Flexible Organic Materials Research Articles

Effect of different materials on the performance of flexible organic solar cells

In recent years, in order to solve the shortage of energy resources, organic solar cells have developed rapidly, and the photoelectric conversion efficiency has exceeded 16%. The development of organic solar cells is of great significance to the development of portable devices and the large-scale use of solar power generation in the future. The research of new materials is the key factor in the development of flexible organic solar cells. To develop large-area flexible organic solar cells, it is necessary to develop materials with better comprehensive performance. Now, new progress has been made in new flexible organic materials, which further improves the efficiency of flexible organic solar cells. This review mainly focuses on the analysis of the impact of representative flexible organic solar cell materials on the various of performances of photovoltaic cells in recent years and the prospects for the development of high-efficiency organic solar cells and the main research directions in this field in the future.

26.1: Invited Paper: Organic TFTs for Biaxially formed Active Surfaces

The most common transistor technologies for making active matrix displays and sensors use hard ceramic materials for the semiconducting active layer [1]. To enable flexible displays and electronics, FlexEnable has pioneered an alternative manufacturing approach which uses soft, flexible organic materials as the active layers [2–4]. Organic thin film transistor (OTFT) backplanes using FlexiOMTM materials can be fabricated in standard flat panel display factories which are repurposed for the novel material set. A primary benefit for using OTFT is the inherent durability that comes from removing the brittle ceramic layers. This feature can be further exploited by proactively stretching the devices to conform to more attractive form factor products. This paper will discuss the electrical performance of a state-of-the-art OTFT device and impact of a thermoforming process on switching characteristics.

Halogen-doped phosphorescent carbon dots for grayscale patterning

Flexible organic materials that exhibit dynamic ultralong room temperature phosphorescence (DURTP) via photoactivation have attracted increasing research interest for their fascinating functions of reversibly writing-reading-erasing graphic information in the form of a long afterglow. However, due to the existence of a nonnegligible activation threshold for the initial exposure dose, the display mode of these materials has thus far been limited to binary patterns. By resorting to halogen element doping of carbon dots (CDs) to enhance intersystem crossing and reduce the activation threshold, we were able to produce, for the first time, a transparent, flexible, and fully programmable DURTP composite film with a reliable grayscale display capacity. Examples of promising applications in UV photography and highly confidential steganography were constructed, partially demonstrating the broad future applications of this material as a programmable platform with a high optical information density.

Polyimide-Doped Indium-Gallium-Zinc Oxide-Based Transparent and Flexible Phototransistor for Visible Light Detection.

We report a transparent and flexible polyimide (PI)-doped single-layer (PSL) phototransistor for the detection of visible light. The PSL was deposited on a SiO2 gate insulator by a co-sputtering process using amorphous indium-gallium-zinc oxide (IGZO) and PI targets simultaneously. The PSL acted as both a channel layer and a visible-light absorption layer. PI is one of the few flexible organic materials that can be fabricated into sputtering targets. Compared with the IGZO phototransistor without PI doping, the PSL phototransistor exhibited improved optoelectronic characteristics under illumination with 635 nm red light of 1 mW/mm2 intensity; the obtained photoresponsivity ranged from 15.00 to 575.00 A/W, the photosensitivity from 1.38 × 101 to 9.86 × 106, and the specific detectivity from 1.35 × 107 to 5.83 × 1011 Jones. These improvements are attributed to subgap states induced by the PI doping, which formed decomposed organic molecules, oxygen vacancies, and metal hydroxides. Furthermore, a flexible PSL phototransistor was fabricated and showed stable optoelectronic characteristics even after 10,000 bending tests.

Thermoelasticity of Flexible Organic Crystals from Quasi-harmonic Lattice Dynamics: The Case of Copper(II) Acetylacetonate.

A computationally affordable approach, based on quasi-harmonic lattice dynamics, is presented for the quantum-mechanical calculation of thermoelastic moduli of flexible, stimuli-responsive, organic crystals. The methodology relies on the simultaneous description of structural changes induced by thermal expansion and strain. The complete thermoelastic response of the mechanically flexible metal–organic copper(II) acetylacetonate crystal is determined and discussed in the temperature range 0–300 K. The elastic moduli do not just shrink with temperature but they do so anisotropically. The present results clearly indicate the need for an explicit account of thermal effects in the simulation of mechanical properties of elastically flexible organic materials. Indeed, predictions from standard static calculations on this flexible metal–organic crystal are off by up to 100%.

A novel maleic acid/graphite composite anode for lithium ion batteries with high energy and power density

Herein, a maleic acid/graphite composite is prepared as the anode of lithium ion batteries. Compared to the traditional graphite electrode, the maleic acid/graphite composite electrodes exhibit much improved electrochemical performances in terms of reversible capacity, rate capability and cycling stability. At a current density of 40 mA g−1, a reversible capacity of 1067.3 mAh g−1 is obtained. Even at an extremely high current density of 8 A g−1, a capacity of 889.0 mAh g−1 is retained. The composite electrode is still able to deliver 989.1 mAh g−1 capacity after 1000 cycles at 400 mA g−1 current density, manifesting excellent cycling stability. Mechanisms for the high electrochemical performances of the maleic acid/graphite composite anode are discussed. Reversible lithiation/de-lithiation of the maleic acid nanoballs contributes high capacity to the composite electrode. The mitigated volume expansion of the graphite by the flexible organic material explains the excellent cycling stability of the composite electrode.

Elastic and Bendable Caffeine Cocrystals: Implications for the Design of Flexible Organic Materials

Crystalline spring: Single crystals formed from caffeine, 4-chloro-3-nitrobenzoic acid, and methanol (1:1:<1) have an interlocked structure with weak interactions in the three perpendicular directions, as well as solvent channels, and display reversible elastic bending. Excellent conservation of long-range order even after many bending cycles is observed, thus demonstrating the opportunities for flexible organic materials.

Elastic and Bendable Caffeine Cocrystals: Implications for the Design of Flexible Organic Materials

Federnde Kristalle: Cokristalle aus Koffein, 4-Chlor-3-nitrobenzoesäure und Methanol (1:1:<1) weisen eine verzahnte Struktur mit schwachen Wechselwirkungen in den drei Raumrichtungen auf und lassen sich elastisch und reversibel biegen. Die langreichweitige Ordnung im Kristall bleibt auch nach vielen Biegezyklen erhalten, was Anwendungen als flexibles organisches Material in Aussicht stellt.

Editorial “Strategies for the Improvement of the Metal/Organic Semiconductor Electrical Contact” (Ref: HT-OA-TOAPJ-0001)

Being sure this represents a central point related to the development of organic electronics, with the special issue of The Open Applied Physics Journal “Strategies for the Improvement of the Metal/Organic Semiconductor Electrical Contact”, we organized three contributions offered by groups among the most authoritative in the field, giving a comprehensive landscape of the problematic and approaches adopted for solving this major issue. The first contribution of the special issue has been worked out by the group of Prof. Gilles Horowitz in Paris. It deals with the specific objective of the tuning of the contact resistance of metal/organic junctions. The second contribution comes from the group of Prof. Martin Knupfer in Dresden and focuses on the investigation of the electronic structure of metal/organic interfaces, with a particular emphasis placed on the description of realistic (i.e. contaminated) systems with application in electronics and spintronics. The last contribution presented has been worked out by the group of Prof. Shlomo Magdassi in Jerusalem, giving a comprehensive review of innovative metallization methods having more and more relevance in the context of the fabrication of devices based on soft, flexible organic materials. The ensemble of the contributions allows the reader, even though non-specialized, to approach straight away the state-ofthe-art in the field of organic electronics, to identify the most fruitful investigation techniques adopted up to now for the study of the electrical and electronic properties of organic functional materials, and to know interdisciplinary approaches for the development of a competitive technology.

A flexible capacitive device for pressure and tactile sensing

A new type of capacitive sensor based on flexible organic material is presented. The device fabrication is based on a lamination process of copper-clad laminated composites. The device was evaluated both as pressure and tactile sensor. The proposed fabrication technology presents several advantages concerning the direct integration with the corresponding electronics, the flexibility of the structure, the direct modification of the final geometry and the simplicity of the process.

Room‐Temperature Growth of Silicon Oxide Nanofilms: New Opportunities for Plastic Electronics

A new generation of plastic transistors consisting primarily of light and flexible organic materials requires new fabrication methods which combine low-temperature, solution-phase processing with precise control in the nanometer range over the component dimensions. Ultrathin silicon oxide films, which serve as gate dielectric layers in these transistors, were recently grown at room temperature from polymer precursor films by a novel layer-by-layer deposition/oxidation process.

Environmental Adaptations of Elphidium subarcticum: ABSTRACT

Elphidium subarcticum Cushman, a free, benthic, hyaline foraminifer, has been observed in several localities encrusted with extraneous material and adapted to an attached mode of life. The protozoan appears to secrete an organic sheath upon which foreign material is either agglutinated or precipitated. Several forms were acidized and one that was heavily encrusted and firmly attached on its side to a quartz grain left an internal residue of an organic matrix and a cyst-like sheath of flexible organic material. This sheath is composed of loosely interlocked, silt-sized quartz particles. Scanning-scope photos of the unacidized encrusted form reveals a random arrangement of carbonate particles of various sizes. E. subarcticum may be strengthening its test in response to stresses in the environment. The attachment of the foraminifer on rock fragments is interpreted as an adaption in a high-energy environment. End_of_Article - Last_Page 923------------