| 1. |
- Svirelis, Justas, 1993, et al.
(författare)
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Stable trapping of multiple proteins at physiological conditions using nanoscale chambers with macromolecular gates
- 2023
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to detect and analyze single or few biological molecules is very important for understanding interactions and reaction mechanisms. Ideally, the molecules should be confined to a nanoscale volume so that the observation time by optical methods can be extended. However, it has proven difficult to develop reliable, non-invasive trapping techniques for biomolecules under physiological conditions. Here we present a platform for long-term tether-free (solution phase) trapping of proteins without exposing them to any field gradient forces. We show that a responsive polymer brush can make solid state nanopores switch between a fully open and a fully closed state with respect to proteins, while always allowing the passage of solvent, ions and small molecules. This makes it possible to trap a very high number of proteins (500-1000) inside nanoscale chambers as small as one attoliter, reaching concentrations up to 60 gL−1. Our method is fully compatible with parallelization by imaging arrays of nanochambers. Additionally, we show that enzymatic cascade reactions can be performed with multiple native enzymes under full nanoscale confinement and steady supply of reactants. This platform will greatly extend the possibilities to optically analyze interactions involving multiple proteins, such as the dynamics of oligomerization events.
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| 2. |
- Gugole, Marika, 1993, et al.
(författare)
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Comparison of Electrodeposited and Sputtered Tungsten Trioxide Films for Inorganic Electrochromic Nanostructures
- 2023
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Ingår i: ACS Applied Optical Materials. - : American Chemical Society (ACS). - 2771-9855 .- 2574-0962. ; 1:2, s. 558-568
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic materials and their implementation with structural colors are currently being intensely researched because of their promising applications as non-emissive display devices utilizing ambient light. In particular, several fully inorganic devices that rely on electrochromic tungsten trioxide (WO3) have been presented. For preparing nanoscale films of this material, sputtering is the most established technique, but electrodeposition has recently been shown to be capable of achieving exceptionally high electro-optical modulation contrast without the need for expensive equipment. In this work, we investigate the possibilities of electrodeposited WO3 and present a systematic comparison with sputtered WO3 with respect to performance in electrochromic devices. Importantly, we show that “ultralarge” electro-optical modulation (∼95% change in transmission) is possible for both types of films. However, it is only the sputtered films that enable such high contrast in a stable electrolyte such as LiClO4 in propylene carbonate. The electrodeposited films are less uniform and difficult to make thicker than ∼500 nm. We find no evidence that the electrochromic properties of the electrodeposited WO3 are intrinsically better than those of sputtered WO3. However, the electrodeposited films are much rougher and/or porous on the nanoscale, which increases the switching speed considerably. We conclude that electrodeposited WO3 is mainly useful in applications in which high contrast is not essential while switching speed is. As an example, we present the first electrodeposited WO3 integrated with structural colors by sandwiching the material between two metal films. By electrical control, the reflective colors can then be tuned at least one order of magnitude faster (a few seconds) than previously reported while having fair color quality and without any loss of brightness.
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| 3. |
- Gugole, Marika, 1993, et al.
(författare)
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Electrochromic Inorganic Nanostructures with High Chromaticity and Superior Brightness
- 2021
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 21:10, s. 4343-4350
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of actively controlling structural colors has recently attracted a lot of attention, in particular for new types of reflective displays (electronic paper). However, it has proven challenging to achieve good image quality in such devices, mainly because many subpixels are necessary and the semitransparent counter electrodes lower the total reflectance. Here we present an inorganic electrochromic nanostructure based on tungsten trioxide, gold, and a thin platinum mirror. The platinum reflector provides a wide color range and makes it possible to "reverse"the device design so that electrolyte and counter electrode can be placed behind the nanostructures with respect to the viewer. Importantly, this makes it possible to maintain high reflectance regardless of how the electrochemical cell is constructed. We show that our nanostructures clearly outperform the latest commercial color e-reader in terms of both color range and brightness.
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| 4. |
- Gugole, Marika, 1993, et al.
(författare)
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High-Contrast Switching of Plasmonic Structural Colors: Inorganic versus Organic Electrochromism
- 2020
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 7:7, s. 1762-1772
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonic structural colors have recently received a lot of attention. For many applications there is a need to actively tune the colors after preparing the nanostructures, preferably with as strong changes in the optical response as possible. However, to date, there is a lack of systematic investigations on how to enhance contrast in electrically induced color modulation. In this work we implement electrochromic films with plasmonic metasurfaces and compare systematically organic and inorganic materials, with the primary aim to maximize brightness and contrast in a reflective color display. We show nanostructures with good chromaticity and high polarization-insensitive reflectivity (-90%) that are electrochemically stable in a nonaqueous solvent. Methods are evaluated for reliable and uniform electropolymerization of the conductive polymer dimethylpropylenedioxythiophene (PProDOTMe2) on gold. The resulting organic films are well-described by Lambert-Beer formalism, and the highest achievable contrast is easily determined in transmission mode. The optical properties of the inorganic option (WO3) require full Fresnel models due to thin film interference, and the film thickness must be carefully selected in order to maintain the chromaticity of the metasurfaces. Still, the optimized fully inorganic device reaches the highest contrast of approximately 60% reflectivity change for all primary colors. The switching time is about an order of magnitude faster for the organic films (hundreds of ms). The bistability is very long (hours) for the inorganic devices and comparable for the polymers, which makes the power consumption essentially zero for maintaining the same state. Finally, we show that switching of the primary colors in optimized devices (both organic and inorganic) provides almost twice as high brightness and contrast compared to existing reflective display technologies with RGB subpixels created by color filters.
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| 5. |
- Gugole, Marika, 1993, et al.
(författare)
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Optimizing electrochromism for plasmonic electronic paper: Inorganic vs organic
- 2019
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Ingår i: International Conference on Metamaterials, Photonic Crystals and Plasmonics. - 2429-1390. ; , s. 760-761
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Konferensbidrag (refereegranskat)abstract
- The combination of plasmonic nanostructures and electrochromic materials for dynamic color generation has been of interest in recent years due to the possibility to make reflective displays in full color with extremely low power consumption compared to emissive displays. We show a comparison between two electrochromic materials, tungsten trioxide (inorganic) and PProDOTMe2 (organic), for electrical modulation of the resonantly reflected light from plasmonic nanostructures. The comparison focuses on achievable contrast, switching speed, coloration memory and power consumption.
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| 6. |
- Gugole, Marika, 1993, et al.
(författare)
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Plasmonic Electronic Paper
- 2021
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Ingår i: International Conference on Metamaterials, Photonic Crystals and Plasmonics. - 2429-1390.
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Konferensbidrag (refereegranskat)abstract
- We work on developing reflective displays (electronic paper) in color by combining plasmonic nanostructures and electrochromic materials. The main motivation is to save energy in comparison with emissive displays.
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| 7. |
- Olsson, Oliver, 1993, et al.
(författare)
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Electrochromic Passive Matrix Display Utilizing Diode-Like Redox Reactions on Indium-Tin-Oxide
- 2024
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Ingår i: Advanced Engineering Materials. - 1527-2648 .- 1438-1656. ; 26:8
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Tidskriftsartikel (refereegranskat)abstract
- Recent years have shown many advances in the development of tunable structural colors by combining nanostructures with electrochromic materials. One main goal is to develop energy saving color displays that rely on ambient light instead of being emissive. However, all displays need to be pixelated to show arbitrary images and few studies have addressed the challenge of preparing and controlling individual electrochromic pixels. Herein, a very simple method to reach this milestone by using passive matrix addressing is presented, which requires no additional electronic components in the pixels. It is shown that the common transparent conductor indium tin oxide (ITO) in non-aqueous electrolytes exhibits the diode-like behavior (threshold in voltage in relation to current and coloration) necessary to prevent significant cross-talk between pixels. The chemical nature of the redox activity that enables this behavior is attributed to omnipresent oxygen and the formation of superoxide ions. Additionally, it is shown that a gel-like electrolyte can be prepared by optical lithography, which makes the concept compatible with patterning of pixels at high resolution. This method for preparing pixelated displays should be compatible with practically any type of electrochromic surface in both reflective and transmissive configurations. Also, the counter electrode maintains excellent transparency since it simply consists of ITO. The results should prove very useful as the research field of tunable structural colors moves from proof-of-concept to real devices. A method for realizing pixelated electrochromic devices using passive matrix addressing is presented. This is achieved simply by using indium-tin-oxide (ITO) as the counter electrode, which creates a diode-like current response in a stable electrolyte.image (c) 2024 WILEY-VCH GmbH
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| 8. |
- Olsson, Oliver, 1993, et al.
(författare)
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Enhanced electrochromic switching contrast in the blue by 3,4-propylenedioxypyrrole - Implementation on structural colors
- 2023
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Ingår i: Nanophotonics. - : Walter de Gruyter GmbH. - 2192-8614 .- 2192-8606. ; 12:8, s. 1591-1599
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in nanofabrication technologies have enabled new ways to produce structural colors. By combining nanofabrication methods, it is possible to integrate electrochromic materials with the nanostructures, which enable electrical tuning of the colors and thus new types of reflective displays. Previous work has shown high quality colors and high switching contrast in general. However, so far the intensity modulation has always been more limited in the blue. In this work we prepare blue structural colors and synthesize films of an electrochromic polymer (PProDOP) that is optimized for high contrast in this spectral region. A protocol for electropolymerization of PProDOP on gold surfaces is presented. The polymer films are shown to follow Lambert-Beer behavior and can provide up to 75% contrast (difference in transmittivity). On blue nanostructures, the reflectivity can be modulated with a contrast of 50%, which is a considerable improvement in comparison with previous work. The results presented here should be useful for electrochromic or other electro-optical devices operating in the blue spectral region.
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| 9. |
- Xiong, Kunli, et al.
(författare)
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Video Speed Switching of Plasmonic Structural Colors with High Contrast and Superior Lifetime
- 2021
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 33:41
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Tidskriftsartikel (refereegranskat)abstract
- Reflective displays or "electronic paper" technologies provide a solution to the high energy consumption of emissive displays by simply utilizing ambient light. However, it has proven challenging to develop electronic paper with competitive image quality and video speed capabilities. Here, the first technology that provides video speed switching of structural colors with high contrast over the whole visible is shown. Importantly, this is achieved with a broadband-absorbing polarization-insensitive electrochromic polymer instead of liquid crystals, which makes it possible to maintain high reflectivity. It is shown that promoting electrophoretic ion transport (drift motion) improves the switch speed. In combination with new nanostructures that have high surface curvature, this enables video speed switching (20 ms) at high contrast (50% reflectivity change). A detailed analysis of the optical signal during switching shows that the polaron formation starts to obey first order reaction kinetics in the video speed regime. Additionally, the system still operates at ultralow power consumption during video speed switching (<1 mW cm(-2)) and has negligible power consumption (<1 mu W cm(-2)) in bistability mode. Finally, the fast switching increases device lifetime to at least 10(7) cycles, an order of magnitude more than state-of-the-art.
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| 10. |
- Brooke, Robert, 1989-, et al.
(författare)
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All-Printed Multilayers and Blends of Poly(dioxythiophene) Derivatives Patterned into Flexible Electrochromic Displays
- 2023
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Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:2
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Tidskriftsartikel (refereegranskat)abstract
- Low-cost, flexible and thin display technology is becoming an interesting field of research as it can accompany the wide range of sensors being developed. Here, the synthesis of poly(dimethylpropylene-dioxythiophene) (PProDOT-Me2) by combining vapor phase polymerization and screen printing is presented. A multilayer architecture using poly(3,4-ethylenedioxythiophene) (PEDOT) and PProDOT-Me2 to allow for electrochromic switching of PProDOT-Me2, thereby eliminating the need for a supporting transparent conductive (metal oxide) layer is introduced. Furthermore, the technology is adapted to a blended architecture, which removes the additional processing steps and results in improved color contrast (∆E* > 25). This blend architecture is extended to other conductive polymers, such as PEDOT and polypyrrole (PPy), to highlight the ability of the technique to adjust the color of all-printed electrochromic displays. As a result, a green color is obtained when combining the blue and yellow states of PEDOT and PPy, respectively. This technology has the potential to pave the way for all-printed multicolored electrochromic displays for further utilization in printed electronic systems in various Internet of Things applications. © 2022 The Authors.
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| 11. |
- Olsson, Oliver, 1993
(författare)
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Conjugated polymers on plasmonic metasurfaces for high contrast electronic paper in color
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Electronic paper is the collective name of displays that, instead of emitting light, reflect the ambient light. These displays are known to have good readability in daylight and very low power consumption. However, there is a lack of electronic paper in color with high contrast and the ability to achieve video speed. This work presents that by utilizing a plasmonic metasurface, highly reflective subpixels in red, green, and blue can be achieved. Electrochromic materials are used to modulate the reflectivity, turning the pixels ON and OFF. Conjugated polymers, such as polypyrrole, polyethylenedioxythiopene (PEDOT), and poly(dimethylpropylenedioxythiophene) (PProDOT-Me2), are known for their electrochromic properties and are evaluated for their optical performance in organic solvent on a thin gold film. The optical contrast of a film depends on both the polymer and the thickness, and it is found that by measuring the optical extinction in both the bleached (transmissive) state and the colored (absorbing) state of an arbitrary thickness, the maximum contrast of the polymer can be extracted by using the ratio of the optical extinction values. PProDOT-Me2 is shown to have the highest maximum contrast and is electropolymerized on top of the red, green, and blue plasmonic metasurfaces with an excellent optical contrast of 50%-60%. Tungsten oxide is evaluated as an inorganic electrochromic option and compared with PProDOTMe2— Its optical contrast is around 60% for all samples. The bistability is in favor of tungsten oxide, which showed little to no change after 1000 s, while PProDOT-Me2 has a slight change after 100 s. On the contrary, PProDOT-Me2 had a switching time of less than two seconds, while tungsten oxide had ten times higher. For PProDOT-Me2, the distance between the electrodes with the polymer and the counter electrode influences the switching time. Reducing this distance below 1 mm and using a suitable solvent resulted in a time between 10-50 ms, i.e. in the video speed regime. By producing a positive curvature on the electrode and deposit the polymer, it is also possible to keep the contrast high with video speed. Using fast pulses also facilitated to switch the polymer from bleached to colored more than 10 million times with low degradation using an ionic liquid. The previously reported number of switches is one order of magnitude less.
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| 12. |
- Olsson, Oliver, 1993
(författare)
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Electronic paper in color by electrochromic materials and plasmonics
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The most common display today is emissive. It produces its own light and emits it to the viewer's eye. A reflective display, also known as electronic paper, uses ambient light and reflects it to the viewer, just like a newspaper. Electronic paper has some advantages over emissive displays such as: lower power consumption and readability in sunlight. Today, electronic papers in color lack a desirable color gamut - the colors look bad. The purpose of this thesis is to investigate how structural colors, plasmonics and electrochromics can be used to increase the optical performance of electronic paper in color. By using structural colors (metal-insulator-metal) and plasmonics, we could create highly reflective color pixels. The pixels could be made to turn ON and OFF using electrochromic materials. In this thesis, conjugated polymers (PProDOT-Me2 and PProDOP) or tungsten oxide were employed. The reflection difference between the ON and OFF states was 60%. This was better than previously reported values for other electrochromic materials. If the electrochromic material instead was incorporated into the nanostructure (metal-electrochromics-metal), applying a voltage would then alter the color of the pixel. If tungsten oxide was used inside the structure, the color of one pixel could change, but it would not be able to span the whole visible spectra. If, instead, the conjugated polymer (PT34bT) was used inside the structure, the whole visible spectra could be accessed with one pixel. To create a real display, it is not enough to have one pixel that can change color. Millions of pixels in a grid are necessary. This poses a problem since each pixel needs to be individually contacted. This can be overcome by using a matrix configuration such as a passive matrix (PM) or an active matrix (AM). This thesis investigates both these configurations. PM requires the color change to be strongly non-linear with the applied voltage. It must have memory such as hysteresis. This effect can be incorporated by utilizing an indium-tin-oxide electrode as a counter electrode to a metal working electrode coated with a conjugated polymer as electrochromic material. To avoid crosstalk between pixels, a photo patterned electrolyte was used. Commercial thin-film transistor arrays were used for AM configuration. The red, green, and blue nanostructures were deposited on the array. The conjugated polymer PProDOT-Me2 is synthesized directly on individual pixels and switched without crosstalk.
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| 13. |
- Rossi, Stefano, et al.
(författare)
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Dynamically Tuneable Reflective Structural Coloration with Electroactive Conducting Polymer Nanocavities
- 2021
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 33:49
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic control of structural colors across the visible spectrum with high brightness has proven to be a difficult challenge. Here, this is addressed with a tuneable reflective nano-optical cavity that uses an electroactive conducting polymer (poly(thieno[3,4-b]thiophene)) as spacer layer. Electrochemical doping and dedoping of the polymer spacer layer provides reversible tuning of the cavity's structural color throughout the entire visible range and beyond. Furthermore, the cavity provides high peak reflectance that varies only slightly between the reduced and oxidized states of the polymer. The results indicate that the polymer undergoes large reversible thickness changes upon redox tuning, aided by changes in optical properties and low visible absorption. The electroactive cavity concept may find particular use in reflective displays, by opening for tuneable monopixels that eliminate limitations in brightness of traditional subpixel-based systems.
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| 14. |
- Xiong, Kunli, 1987, et al.
(författare)
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Video-Rate Switching of High-Reflectivity Hybrid Cavities Spanning All Primary Colors
- 2023
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 35:31
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Tidskriftsartikel (refereegranskat)abstract
- Dynamically tunable reflective structural colors are attractive for reflective displays (electronic paper). However, it is challenging to tune a thin layer of structural color across the full red-green-blue (RGB) basis set of colors at video rates and with long-term stability. In this work, this is achieved through a hybrid cavity built from metal-insulator-metal (MIM) "nanocaves" and an electrochromic polymer (PProDOTMe(2)). The reflective colors are modulated by electrochemically doping/dedoping the polymer. Compared with traditional subpixel-based systems, this hybrid structure provides high reflectivity (>40%) due to its "monopixel" nature and switches at video rates. The polymer bistability helps deliver ultralow power consumption (& AP;2.5 mW cm(-2)) for video display applications and negligible consumption (& AP;3 & mu;W cm(-2)) for static images, compatible with fully photovoltaic powering. In addition, the color uniformity of the hybrid material is excellent (over cm(-2)) and the scalable fabrication enables large-area production.
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