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- Mun, Seungsoo, et al.
(författare)
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Reconfigurable dual-mode optical encryption enabled by block copolymer photonic crystal with micro-imprinted holographic metasurface
- 2023
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Ingår i: Materials Today. - : ELSEVIER SCI LTD. - 1369-7021 .- 1873-4103. ; 70, s. 44-56
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Tidskriftsartikel (refereegranskat)abstract
- Dual-mode optical encryption based on holographic metasurfaces and color components is of great attraction because of their enhanced information security and storage; however, the realization of independently as well as reversibly encodable holographic metasurfaces and color components remains unreported. Herein, we present reconfigurable dual-mode encryptions of structural colors (SC) and holograms, achieved through stimuli-responsive block copolymer (BCP) photonic crystals (PCs) with micro-imprinted holographic metasurfaces. Holographic images appear when the micro-imprinted BCP PCs, consisting of self-assembled alternating lamellae of two dielectrics, are exposed to an incident laser. A characteristic SC develops in the visible range when the imprinted film is immersed in a liquid agent that can swell one of the dielectrics, allowing for dual-mode holographic and SC encodings in the solid and liquid states, respectively. The dual-mode optical encoding is reconfigured. The holographic image can be erased and replaced with another micropattern, while preserving the SC. Moreover, an SC, set by crosslinking of the swellable lamellae, is reset by chemical de-crosslinking and subsequent transient re-crosslinking, enabling the SC reconfigurability of the BCP PC film. A prototype of a high-security reconfigurable dual encryption has been developed, wherein true information is decrypted when holographic passwords are confirmed with full-color visible SC passwords.
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| 2. |
- Park, Taehyun, et al.
(författare)
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Ionoelastomer electrolytes for stretchable ionic thermoelectric supercapacitors
- 2023
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Ingår i: Nano Energy. - : ELSEVIER. - 2211-2855 .- 2211-3282. ; 114
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Tidskriftsartikel (refereegranskat)abstract
- Ionic thermoelectric supercapacitors (ITESCs) produce orders of magnitude higher voltages than those of con-ventional thermoelectrics (TEs) based on the thermo-diffusion of electrons/holes and are therefore attractive for converting low-grade heat into electricity. The stretchability and stability of the whole ITESC are important for wearable heat harvesting applications. Recent studies on ITESC have focused on stretchable ionic TE electrolytes with a giant Seebeck coefficient, but there are no reports of fully stretchable ITESCs for wearable heat harvesting devices due to the lack of stretchable electrodes and stretchable ionic TE electrolytes with stability. Herein, we present a fully stretchable ITESC composed of stable high-performance ionic thermoelectric elastomer (ITE) electrolyte and stretchable gold nanowire (AuNW) electrodes. The ITE shows excellent air stability (> 60 d) in comparison to hydrogel-based electrolytes that are susceptible to dehydration in ambient conditions. Further-more, the ITE exhibits an apparent thermopower up to 38.9 mV K-1 and ionic conductivity of 3.76 x 10-1 mS cm-1, which both are maintained up to a tensile strain of 250%. Finally, a fully stretchable ITESC with AuNW electrodes is developed which can harvest energy from thermal gradients during deformations.
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