A Universal Method to Produce Low–Work Function Electrodes for Organic Electronics

Zhou, Yinhua; Fuentes-Hernández, Canek; Shim, Jae Kun; Meyer, Jens; Giordano, Anthony J.; Li, Hong; Winget, Paul; Papadopoulos, Theodoros A.; Cheun, Hyeunseok; Kim, Jungbae; Fenoll, Mathieu; Dindar, Amir; Haske, Wojciech; Najafabadi, Ehsan; Khan, Talha M.; Sojoudi, Hossein; Barlow, Stephen; Graham, Samuel; Brédas, Jean Luc; Marder, Seth R.; Kahn, Antoine; Kippelen, Bernard

doi:10.1126/science.1218829

Cited by 1,909 publications

(2,031 citation statements)

References 51 publications

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“…The low work function of 80% ethoxylated polyethylenimine (PEIE)-modified indium tin oxide (ITO) favors the collection of electrons at the cathode. 21 MoO 3 is used as the electron-blocking layer at the anode and matches the highest occupied molecular orbital (HOMO) level of the polymer. 22 The near-infrared absorbing material used in the fabrication of the BHJ photodiode is a polymer comprised of an exocyclic olefin subsituted 4H-cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) donor and a 2,1,3-benzoselenadiazole acceptor (CPDT-alt-BSe) (with a number-average molecular weight M n = 10 kg mol −1 and dispersity (Đ = 2.9).…”

Section: Resultsmentioning

confidence: 99%

Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes

Yao

London

et al. 2017

ACS Appl. Mater. Interfaces

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Bulk heterojunction photodiodes are fabricated using a new donor−acceptor polymer with a near-infrared absorption edge at 1.2 μm, achieving a detectivity up to 10 12 Jones at a wavelength of 1 μm and an excellent linear dynamic range of 86 dB. The photodiode detectivity is maximized by operating at zero bias to suppress dark current, while a thin 175 nm active layer is used to facilitate charge collection without reverse bias. Analysis of the temperature dependence of the dark current and spectral response demonstrates a 2.8-fold increase in detectivity as the temperature was lowered from 44 to −12°C , a relatively small change when compared to that of inorganic-based devices. The near-infrared photodiode shows a switching speed reaching up to 120 μs without an external bias. An application using our NIR photodiode to detect arterial pulses of a fingertip is demonstrated.

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Section: Resultsmentioning

confidence: 99%

Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes

Yao

London

et al. 2017

ACS Appl. Mater. Interfaces

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“…In particular, the PhNBr‐based devices yielded the highest PCE of 5.00%, an ≈27% improvement compared with the Ca/Al reference device (PCE = 3.94%) 22. Since the TrNBr, PhNBr, and TPANBr systems show similar interfacial properties (e.g., surface morphology, interfacial energy, and thickness), the apparent distinction between TrNBr and the other two material systems (PhNBr and TPANBr) can be explained based on the higher ion density (more hydrophilic part) of PhNBr and TPANBr than TrNBr, which is probably capable of providing more electron injection channels than that of TrNBr 18, 33…”

Section: Resultsmentioning

confidence: 99%

Understanding the Light Soaking Effects in Inverted Organic Solar Cells Functionalized with Conjugated Macroelectrolyte Electron‐Collecting Interlayers

Xia

et al. 2015

Advanced Science

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Three kinds of charged star‐shaped conjugated macroelectrolytes, named as PhNBr, TPANBr, and TrNBr, are synthesized as electron‐collecting interlayers for inverted polymer solar cells (i‐PSCs). Based on these well‐defined structured interlayer materials, the light soaking (LS) effect observed in i‐PSCs was studied systematically and accurately. The general character of the LS effect is further verified by studying additional i‐PSC devices functionalized with other common interlayers. The key‐role of UV photons was confirmed by electrochemical impedance spectroscopy and electron‐only devices. In addition, the ultraviolet photoelectron spectroscopy measurements indicate that the work function of the indium tin oxide (ITO)/interlayer cathode is significantly reduced after UV treatment. In these i‐PSC devices the LS effect originates from the adsorbed oxygen on the ITO substrates when oxygen plasma is used; however, even a small amount of oxygen from the ambient is also enough for triggering the LS effect, albeit with a weaker intensity. Our results suggest that the effect of adsorbed oxygen on ITO needs to be considered with attention while preparing i‐PSCs. This is an important finding that can aid the large‐scale manufacturing of organic solar cells via printing technologies, which do not always ensure the full protection of the device electrode substrates from oxygen.

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“…As an alternative to conjugated polymer CILs, non‐conjugated polyelectrolytes (NCPEs) with charged ionic groups in their structures can also be employed to tune WFs of cathodes so as to reduce interfacial energy barriers and increase the built‐in potential of inverted devices 122, 123. Representative NCPE interlayer materials such as polyethyleneimine (PEI), polyallylamine (PAA), and ethoxylated polyethyleneimine (PEIE) have been directly used as CILs for OSCs 122, 123, 124.…”

Section: Electron‐transporting Materials As Cilsmentioning

confidence: 99%

“…Representative NCPE interlayer materials such as polyethyleneimine (PEI), polyallylamine (PAA), and ethoxylated polyethyleneimine (PEIE) have been directly used as CILs for OSCs 122, 123, 124. The use of solution‐processed PEI layer can drastically reduce the WF of ITO from 4.8 to 4.0 eV, which is originated from the strong electrostatic self‐assembled dipoles created by the presence of protonated amines within the ITO/PEI cathode.…”

Section: Electron‐transporting Materials As Cilsmentioning

confidence: 99%

Interfacial Materials for Organic Solar Cells: Recent Advances and Perspectives

2016

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Organic solar cells (OSCs) have shown great promise as low‐cost photovoltaic devices for solar energy conversion over the past decade. Interfacial engineering provides a powerful strategy to enhance efficiency and stability of OSCs. With the rapid advances of interface layer materials and active layer materials, power conversion efficiencies (PCEs) of both single‐junction and tandem OSCs have exceeded a landmark value of 10%. This review summarizes the latest advances in interfacial layers for single‐junction and tandem OSCs. Electron or hole transporting materials, including metal oxides, polymers/small‐molecules, metals and metal salts/complexes, carbon‐based materials, organic‐inorganic hybrids/composites, and other emerging materials, are systemically presented as cathode and anode interface layers for high performance OSCs. Meanwhile, incorporating these electron‐transporting and hole‐transporting layer materials as building blocks, a variety of interconnecting layers for conventional or inverted tandem OSCs are comprehensively discussed, along with their functions to bridge the difference between adjacent subcells. By analyzing the structure–property relationships of various interfacial materials, the important design rules for such materials towards high efficiency and stable OSCs are highlighted. Finally, we present a brief summary as well as some perspectives to help researchers understand the current challenges and opportunities in this emerging area of research.

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A Universal Method to Produce Low–Work Function Electrodes for Organic Electronics

Cited by 1,909 publications

References 51 publications

Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes

Temperature-Dependent Detectivity of Near-Infrared Organic Bulk Heterojunction Photodiodes

Understanding the Light Soaking Effects in Inverted Organic Solar Cells Functionalized with Conjugated Macroelectrolyte Electron‐Collecting Interlayers

Interfacial Materials for Organic Solar Cells: Recent Advances and Perspectives

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