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Polymer Semiconductors
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Polymers in Energy Conversion and Storage, 2022
Moises Bustamante-Torres, Jocelyne Estrella-Nuñez, Odalys Torres, Sofía Abad-Sojos, Bryan Chiguano-Tapia, Emilio Bucio
During the past few years, polymer semiconductors have presented attractive characteristics. Improved film-forming properties can enhance the properties and applications of polymers. Organic semiconductor materials based on heterocyclic monomers like aniline, pyrrole, and thiophene have been widely used in technological applications in organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), organic thin-film transistors (OTFTs), organic photovoltaics (OPVs), rechargeable batteries, and so on (Bouabdallah et al. 2019; Sun, Guo and Facchetti 2020; Qu, Qi and Huang 2021).
Components and Devices
Published in Katsuyuki Sakuma, Krzysztof Iniewski, Flexible, Wearable, and Stretchable Electronics, 2020
Organic semiconductors can be based on small molecules or conjugated polymers. Vapour phase processing is usually used for small molecule deposition, whereas conjugated polymers can be deposited in vapour or solution phase. The array of available materials is vast, with some common options being pentacene or poly(3-hexylthiophene-2,5-diyl) (P3HT)-based polymers [43]. A full review of organic semiconductor materials is beyond the scope of this chapter; however, the there are several excellent review articles which discuss the subject [44–46]. The major advantage of organic semiconductors is the ease of solution processing, with many semiconducting polymers showing good solubility (although chlorinated solvents may be required). In addition, organic semiconductors have also demonstrated good flexibility [47]. However, there are several limitations, chiefly that organic semiconductors are limited in mobility, with values between 0.001 and 10 cm2/Vs common [43]. Device mobility is heavily dependent upon the film formation, with higher mobility devices typically achieved with crystalline films, at the cost of process sensitivity and device-to-device uniformity [45]. Amorphous films are simpler to process, but demonstrate significantly lower mobility. Also, stability is often an issue with organic semiconductors, especially when exposed to oxygen and water vapour [48]. However, the mobility values may be sufficient for many applications and stability issues can be minimised by material selection and encapsulation.
Plastic Electronics
Published in Muhammad Mustafa Hussain, Nazek El-Atab, Handbook of Flexible and Stretchable Electronics, 2019
From a scientific viewpoint, organic semiconductors are carbon-based molecules with varying sizes that have a special chemistry that makes them a tunable electric conductor (thus satisfying the classical notion of semiconductors). This chemical common ground will be also dealt with hereinafter. Suffice it to say that such a somewhat ‘loose’ definition of a materials class translates into a practically unlimited number of possible molecular structures. As the field steadily advances, the material toolbox has exploded, thanks to the consistent synthetic efforts and new applications that validate and guide these efforts [6–14]. Now it seems safe to believe that the once critical stability and lifetime issues have been largely overcome, and the materials developments are now more devoted to obtaining target-specific properties, such as color purity of light-emitting materials, the structural order that facilitates carrier movement, and sensitivity to the environment for harvesting wasted energies. In brief, the material’s exceptional tunability is another key merit that adds to the flexibility, and it is paving the way to a new generation of multi-functional platforms.
Pseudo-transistors for emerging neuromorphic electronics
Published in Science and Technology of Advanced Materials, 2023
Jingwei Fu, Jie Wang, Xiang He, Jianyu Ming, Le Wang, Yiru Wang, He Shao, Chaoyue Zheng, Linghai Xie, Haifeng Ling
Organic channel materials can be fabricated over a large area. According to chemical and physical properties, organic semiconductors can be divided into two molecules materials (C8-BTBT, pentacene, TIPS-pentacene and DNTT). The crystallinity of small molecule semiconductors is generally better than that of polymers, and higher crystallinity facilitates charge transfer. Compared with n-type organic semiconductors, p-type organic semiconductors have the following advantages: (1) elevated highest occupied molecular orbital (HOMO), which is conducive to forming good ohmic contact with electrodes and lower the hole injection barrier [105]. (2) Stable chemical properties, which can maintain excellent environmental stability and working stability. (3) Higher carrier mobility.
Surface topology, optical spectroscopic and electrical studies on boron subphthalocyanine chloride thin films
Published in Journal of Dispersion Science and Technology, 2022
Organic small molecules have been widely used instead of conventional materials (metals and ceramics) due to their great performance in optoelectronic devices. Their distinguished structural, chemical properties and physical features show respectable optoelectronic properties. Attention in organic optoelectronic devices stems from the capability to deposit organic films on a variety of very low-cost substrates such as glass, metal foils or plastic. Electronic devices based on organic thin films are particularly remarkable as their manufacturing procedures are much less complex compared with inorganic thin film technology, which involves high-vacuum deposition processes and high-temperature. In recent days, optical technologies based on organic semiconductors are extensively used in a wide range of modern applications such as medical, telecommunications, sensors, lasers and solar cells. The search for higher performance and complex functionality and lower cost has been the foremost motivation.[1–3] On the other side, several of the remaining challenges are materially related, e.g., the low mobility of electronic charge carriers in organic semiconductor materials, limited organic light-emitting diode (OLED) lifetime due to unstable blue hosts and emitters, low power conversion efficiencies of organic solar cells.[4]
Synthesis and mesomorphic behaviour of highly ordered liquid crystalline D-A-D-type Carbazole-TPD-Carbazole
Published in Phase Transitions, 2020
Guang Hu, Stuart P. Kitney, William Harrison, Brian Lambert
Organic semiconductors such as Organic Photovoltaics (OPVs) and Organic Light-Emitting Diodes (OLEDs), in place of traditional inorganic silicon-based electronics, have been widely studied in recent years due to a simple device structure, easy fabrication via solution processing, flexibility, light weight, low cost, clean energy exploitation, etc. [1–5]. Extensive research for organic semiconductors focused on identifying novel materials including small molecules and polymer materials [6–10]. However, polymer materials are often difficult to purify, dissolve in common organic solvents and achieve a high yield and batch-to-batch reproducibility [10,11]. Therefore, organic semiconducting materials based on small molecules have attracted increasing attention due to advantages, such as well-defined molecular structures, good solubility, appropriate molecular weight, high purity without batch-to-batch variation, etc. [10,11]. Particularly donor–acceptor-donor (D-A-D) molecules have attracted considerable attention due to the ability to fine tune their energy levels and band gap as well as a red shift extension of absorption useful for some opto-electronic applications [12–19]. The ‘Push-Pull’ combination of suitable donor and acceptor moieties in the same molecule allows efficient intra-molecular charge transfer from electron-donor units with high-lying HOMO energy levels to electron-acceptor units possessing low-lying LUMO energy levels. This Push-Pull’ molecular arrangement can promote charge carrier mobility [19–22].