Pentacene-Based Photodetector in Visible Region With Vertical Field-Effect Transistor Configuration
TL;DR: In this paper, the VFET-based photo-detector with ITO/Pentacene(80 nm)/Al(15 nm) configuration was investigated in full visible region.
Abstract: Electrical and detection performances of pentacene-based photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based photo-detector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. $-8\times 10^{-7}$ A, the threshold voltage ( $V_{\rm th}$ ) was −0.61 V for the VFET-based device at $V_{\mathrm {DS}} = -2$ V, but $V_{\mathrm {th}} = -7.1$ V for the planar one at $V_{\mathrm {DS}} = -12$ V. The performance of photodetectors depends on incident monochromatic light, and the VFET-based photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were $\sim 11.75$ and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.
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TL;DR: Organic photodiodes (OPDs) are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity.
Abstract: Major growth in the image sensor market is largely as a result of the expansion of digital imaging into cameras, whether stand-alone or integrated within smart cellular phones or automotive vehicles. Applications in biomedicine, education, environmental monitoring, optical communications, pharmaceutics and machine vision are also driving the development of imaging technologies. Organic photodiodes (OPDs) are now being investigated for existing imaging technologies, as their properties make them interesting candidates for these applications. OPDs offer cheaper processing methods, devices that are light, flexible and compatible with large (or small) areas, and the ability to tune the photophysical and optoelectronic properties − both at a material and device level. Although the concept of OPDs has been around for some time, it is only relatively recently that significant progress has been made, with their performance now reaching the point that they are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity. This review covers the progress made in the OPD field, describing their development as well as the challenges and opportunities.
499 citations
TL;DR: This review focuses on the advancements of using organic field-effect transistors (OFETs) in flexible electronic applications in the past 10 years, and introduces organic semiconductors (OSCs), followed by their applications in various device configurations and their mechanisms.
Abstract: Flexible electronic devices have attracted a great deal of attention in recent years due to their flexibility, reduced complexity and lightweight. Such devices can conformably attach themselves to any bendable surface and can possess diverse transduction mechanisms. Consequently, with continued emphasis on innovation and development, major technological breakthroughs have been achieved in this area. This review focuses on the advancements of using organic field-effect transistors (OFETs) in flexible electronic applications in the past 10 years. In addition, to the above mentioned features, OFETs have multiple advantages such as low-cost, readout integration, large-area coverage, and power efficiency, which yield synergy. To begin with, we have introduced organic semiconductors (OSCs), followed by their applications in various device configurations and their mechanisms. Later, the use of OFETs in flexible sensor applications is detailed with multiple examples. Special attention is paid to discussing the effects induced on physical parameters of OFETs with respect to variations in external stimuli. The final section provides an outlook on the mechanical aspects of OSCs, activation and revival processes of sensory layers, small area analysis, and pattern recognition techniques for electronic devices.
195 citations
TL;DR: Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies, and in this review, these different approaches are compared and recent progress is highlighted.
Abstract: Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted.
69 citations
TL;DR: These findings strongly support and promote the use of the single-crystal Pt complex (1o) in next-generation organic optoelectronic devices.
Abstract: Organic semiconductors demonstrate several advantages over conventional inorganic materials for novel electronic and optoelectronic applications, including molecularly tunable properties, flexibility, low-cost, and facile device integration. However, before organic semiconductors can be used for the next-generation devices, such as ultrafast photodetectors (PDs), it is necessary to develop new materials that feature both high mobility and ambient stability. Toward this goal, a highly stable PD based on the organic single crystal [PtBr2 (5,5'-bis(CF3 CH2 OCH2 )-2,2'-bpy)] (or "Pt complex (1o)") is demonstrated as the active semiconductor channel-a material that features a lamellar molecular structure and high-quality, intraligand charge transfer. Benefitting from its unique crystal structure, the Pt-complex (1o) device exhibits a field-effect mobility of ≈0.45 cm2 V-1 s-1 without loss of significant performance under ambient conditions even after 40 days without encapsulation, as well as immersion in distilled water for a period of 24 h. Furthermore, the device features a maximum photoresponsivity of 1 × 103 A W-1 , a detectivity of 1.1 × 1012 cm Hz1/2 W-1 , and a record fast response/recovery time of 80/90 µs, which has never been previously achieved in other organic PDs. These findings strongly support and promote the use of the single-crystal Pt complex (1o) in next-generation organic optoelectronic devices.
54 citations
TL;DR: In this paper, a solution-processed near-infrared (NIR) photodetector based on PbSe colloidal quantum dots (CQDs) with a field effect transistor (FET) configuration was presented.
Abstract: A solution-processed near-infrared (NIR) photodetector based on PbSe colloidal quantum dots (CQDs) with a field-effect transistor (FET) configuration was presented. By blending PbSe CQDs into poly(3-hexylthiophene-2, 5-diyl) (P3HT) as active layer, the photosensitive spectrum of P3HT:PbSe nanocomposites extends into the NIR region. The responsivity and the specific detectivity of FET-based photodetector Au(gate)/PMMA (930nm)/P3HT:PbSe(55nm)/Au(source, drain) reached 500 A/W and $5.02 \times 10^{12}$ Jones, respectively, at $V_{\rm DS}=-40$ V and $V_{\rm G}=-40$ V with 40 mW/cm $^{2}$ of 980-nm laser illumination. It gets more stable due to its reverse fabrication using the dielectric layer to cover the active layer from environment air.
38 citations
Cites background from "Pentacene-Based Photodetector in Vi..."
...For a phototransistor, responsivity (R) and photosensitivity (P) are two key parameters characterizing its performance [30], [31]....
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References
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TL;DR: An approach--termed fluid-enhanced crystal engineering (FLUENCE)--that allows for a high degree of morphological control of solution-printed thin films and may find use in the fabrication of high-performance, large-area printed electronics.
Abstract: Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach—termed fluid-enhanced crystal engineering (FLUENCE)—that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V−1 s−1 and 11 cm2 V−1 s−1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics. Solution printing of organic semiconductors could in principle be scaled to industrial needs, yet attaining aligned single-crystals directly with this method has been challenging. By using a micropillar-patterned printing blade designed to enhance the control of crystal nucleation and growth, thin films of macroscopic, highly aligned single crystals of organic semiconductors can now be fabricated.
876 citations
"Pentacene-Based Photodetector in Vi..." refers methods in this paper
...To find more extensive applications in the optoelectronic integrated circuit, many efforts have been developed to improve the performance of OFETs [16]–[20], such as varying the device structure, controlling the molecular orientation, modifying function layers and electrode interfaces, preparing new organic materials and using new preparation technology....
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TL;DR: An organic field effect transistor featuring the chiral molecule helicene acts as a photodetector that is able to distinguish between left and right-handed circularly polarized light.
Abstract: An organic field effect transistor featuring the chiral molecule helicene acts as a photodetector that is able to distinguish between left- and right-handed circularly polarized light.
642 citations
"Pentacene-Based Photodetector in Vi..." refers background in this paper
...Similar to inorganic semiconductors, OSCs can also respond to incident light quickly [5]–[7], which encourages researchers to combine the photoconductive effect of OSCs with the field effect of OFETs to fabricate OFET-based photodetectors [8]–[12] with high detectivity...
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TL;DR: The concept of using a p-channel/emitter/n-channel trilayer semiconducting heterostructure in OLETs is introduced, providing a new approach to markedly improve OLET performance and address general fundamental optoelectronic and photonic issues.
Abstract: The potential of organic semiconductor-based devices for light generation is demonstrated by the commercialization of display technologies based on organic light-emitting diodes (OLEDs). Nonetheless, exciton quenching and photon loss processes still limit OLED efficiency and brightness. Organic light-emitting transistors (OLETs) are alternative light sources combining, in the same architecture, the switching mechanism of a thin-film transistor and an electroluminescent device. Thus, OLETs could open a new era in organic optoelectronics and serve as testbeds to address general fundamental optoelectronic and photonic issues. Here, we introduce the concept of using a p-channel/emitter/n-channel trilayer semiconducting heterostructure in OLETs, providing a new approach to markedly improve OLET performance and address these open questions. In this architecture, exciton-charge annihilation and electrode photon losses are prevented. Our devices are >100 times more efficient than the equivalent OLED, >2x more efficient than the optimized OLED with the same emitting layer and >10 times more efficient than any other reported OLETs.
538 citations
TL;DR: This work demonstrates an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors, comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.
Abstract: Intrinsic nonuniformity in the polycrystalline-silicon backplane transistors of active matrix organic light-emitting diode displays severely limits display size. Organic semiconductors might provide an alternative, but their mobility remains too low to be useful in the conventional thin-film transistor design. Here we demonstrate an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors. The high level of performance is enabled by a single-wall carbon nanotube network source electrode that permits integration of the drive transistor and the light emitter into an efficient single stacked device. The performance demonstrated is comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.
436 citations
TL;DR: In this paper, the effect of light incident on a polymer-based field effect transistor was investigated and the utility of light as an additional controlling parameter of the transistor state was demonstrated.
Abstract: We report the effect of light incident on a polymer-based field-effect transistor and demonstrate the utility of light as an additional controlling parameter of the transistor state. The transistor exhibits large photosensitivity indicated by the sizable changes in the drain–source current at low levels of light. The response here is considerably higher than that from existing organic/polymeric planar, two-terminal photodetectors due to an additional process contributing to the enhancement. The light-responsive polymer transistor opens up a device-architecture concept for polymer-based electronics.
211 citations
"Pentacene-Based Photodetector in Vi..." refers background in this paper
...Similar to inorganic semiconductors, OSCs can also respond to incident light quickly [5]–[7], which encourages researchers to combine the photoconductive effect of OSCs with the field effect of OFETs to fabricate OFET-based photodetectors [8]–[12] with high detectivity...
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