| 1. |
- Gugole, Marika, 1993, et al.
(författare)
-
Electrochromic Inorganic Nanostructures with High Chromaticity and Superior Brightness
- 2021
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 21:10, s. 4343-4350
-
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.
|
|
| 2. |
- Blake, Jolie, 1986, et al.
(författare)
-
Scalable Reflective Plasmonic Structural Colors from Nanoparticles and Cavity Resonances – the Cyan-Magenta-Yellow Approach
- 2022
-
Ingår i: Advanced Optical Materials. - : Wiley. - 2195-1071 .- 2162-7568. ; 10:13
-
Tidskriftsartikel (refereegranskat)abstract
- Plasmonic metasurfaces for color generation are emerging as important components for next generation display devices. Fabricating bright plasmonic colors economically and via easily scalable methods, however, remains difficult. Here, the authors demonstrate an efficient and scalable strategy based on colloidal lithography to fabricate silver-based reflective metal–insulator–nanodisk plasmonic cavities that provide a cyan-magenta-yellow (CMY) color palette with high relative luminance. With the same basic structure, they exploit different mechanisms to efficiently produce a complete subtractive color palette. Finite-difference time-domain simulations reveal that these mechanisms include gap surface plasmon modes for thin insulators and hybridized modes between disk plasmons and Fabry–Pérot modes for thicker systems. To produce yellow hues, they take advantage of higher-energy gap surface plasmon modes to allow resonance dips in the blue spectral region for comparably large nanodisks, thereby circumventing difficult fabrication of nanodisks less than 80 nm. It is anticipated that incorporation of these strategies can reduce fabrication constraints, produce bright saturated colors, and expedite large-scale production.
|
|
| 3. |
- Rossi, Stefano, et al.
(författare)
-
Dynamically Tuneable Reflective Structural Coloration with Electroactive Conducting Polymer Nanocavities
- 2021
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 33:49
-
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.
|
|
| 4. |
- Rossi, Stefano, 1993-
(författare)
-
Reflective structural colors and their actuation using electroactive conducting polymers
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The integration of inorganic photonic nanostructures with organic materials opens new possibilities to dynamically modify the optical response of photonic devices. This thesis focuses on how to generate efficient reflective structural colors and tune them in combination with a conducting polymer (CP). The main technological interest lies in color reflective displays, devices with ultralow power consumption that work with reflected environmental light. The main challenge is to obtain dynamic color tunability while maintaining good chromaticity and brightness. We first studied how to make efficient reflective structural colors and focused on highly reflective optical nanocavities based on metal-insulator-metal (MIM), combining the Fabry-Pérot effect and a broadband absorber. We demonstrated a full color palette by changing the spacer thickness and proposed different configurations to improve the chromaticity and reproduce black. We also explored subtractive coloration with a cyan-yellow-magenta (CYM) system to increase the relative luminance for reflective displays. We covered the CYM spectrum by combining plasmonic nanodisks with optical nanocavities, using a scalable nanofabrication method based on colloidal lithography. Subsequently, we modified our optical nanocavities by replacing the dielectric spacer with a low bandgap electroactive CP, polythieno[3,4 b]thiophene(pT34bT), to obtain active color tunability. By integrating the optical nanocavities in an electrochemical cell, we proved tunability of the reflected color across all the visible spectrum with low operating voltages and similar reflectance values for all the oxidation states. Those cavities can be considered a proof of principle for the development of tunable monopixels. In addition, we explored vapour phase polymerization (VPP) as an alternative deposition method with direct patterning possibilities by UV-exposure of the precursor oxidant film. We developed optical reflective nanocavities with a spacer based on poly[3,4-ethylenedioxythiophene]:Tosylate (PEDOT:Tos) on metal mirrors, generating color images by different UV exposures. We showed the feasibility of generating images by using a UV photomask with different contrasts. Those cavities could also be switched in color by electrochemical tuning in an electrolyte, reaching different electrochromic states. This method has the potential to be extended to other types of polymers and to be used for display technologies.
|
|
| 5. |
- Xiong, Kunli, 1987, et al.
(författare)
-
Video-Rate Switching of High-Reflectivity Hybrid Cavities Spanning All Primary Colors
- 2023
-
Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 35:31
-
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.
|
|
