability. The π-d conjugation can effectively improve the electrical conductivity and provide stable and fast ionic storage, which enriches the materials for high-performance batteries and further deepens the understanding of conjugated coordination polymers (CCPs). Different from inorganic materials, organic materials are composed of molecules (either small molecules, macromolecules, or polymeric molecules) with weak intermolecular interactions. Therefore, the manipulation of active molecules or additives (conductive additives, binders, and other special additives) through control of intermolecular interactions is crucial for enhancing the electrochemical performance of organic batteries. Regarding the possible dissolution of active materials, the modification of separators through addition of selectively permeable membranes as ionic sieves is the most efficient and universal strategy to mitigate the shuttling of dissolved molecules but allow smaller sized cations to pass and hence is able to enhance the cyclability. On the basis of these findings, the challenges and several future trends for organic batteries are discussed. This Account provides a summary of our recent progress, understanding of the fundamentals for high performance organic batteries, insight into the intramolecular and intermolecular interactions, and prospects for future development of organic materials for next-generation rechargeable batteries.

This paper addresses the complex problem of orchestrating flexible and dynamic federation of Future Internet Networks (FINs) where multiple autonomic management systems (AMSs) are expected to collaborate so as to maximize gain or achieve higher-level goals. We envision an orchestration plane coordinating the interaction among the AMSs. When any form of federation is required (e.g. merging of virtual networks), the relevant AMSs negotiate among themselves under the directives of the orchestration plane to reach an agreement that is acceptable to all involved parties. To this end, we define a negotiation framework with alternating offers. We devise a negotiation strategy for the AMSs which takes into account their own patience and attitude to risk for the case where they are completely ignorant of the character of their counterparts. We illustrate by simulation how the strategy converges to agreement and show the effects of various types of AMSs on the final outcome. Finally, we present a case study to demonstrate the operation of the proposed framework.

A new development in the area of vapor phase deposited conformal and protective coatings, which offers solutions to many existing packaging and reliability challenges of power electronic component industry. A newly developed product, Parylene HT (W.R. Dolbier Jr. et al., 1998), possesses unique properties compared to all existing Parylenes and other vapor phase coatings. Experimental results and trial runs demonstrate the ability of Parylene HT coating to meet the growing requirements of higher dielectric capabilities, higher temperature integrity and mechanical processing etc. of dynamic power electronic industry. Parylene HT can easily be applied on stators, cores, torrids, capacitors, inductors, power supply electronics, batteries and ceramics for high performance and reliability.

Significant performance and reliability challenges exist for high temperature electronics used in many applications, including those used in down-hole, under-bonnet, well-logging and aero-engine applications. Under high temp operating environments, the life expectancy of electronic components and systems reduces exponentially if they are not designed, packaged and protected appropriately to tolerate or negate the impact of high temperatures. This presentation highlights specific materials and conformal coating issues that play a significant role in addressing above challenges and presents results of thermal aging effects on Parylene HT at 250°C and up to 450°C. In addition, it provides an in-depth analysis of its performances at high temperatures and offers solutions to some existing issues through incorporating Parylene HT in the design and final protection of high temperature electronics.

High speed Analog-to-Digital Converters (ADCs) are key components for enhancing high-speed communication systems, such as broadband satellites at millimeter wave frequencies [1] and extremely high-throughput wireless systems [2]. Tens of gigahertz ADCs are required to cope with the increasing need of real-time digital signal processing of broad bandwidth analog RF signal in direct digital receivers. Electronic ADCs have inherent limitations for reaching high bandwidth with an appropriate resolution [3] due to the high timing jitters of electronics clocks, state of art values over 100 fs for [4]. We are studying an All-Optical Analog-to-Digital Converter (AOADC) based on an Electro-Optic (EO) polymer deflector [5] for achieving higher than 20 GHz of bandwidth with a 6 bits of resolution, taking advantage of much lower timing jitters of modes-locked lasers on one hand and very good materials qualities of EO polymers on the other hand (excellent velocity matching between the microwave signals and optical waves in polymeric materials and EO coefficient up to 350 pm/V versus 31 pm/V of the popular inorganic crystal LiNbO 3 ). The EO deflector converts magnitude variation of the analog RF voltage, applied on its Coupled Mirco-Strip (CMS) driving electrodes, into variations of deflection angle of an optical leaky beam out of the optical deflector using the linear EO effect (Pockels effect). This variation of deflection angle as result of the applied RF signal is then quantized using optical windows followed by an array of high-speed photodetectors. This paper reports design optimization of an EO deflector based on polymer materials. On the one hand, the leaky optical waveguide is optimized for achieving up to 6.3 bits of resolution, on the other hand, a transition from coplanar waveguide pads (CPW) to the CMS line is designed for RF characterization of optical deflectors by means of Ground-Signal-Ground (GSG) probes. Experimental validation of 2 cm long of via-free CPW-CMS transition built on a 40 µm thick Benzo Cyclo Butene (BCB) polymer shows a bandwidth higher than 25 GHz. This transition is very helpful for packaging and connectorization of photonic-microwave devices.

This article discusses the estimated failure rate of electronic components when these are exposed to harsh environment involving vibration, dust, humidity, high temperatures, and others. So, it presents a compilation of the resulting physical-chemical effects upon stressed electronic components, and how such effects can reduce the component life. Also presented here is a compilation of the results of an ample and thorough research of different standards of reliability prediction, making it a critical and comparative analysis between the different techniques, methodologies and applications of each standard studied. Furthermore, for the reader to have a broader understanding of the methodology used in standards, an example is presented of a typical SV-PWM converter used in motor drive systems under different environmental aspects, in order to compare the methods under study.

A multi-disciplinary study of vibration based reliability of lead-free electronic interconnects

Kacapiring (Gardenia jasminoides) is an ornamental plant that has many uses, as a cut flowers, food ingredients, textile materials, cosmetic raw materials, and containing therapeutic compounds. The high demand for gardenia needs to be balanced with the results of its cultivation. Conventional propagation of gardenias has disadvantages such as a long life cycle, genotypes can differ from the parent, and can carry disease from the parent. Therefore, more efficient gardenia propagation techniques are needed, one of which is by making synthetic seeds. Synthetic seeds can be produced by encapsulating somatic embryos. Somatic embryos are collections of embryonic cells formed from soma cells that have the ability to regenerate into a complete new plant. Hormones are organic materials that occur naturally in plants or are synthetic. Hormones have an effect on plant differentiation and growth. Somatic embryogenesis can be carried out using auxin and cytokinin hormones, because auxins can induce embryogenic callus and cytokinins can initiate the embryogenic process in callus. Synthetic seeds are single somatic embryos covered by a matrix, so that they can be stored for a certain duration of time and can grow into a complete plant in both in vitro and ex vitro conditions. This literature review is to provide an overview based on existing references on the effects of various types of hormones for the induction of gardenia somatic embryos, synthetic seed production methods, and synthetic seed storage temperatures.

Electrochromic organic and polymeric materials for display applications

This study assessed the impact of commercial packaging on the stability and identity of Copioba cassava flour. Flour was packaged in low-density polyethylene (LDPE), polypropylene (PP), and metallized biaxially oriented polypropylene (BOPP) films. Quality changes over time were evaluated via moisture content, water activity (aw), pH, titratable acidity, texture/hardness, color, fatty acid composition, and specific microorganisms. Moisture content and aw increased in the LDPE-packaged flour and the control group. At the end of the storage period, levels of fatty acids had decreased by 55.81–68.28%, with only minor changes in aw. There was a rise in yeast and mold levels up to 4 log CFU/g in flour packaged in LDPE films. In contrast, the levels of Bacillus cereus in flour packaged in PP and BOPP ranged from <1 to 2.30 log CFU/g. PP and BOPP films exhibited the most effective performance among the packaging materials evaluated. The results obtained in this study will contribute to the pursuit of a Geographical Indication GI certification by providing information about the best packaging type for preserving the unique characteristics of Copioba cassava flour, as no study has previously reported on the best type of packaging material for Copioba flour.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Novel and Perfectly Aligned Highly Electro−Optic Organic Cocrystal of a Merocyanine Dye and 2,4-DihydroxybenzaldehydeFeng Pan, Man Shing Wong, Volker Gramlich, Christian Bosshard, and Peter GünterView Author Information Nonlinear Optics Laboratory Institute of Quantum Electronics ETH-Hönggerberg, CH-8093 Zürich, Switzerland Cite this: J. Am. Chem. Soc. 1996, 118, 26, 6315–6316Publication Date (Web):July 3, 1996Publication History Received2 April 1996Published online3 July 1996Published inissue 1 January 1996https://pubs.acs.org/doi/10.1021/ja961087khttps://doi.org/10.1021/ja961087krapid-communicationACS PublicationsCopyright © 1996 American Chemical SocietyRequest reuse permissionsArticle Views831Altmetric-Citations92LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information SUBJECTS:Crystal structure,Crystals,Noncovalent interactions,Optical properties,Polarizability Get e-Alerts

The photorefractive effect is one of the phenomena that can form hologram images in a material. Currently, 3D displays are expected to be widely used as next generation displays. However, current 3D displays are basically stereograms. Holographic displays that can realize natural 3D images that can be seen by the naked eye are anticipated. The photorefractive effect is a phenomenon wherein a change in the refractive index is induced by a combined mechanism of photovoltaic and electro-optic effects. A transparent material that exhibits both photovoltaic and electro-optic effects can potentially be used as a photorefractive material. The interference of two laser beams in a photorefractive material establishes a refractive index grating (Figure 1). When two laser beams interfere in an organic photorefractive material, charge generation occurs at the bright positions of the interference fringes. The generated charges diffuse or drift within the material. Since the mobilities of positive and negative charges are different in most organic materials, a charge separated state is formed. The charge with higher mobility diffuses over a longer distance than the charge with lower mobility, so that while the low mobility charge stays in the bright areas, the high mobility charge moves to the dark areas. The bright and dark positions of the interference fringes are thus charged with opposite polarities, and an internal electric field (space charge field) is generated in the area between the bright and dark positions. The refractive index of this area between the bright and dark positions is changed through the electro-optic effect. Thus, a refractive index grating (or hologram) is formed. One material class that exhibits high photorefractivity is glassy photoconductive polymers doped with high concentrations of D-π-A chromophores (in which donor and acceptor groups are attached to a π-conjugate system). In order to obtain photorefractivity in polymer materials, a high electric field of 10–50 V/μm is usually applied to a polymer film. This electric field is necessary to increase the charge generation efficiency. The photorefractive effect has been reported in surface-stabilized ferroelectric liquid crystals (SS-FLCs) doped with a photoconductive compound. Liquid crystals are classified into several groups. The most well known are nematic liquid crystals and smectic liquid crystals (Figure 2). Nematic liquid crystals are used in LC displays. On the other hand, smectic liquid crystals are very viscous and hence are not utilized in any practical applications. Ferroelectric liquid crystals (FLCs) belong to the class of smectic liquid crystals that have a layered structure. The molecular structure of a typical FLC contains a chiral unit, a carbonyl group, a central core, which is a rigid rod-like structure such as biphenyl, phenylpyrimidine, phenylbenzoate, and a flexible alkyl chain (Figure 3).

Chapter 10 - Crystal-Induced Nanoarchitectonics of Organic Polymer Materials

Polymeric materials are extensively used in the production of microfluidic devices, biomedical equipment, automotive parts, and electronic components. Given the limitations of certain manufacturing methods and the complexity of these products, joining polymeric materials becomes essential. Laser welding presents a promising and innovative approach for this task, offering high productivity, the ability to weld intricate shapes, and access to small or hard-to-reach areas. This review explores recent advancements in laser welding technologies, including butt and transmission welding, and the laser systems involved. It also addresses various welding processes such as similar and dissimilar welding, micro-welding, and the welding of polymers to metals. The quality of welds is evaluated based on joint strength and seam width, which can be controlled through parameters like laser power, scan speed, number of scans, and beam diameter. Given the nonlinear response of polymers to heat, determining optimal welding parameters is crucial. Thus, modeling the laser welding process through numerical, analytical, statistical, and artificial intelligence methods is vital for process understanding and optimization. This paper offers a comprehensive review of laser types, welding techniques, and modeling strategies for welding polymeric materials.