| 1. |
- Langer, Judith, et al.
(författare)
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Present and Future of Surface-Enhanced Raman Scattering
- 2020
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 14:1, s. 28-117
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Forskningsöversikt (refereegranskat)abstract
- The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article. ©
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| 2. |
- Almora, Osbel, et al.
(författare)
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Device Performance of Emerging Photovoltaic Materials (Version 1)
- 2020
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Emerging photovoltaics (PVs) focus on a variety of applications complementing large scale electricity generation. Organic, dye-sensitized, and some perovskite solar cells are considered in building integration, greenhouses, wearable, and indoor applications, thereby motivating research on flexible, transparent, semitransparent, and multi-junction PVs. Nevertheless, it can be very time consuming to find or develop an up-to-date overview of the state-of-the-art performance for these systems and applications. Two important resources for recording research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley–Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield is included as an analysis parameter among state-of-the-art emerging PVs.
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| 3. |
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| 4. |
- Gillett, Alexander J., et al.
(författare)
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The role of charge recombination to triplet excitons in organic solar cells
- 2021
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Ingår i: Nature. - : NATURE PORTFOLIO. - 0028-0836 .- 1476-4687. ; 597:7878, s. 666-
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Tidskriftsartikel (refereegranskat)abstract
- The use of non-fullerene acceptors (NFAs) in organic solar cells has led to power conversion efficiencies as high as 18%(1). However, organic solar cells are still less efficient than inorganic solar cells, which typically have power conversion efficiencies of more than 20%(2). A key reason for this difference is that organic solar cells have low open-circuit voltages relative to their optical bandgaps(3), owing to non-radiative recombination(4). For organic solar cells to compete with inorganic solar cells in terms of efficiency, non-radiative loss pathways must be identified and suppressed. Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; in the benchmark PM6:Y6 blend(5), this fraction reaches 90%, reducing the open-circuit voltage by 60 mV. We prevent recombination via this non-radiative channel by engineering substantial hybridization between the NFA triplet excitons and the spin-triplet charge-transfer excitons. Modelling suggests that the rate of back charge transfer from spin-triplet charge-transfer excitons to molecular triplet excitons may be reduced by an order of magnitude, enabling re-dissociation of the spin-triplet charge-transfer exciton. We demonstrate NFA systems in which the formation of triplet excitons is suppressed. This work thus provides a design pathway for organic solar cells with power conversion efficiencies of 20% or more. A substantial pathway for energy loss in organic solar cells may be suppressed by engineering hybridization between non-fullerene acceptor triplet excitons and spin-triplet charge transfer excitons.
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| 5. |
- McCuskey, Samantha R., et al.
(författare)
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Current Progress of Interfacing Organic Semiconducting Materials with Bacteria
- 2022
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 122:4, s. 4791-4825
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Forskningsöversikt (refereegranskat)abstract
- Microbial bioelectronics require interfacing microorganisms with electrodes. The resulting abiotic/biotic platforms provide the basis of a range of technologies, including energy conversion and diagnostic assays. Organic semiconductors (OSCs) provide a unique strategy to modulate the interfaces between microbial systems and external electrodes, thereby improving the performance of these incipient technologies. In this review, we explore recent progress in the field on how OSCs, and related materials capable of charge transport, are being used within the context of microbial systems, and more specifically bacteria. We begin by examining the electrochemical communication modes in bacteria and the biological basis for charge transport. Different types of synthetic organic materials that have been designed and synthesized for interfacing and interrogating bacteria are discussed next, followed by the most commonly used characterization techniques for evaluating transport in microbial, synthetic, and hybrid systems. A range of applications is subsequently examined, including biological sensors and energy conversion systems. The review concludes by summarizing what has been accomplished so far and suggests future design approaches for OSC bioelectronics materials and technologies that hybridize characteristic properties of microbial and OSC systems.
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| 6. |
- Nilsson, Peter, 1970-
(författare)
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Conjugated polyelectrolytes : conformation sensitive optical probes for the recording of biological processes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The physical properties of conjugated polymers can be utilized for a wide range of biosensors. For instance, the conformational flexibility fouud in conjugated polyelectrolytes, allows direct connection between the geometry of chains and the resulting electronic structure and optical processes, since the extension of the π-conjugated system is distorted by conformational changes of the polyelectrolyte backbone. The biosensors presented in this thesis are utilizing conformational changes of conjugated polyelectrolytes for the detection of biomolecular processes, such as biospecific interactions and conformational changes of biomolecules. The methodology have been used for the detection of DNA-hybridization, single nucleotide polymorphism (SNP) in DNA, conformational alterations of synthetic peptides, conformational alterations of Calmodulin and binding of Ca2+-activated Calmodulin (CaM) to Calcineurin, and amyloid fibril formation of amyloidogenic proteins.The method is based on non-covalent assembly of a conjugated polyelectrolyte and a biomolecule of interest. Upon exposure to a second biomolecule recognizing the first biomolecule or a conformational change of the first biomolecule, a conformational alteration of the polyelectrolyte backbone and a change in the electronic properties of the polyelectrolyte occurs, and these alterations can be detected by a change of the absorption or the fluorescence from the polyelectrolyte. Hence, conjugated polyelectrolytes can be used as novel conformation sensitive optical probes for the detection of several biological processes. The biomolecular interaction or the conformational changes of the biomolecule are reflected as an alteration of the geometry and the electronic structure of the bouud polyelectrolyte chains and are detected by absorption and emission. The present mechanism may be used for detection of a variety biomolecular processes, and the simplicity and the diversity of this methodology make it suitable for making inexpensive protein- and DNA-chips for rapid detection of biomolecular recognition.
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| 7. |
- Wang, Bing, et al.
(författare)
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Precisely Defined Conjugated Oligoelectrolytes for Biosensing and Therapeutics
- 2019
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 31:22
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Forskningsöversikt (refereegranskat)abstract
- Conjugated oligoelectrolytes (COEs) are a relatively new class of synthetic organic molecules with, as of yet, untapped potential for use in organic optoelectronic devices and bioelectronic systems. COEs also offer a novel molecular approach to biosensing, bioimaging, and disease therapy. Substantial progress has been made in the past decade at the intersection of chemistry, materials science, and the biological sciences developing COEs and their polymer analogues, namely, conjugated polyelectrolytes (CPEs), into synthetic systems with biological and biomedical utility. CPEs have traditionally attracted more attention in arenas of sensing, imaging, and therapy. However, the precisely defined molecular structures and interactions of COEs offer potential key advantages over CPEs, including higher reliability and fluorescence quantum efficiency, larger diversity of subcellular targeting strategies, and improved selectivity to biomolecules. Here, the unique-and sometimes overlooked-properties of COEs are discussed and the noticeable progress in their use for biological sensing, imaging, and therapy is reviewed.
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| 8. |
- Xie, Jiaqi, et al.
(författare)
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N-doping of nonfullerene bulk-heterojunction organic solar cells strengthens photogeneration and exciton dissociation
- 2022
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 10:36, s. 18845-18855
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Tidskriftsartikel (refereegranskat)abstract
- N-type doping of the bulk-heterojunction layer in nonfullerene organic solar cells allows to effectively ameliorate inferior electron transportation by filling traps and optimizing electron pathways, leading to a better balance of charge transport in device. This mechanism, however, provides an incomplete understanding of the stronger photogeneration, long-lived excitons and simultaneously increased short-circuit current density (JSC) and open-circuit voltage (VOC) that also benefit from the n-doping. Herein we investigate how molecular n-dopant impacts the optical characteristics, intermolecular packing behavior, charge carrier dynamics and photovoltaic performance in the nonfullerene-based blend. When incorporating a prototypical n-type dopant N-DMBI into a benchmark PM6:Y6 blend, the crystallization of PM6/Y6 is facilitated and the crystal coherence length is elongated, which is correlated with the optical absorbance enhancement. N-doping is unveiled to prolong exciton lifetime by retarding germinate recombination (GR) both at donor/acceptor (D/A) interfaces and within constituent domains by dilating interspace, reducing trap states and decreasing exciton binding energy. Despite slower interfacial charge transfer across the enlarged D/A interspace due to dopant intercalation, exciton dissociation remains highly effective due to the impeded interfacial GR. Consequently, the champion inverted cell at an optimal N-DMBI content delivers a decent efficiency of 15.34%, which is among the highest of the state-of-the art analogous PM6:Y6-based binary cells. Such improvement is largely ascribed to the concurrent increase of JSC (up to 26.41 mA cm−2) and VOC (up to 0.86 V) in comparison to the undoped device.
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| 9. |
- Yuan, Jianyu, et al.
(författare)
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Comparing the device physics, dynamics and morphology of polymer solar cells employing conventional PCBM and non-fullerene polymer acceptor N2200
- 2017
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Ingår i: Nano Energy. - : ELSEVIER SCIENCE BV. - 2211-2855 .- 2211-3282. ; 35, s. 251-262
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Tidskriftsartikel (refereegranskat)abstract
- Current all polymer solar cells still suffer from low fill factors (FF) and short-circuit current density (J(sc)) compared with the conventional polymer/fullerene system. Herein in this work, devices using PTP8 as the electron donor and [70]PCBM as well as widely used polymer N2200 as the electron acceptor were systematically studied and compared. The major loss mechanisms in the all polymer solar cells were investigated to understand their relatively lower performance than the PTP8/fullerene system. By performing in-depth analysis on ultrafast transient transmission spectroscopy results, we estimated that in PTP8/N2200 device nearly half of the charges recombine geminately, which is confirmed as the major factor hindering the device performance of all polymer solar cells compared with polymer/fullerene system. Through thorough morphology analysis, the low charge generation efficiency is attributed to the reduced crystallinity of N2200 in the blend film and the unfavorable face-to-edge orientation at the donor/acceptor heterojunction. Coupling these results with knowledge from efficient polymer/fullerene systems, the future design of new polymers can devote to increase the attraction between the pi face of donor and acceptor, leading to enhanced face-to-face orientation at the heterojunction, while maintaining a high pi-pi stacking order for each polymer.
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