Dark current reduction strategies using edge-on aligned donor polymers for high detectivity and responsivity organic photodetectors

Eom, Seung Hun; Nam, So Youn; Jin, Hee; Lee, Jaemin; Jeon, Seol; Shin, Tae Joo; Jung, In Hwan; Yoon, Sung Cheol; Lee, Changjin

doi:10.1039/c7py00497d

Cited by 34 publications

(26 citation statements)

References 56 publications

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“…The R according to wavelength can be calculated from the external quantum efficiency (EQE) according to the literature and is shown in Figure e,f. At short circuit, we can compare how close the theoretical R value is to the experimental R .…”

Section: Resultsmentioning

confidence: 99%

Improved Performance of Quantum‐Dot Photodetectors Using Cheap and Environmentally Friendly Polyethylene Glycol

Kang

Park

Jeong

et al. 2018

Adv Materials Inter

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there are many important applications, such as imaging and biomedical sensors, [14,15] X-ray detectors, [16] and optical communications. [17] For p-n junction QPDs, important parameters are the interfacial contact properties at the p-n junction because the internal electric field at the interfaces can decrease the trap site and charge recombination for efficient charge transport in QPDs. [18][19][20] Recently, Wei et al. reported promising photodetecting properties by developing hybrid organic/PbS CQD based QPDs. [21] The CQD layer improved the electron transport and prevented charge recombination in the devices. Thus, the bilayer contact between the bulk-heterojunction conjugated organic layer and the CQD active layer significantly decreased the dark current and improved charge collection. However, no studies were done to improve the charge collection and decrease the dark current in QPDs via modifying the interfacial properties among the CQD layer and the electron accepting layers (EALs).In this study, we have focused on the interfacial properties among CQDs and electron-accepting ZnO layers by introducing organic cathode buffer layers (CBLs) to improve the photodetecting properties of QPDs. ZnO is a well-known n-type semiconductor with high electron mobility and transmittance. [22,23] In particular, its low-temperature solution-processability (<150 °C) is appropriate for roll-to-roll printing technology on flexible substrates. [24,25] However, its relatively high work function of ≈4.3 eV requires further electric dipole layers for improving the charge transporting characteristics of the CQD layers. [26] In addition, the rough surface morphology from its crystalline structure worsens the uniform contact among the CQD and ZnO layers. To reduce the surface roughness and work function of the ZnO layer, we introduced polyethylenimine ethoxylated (PEIE) and polyethylene glycol (PEG) as the CBLs. PEIE has multiple hydroxyl side groups, which effectively generate permanent dipole moments at the interface of ZnO, and is successfully utilized in solar cells applications. [27,28] However, in the case of PEG, even though the ethylene glycol functional groups can coordinate with the ZnO layer, it has seldom been used in electronic applications to modify the EALs. [29] PEG is biologically safe, water soluble, and relatively cheap; thus, the utilization of PEG is environmentally and industrially attractive. Colloidal quantum dot (CQD) photodetectors (PDs) are developed. The on/off current ratio is improved by applying organic cathode buffer layers (CBLs), such as polyethylenimine ethoxylated (PEIE) and polyethylene glycol (PEG). The on-current of CQD-PDs (QPDs) is increased by the decreased work function of ZnO/CBLs via forming a permanent dipole moment at the interface of ZnO andCBLs. The off-current is significantly decreased by the improved interfacial morphology via softening the ZnO surfaces. In the photoconductive mode for the fast response time of a signal, PEG-and PEIE-treated QPDs exhibit improved photodetecting pro...

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Section: Resultsmentioning

confidence: 99%

Improved Performance of Quantum‐Dot Photodetectors Using Cheap and Environmentally Friendly Polyethylene Glycol

Kang

Park

Jeong

et al. 2018

Adv Materials Inter

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“…However, an important factor that has a negative impact on the device performance is the chance of corrosion of this polymer material, specifically by photo‐oxidation or photo‐degradation. In a similar way, polymer photodetectors also get a considerable priority in modern‐day energy research [79–85]. An outstanding result has been reported by Wang et al.…”

Section: Choice Of Polymer and Their Functionalizationmentioning

confidence: 87%

Polymer Based Functional Materials: A New Generation Photo‐active Candidate for Electrochemical Application

2022

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This article reviews the successive development of photo-assisted electrochemical performances using functionalized polymer materials. The photoelectrochemical technologies have already been well-established as a major tool for generating renewable energy harvesting solar power. In this regard, the research on the generation of new photoactive polymer supported units has drawn remarkable attention to improve the power conversion output and build up low-cost advanced devices. So, starting from fundamental working principle, we have tried to overview comprehensively the key features of most of these studies, which involve the tactical schemes behind the appropriate selection of different substituents to functionalize the polymer skeleton to achieve an optimal bandgap, challenges faced specially in the index of performance in post synthetic phase, the possible routes to overcome the hurdle, so that it can harvest photons matched with the solar spectrum and of course their relevance in the broad range of application window. Apart from photovoltaic solar cell application, the idea has been logically extended to cover highly selective photoelectrochemical sensing devices,where we have disclosed briefly the role of polymers in designing innovative biosensors, the trend of development along with specific illustrative examples, and some of their successful utilization in real time assay. The overall description is entirely focused on how these strategies have emerged from the background concepts and finally shaped to a viable and significant outcome.

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“…The noise current in OPDs includes the intrinsic noise current and the extrinsic noise current such as injection current. Various approaches have been developed to reduce the noise current in OPDs, including reducing the leakage current using a thicker photoactive layer, morphological engineering of the organic photoactive layer, [ 33 ] and suppressing charge injection current. The noise current in OPDs can be reduced using a thicker photoactive layer to increase the device resistance and prevent the pinholes in the photoactive layer.…”

Section: Advances In High‐performance Opdsmentioning

confidence: 99%

Recent Advances in Solution‐Processable Organic Photodetectors and Applications in Flexible Electronics

Lan

Lee

Zhu

2021

Advanced Intelligent Systems

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Organic photodetectors (OPDs) are promising for applications in flexible electronics due to their advantages of excellent photodetection performance, cost-effective solution-fabrication capability, flexible device design, and adaptivity to manufacturability. This review outlines the recent advances in the development of high-performance OPDs and their applications in flexible electronics. The approaches to developing different noise reduction methods, filter-free spectral selective detection, flexible OPDs, and scale-up production of flexible OPDs through solution-fabrication processes are discussed. Applications of the OPD technology ultimately result in the materialization of wearable units, flexible and compact information sensors at commercially viable costs, including wearable health self-monitoring devices, flexible optical communication systems, and flexible large-area image sensors.

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Dark current reduction strategies using edge-on aligned donor polymers for high detectivity and responsivity organic photodetectors

Abstract: The difluorobenzene-incorporated polymer showed strong ordering in edge-on mode, resulting in a significant reduction in the leakage current, and thus PFBT2OBT:PC70BM devices showed highly improved detectivity of over 1013 Jones at −2V.

Cited by 34 publications

References 56 publications

Improved Performance of Quantum‐Dot Photodetectors Using Cheap and Environmentally Friendly Polyethylene Glycol

Improved Performance of Quantum‐Dot Photodetectors Using Cheap and Environmentally Friendly Polyethylene Glycol

Polymer Based Functional Materials: A New Generation Photo‐active Candidate for Electrochemical Application

Recent Advances in Solution‐Processable Organic Photodetectors and Applications in Flexible Electronics

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