Flexible low-voltage organic phototransistors based on air-stable dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT)
TL;DR: In this paper, high-performance, lowvoltage organic thin-film transistors based on dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) are thoroughly characterized with respect to their optical functionality.
About: This article is published in Organic Electronics.The article was published on 2015-05-01. It has received 55 citations till now. The article focuses on the topics: Biasing & Transistor.
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TL;DR: The recent advances of organic photodetectors in terms of both optoelectronic and mechanical properties are outlined and discussed, and their application in wearable electronics including health monitoring sensors, artificial vision, and self-powering integrated devices are highlighted.
Abstract: Next-generation wearable electronics will need to be mechanically flexible and stretchable such that they can be conformally attached onto the human body. Photodetectors that are available in today's market are based on rigid inorganic crystalline materials and they have limited mechanical flexibility. In contrast, photodetectors based on organic polymers and molecules have emerged as promising alternatives due to their inherent mechanical softness, ease of processing, tunable optoelectronic properties, good light sensing performance, and biocompatibility. Here, the recent advances of organic photodetectors in terms of both optoelectronic and mechanical properties are outlined and discussed, and their application in wearable electronics including health monitoring sensors, artificial vision, and self-powering integrated devices are highlighted.
325 citations
TL;DR: The transparent active MEA showed the spatial mapping of electrocorticogram electrical signals from an optogenetic rat with 1-mm spacing and shows lower light artifacts than noise level and would open up the possibility of precise investigation of a neural network system with direct light stimulation.
Abstract: Mechanically flexible active multielectrode arrays (MEA) have been developed for local signal amplification and high spatial resolution. However, their opaqueness limited optical observation and light stimulation during use. Here, we show a transparent, ultraflexible, and active MEA, which consists of transparent organic electrochemical transistors (OECTs) and transparent Au grid wirings. The transparent OECT is made of Au grid electrodes and has shown comparable performance with OECTs with nontransparent electrodes/wirings. The transparent active MEA realizes the spatial mapping of electrocorticogram electrical signals from an optogenetic rat with 1-mm spacing and shows lower light artifacts than noise level. Our active MEA would open up the possibility of precise investigation of a neural network system with direct light stimulation.
178 citations
TL;DR: In this article, a solution-processed phototransistor composed of a heterostructure between a high-mobility organic semiconductor and an organic bulk heterojunction is presented.
Abstract: Solution-processed phototransistors can substantially advance the performance of image sensors. Phototransistors exhibit large photoconductive gain and a sublinear responsivity to irradiance, which enables a logarithmic sensing of irradiance that is akin to the human eye and has a wider dynamic range than photodiode-based image sensors. Here, we present a novel solution-processed phototransistor composed of a heterostructure between a high-mobility organic semiconductor and an organic bulk heterojunction. The device efficiently integrates photogenerated charge during the period of a video frame then quickly discharges it, which significantly increases the signal-to-noise ratio compared with sampling photocurrent during readout. Phototransistor-based image sensors processed without photolithography on plastic substrates integrate charge with external quantum efficiencies above 100% at 100 frames per second. In addition, the sublinear responsivity to irradiance of these devices enables a wide dynamic range of 103 dB at 30 frames per second, which is competitive with state-of-the-art image sensors. A solution-processed organic phototransistor is operated at 100-frame-per-second rates with external quantum efficiencies above 100%. Dynamic range as high as 103 dB was shown for 30-frame-per-second operation.
119 citations
TL;DR: In this article, the authors reported highly sensitive phototransistors with the highly aligned C8-BTBT polycrystalline fi lms as the active layers, which had an edge-on alignment on the substrate and form monoclinic crystal structure.
Abstract: solution methods, making them quite promising in the mass production of optoelectronic devices with low cost. [ 18 ] Organic semiconductors are appealing light detection materials due to their much stronger light absorption than most inorganic counterparts. [ 19,20 ] Nevertheless, the low carrier mobility of organic semiconductors, which is usually in a range of 10 −6 –1.0 cm 2 V −1 s −1 , limits their application for high performance photodetectors. Encouragingly, we recently demonstrated that C8-BTBT polycrystalline fi lms fabricated by an “off-centre spin-coating” method can have an ultrahigh average hole carrier mobility of 25 cm 2 V −1 s −1 . [ 21 ] This high carrier mobility provides a platform for exploring high performance organic photodetectors. In this study, we reported highly sensitive phototransistors with the highly aligned C8-BTBT polycrystalline fi lms as the active layers. The organic transistor we used here has a top-contacted bottom-gated structure ( Figure 1 a). The highly aligned C8-BTBT polycrystalline fi lms were casted from a blended solution of C8-BTBT and polystyrene (PS) using the “offcentre spin-coating” method. [ 21 ] The molecular structures of C8-BTBT and PS are shown in Figure 1 a. The C8-BTBT fi lms had an edge-on alignment on the substrate and form monoclinic crystal structure. The in-plane stacking of the C8-BTBT molecules is illustrated in Figure 1 a. Highly doped silicon wafer with a 300 nm SiO 2 layer was used as the substrate and gate electrode, which also demonstrates the direct integration of the organic phototransistors with silicon chips. The dielectric layer contains the 300 nm thermally grown SiO 2 layer and a 330 nm crosslinked poly(4-vinylphenol) (PVP) layer, [ 22 ] which has a total specifi c capacitance of 6 × 10 −5 F m −2 . We used thick dielectric layer because it can cause smaller leakage current and a larger threshold voltage shift that is needed for sensitive photodetection reported here (see Figure S1 in the Supporting Information). [ 23 ]
66 citations
TL;DR: A dual-gate structure that combines the operation of photodiodes and phototransistors to enable both amplified and linear response without external circuitry is shown, promising for high-performance and scalable photodetector with tunable dynamic range.
Abstract: The conversion of light into electrical signal in a photodetector is a crucial process for a wide range of technological applications. Here we report a new device concept of dual-gate phototransistor that combines the operation of photodiodes and phototransistors to simultaneously enable high-gain and linear photoresponse without requiring external circuitry. In an oppositely biased, dual-gate transistor based on a solution-processed organic heterojunction layer, we find that the presence of both n- and p-type channels enables both photogenerated electrons and holes to efficiently separate and transport in the same semiconducting layer. This operation enables effective control of trap carrier density that leads to linear photoresponse with high photoconductive gain and a significant reduction of electrical noise. As we demonstrate using a large-area, 8 × 8 imaging array of dual-gate phototransistors, this device concept is promising for high-performance and scalable photodetectors with tunable dynamic range.
65 citations
References
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TL;DR: The future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
Abstract: Organic electronics are beginning to make significant inroads into the commercial world, and if the field continues to progress at its current, rapid pace, electronics based on organic thin-film materials will soon become a mainstay of our technological existence. Already products based on active thin-film organic devices are in the market place, most notably the displays of several mobile electronic appliances. Yet the future holds even greater promise for this technology, with an entirely new generation of ultralow-cost, lightweight and even flexible electronic devices in the offing, which will perform functions traditionally accomplished using much more expensive components based on conventional semiconductor materials such as silicon.
4,967 citations
"Flexible low-voltage organic photot..." refers background in this paper
...Organic thin-film transistors (OTFTs) and circuits pose a promising way of manufacturing electronic systems with new properties, as they can be fabricated on flexible, largearea substrates [1,2]....
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TL;DR: Flexible active-matrix monochrome electrophoretic displays based on solution-processed organic transistors on 25-μm-thick polyimide substrates based on 1,888 transistors are demonstrated, which are the largest organic integrated circuits reported to date.
Abstract: At present, flexible displays are an important focus of research1,2,3 Further development of large, flexible displays requires a cost-effective manufacturing process for the active-matrix backplane, which contains one transistor per pixel One way to further reduce costs is to integrate (part of) the display drive circuitry, such as row shift registers, directly on the display substrate Here, we demonstrate flexible active-matrix monochrome electrophoretic displays based on solution-processed organic transistors on 25-μm-thick polyimide substrates The displays can be bent to a radius of 1 cm without significant loss in performance Using the same process flow we prepared row shift registers With 1,888 transistors, these are the largest organic integrated circuits reported to date More importantly, the operating frequency of 5 kHz is sufficiently high to allow integration with the display operating at video speed This work therefore represents a major step towards 'system-on-plastic'
1,577 citations
TL;DR: This work has successfully developed conformable, flexible, large-area networks of thermal and pressure sensors based on an organic semiconductor, and, by means of laminated sensor networks, the distributions of pressure and temperature are simultaneously obtained.
Abstract: Skin-like sensitivity, or the capability to recognize tactile information, will be an essential feature of future generations of robots, enabling them to operate in unstructured environments. Recently developed large-area pressure sensors made with organic transistors have been proposed for electronic artificial skin (E-skin) applications. These sensors are bendable down to a 2-mm radius, a size that is sufficiently small for the fabrication of human-sized robot fingers. Natural human skin, however, is far more complex than the transistor-based imitations demonstrated so far. It performs other functions, including thermal sensing. Furthermore, without conformability, the application of E-skin on three-dimensional surfaces is impossible. In this work, we have successfully developed conformable, flexible, large-area networks of thermal and pressure sensors based on an organic semiconductor. A plastic film with organic transistor-based electronic circuits is processed to form a net-shaped structure, which allows the E-skin films to be extended by 25%. The net-shaped pressure sensor matrix was attached to the surface of an egg, and pressure images were successfully obtained in this configuration. Then, a similar network of thermal sensors was developed with organic semiconductors. Next, the possible implementation of both pressure and thermal sensors on the surfaces is presented, and, by means of laminated sensor networks, the distributions of pressure and temperature are simultaneously obtained.
1,364 citations
TL;DR: In this article, a facile three-step synthetic procedure for highly π-extended heteroarenes, dinaphtho[2,3-b:2‘,3‘-f]thieno[3,2-b]thiophene (DNTT), and DNSS, was established, and the highest field effect mobility of DNTT-and DNSS-based OFETs is 2.9 and 1.9 cm2 V-1 s-1, respectively.
Abstract: A facile three-step synthetic procedure for highly π-extended heteroarenes, dinaphtho[2,3-b:2‘,3‘-f]thieno[3,2-b]thiophene (DNTT) and dinaphtho[2,3-b:2‘,3‘-f]selenopheno[3,2-b]selenophene (DNSS), was established. Solution UV−vis spectra and electrochemistry indicated that they have relatively low-lying HOMO levels and large HOMO−LUMO energy gaps. OFET devices fabricated with evaporated thin-films of DNTT and DNSS showed excellent FET characteristics in air, and the highest field-effect mobility of DNTT- and DNSS-based OFETs is 2.9 and 1.9 cm2 V-1 s-1, respectively.
781 citations
"Flexible low-voltage organic photot..." refers methods in this paper
...Contents lists available at ScienceDirect Organic Electronics journal homepage: www.elsevier .com/locate /orgel Flexible low-voltage organic phototransistors based on air-stable dinaphtho[2,3-b:20,30-f]thieno[3,2-b]thiophene (DNTT) http://dx.doi.org/10.1016/j.orgel.2015.02.007 1566-1199/ 2015 Elsevier B.V....
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...The effect of illumination on high-performance, lowvoltage, DNTT-based OTFTs was thoroughly investigated....
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...With proper biasing, the absorption of UV/blue light in the p-channel organic semiconductor DNTT leads to a significant increase in the density of free electrons, which can be trapped in the AlOx of the gate dielectric or in the semiconductor, at grain boundaries or structural defects reaching the interface of the SAM....
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...The optical absorption properties of the organic semiconductor DNTT are determined by a transmission measurement....
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...In this work, high-performance, low-voltage organic thin-film transistors based on dinaphtho[2,3-b:20,30-f]thieno[3,2-b]thiophene (DNTT) are thoroughly characterized with respect to their optical functionality....
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05 Jul 2005
TL;DR: Progress is reported on in developing materials, processes, and devices for the realization of ultralow-cost printed RFID tags using novel pentacene and oligothiophene precursors for pMOS and ZnO nanoparticles for nMOS.
Abstract: Printed electronics provides a promising potential pathway toward the realization of ultralow-cost RFID tags for item-level tracking of consumer goods. Here, we report on our progress in developing materials, processes, and devices for the realization of ultralow-cost printed RFID tags. Using printed nanoparticle patterns that are subsequently sintered at plastic-compatible temperatures, low-resistance interconnects and passive components have been realized. Simultaneously, printed transistors with mobilities >10/sup -1/ cm/sup 2//V-s have been realized using novel pentacene and oligothiophene precursors for pMOS and ZnO nanoparticles for nMOS. AC performance of these devices is adequate for 135-kHz RFID, though significant work remains to be done to achieve 13.56-MHz operation.
501 citations