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Abstract Natural polymers, particularly plant‐derived nanocelluloses, self‐organize into hierarchical structures, enabling mechanical robustness, bright iridescence, emission, and polarized light reflection. These biophotonic properties are facilitated by the assembly of individual components during evaporation, such as cellulose nanocrystals (CNCs), which exhibit a left‐handed helical pitch in a chiral nematic state. This work demonstrates how optically active films with pre‐programmed opposite handedness (left or right) can be constructed via shear‐induced twisted printing with clockwise and counter‐clockwise shearing vectors. The resulting large‐area thin films are transparent yet exhibit pre‐determined mirror‐symmetrical optical activity, enabling the distinction of absorbed and emitted circularly polarized light. This processing method allows for sequential printing of thin and ultrathin films with twisted layered organization and on‐demand helicity. The complex light polarization behavior is due to step‐like changes in linear birefringence within each deposited layer and circular birefringence, different from that of conventional CNC films as revealed with Muller matrix analysis. Furthermore, intercalating an achiral organic dye into printed structures induces circularly polarized luminescence while preserving high transmittance and controlled handedness. These results suggest that twisted sequential printing can facilitate the construction of chiroptical metamaterials with tunable circular polarization, absorption, and emission for optical filters, encryption, photonic coatings, and chiral sensors. 

Abstract Here it is shown that Ti₃C₂T_xMXene flakes can be co‐assembled with recombinant silk fibroin in aqueous suspensions with silk fibroin nanolayers uniformly covering individual flakes. These bioencapsulated flakes evolve with time due to the gradual growth of silk bundles having β‐sheet secondary organization with unique nanofibrillar morphologies extending across flake edges and forming long fringes around individual MXene flakes. This spontaneous reorganization of recombinant silk suggests surface template‐initiated formation of intramolecular hydrogen bonding of silk backbones assisted by intermolecular electrostatic and hydrogen bonding with the MXene flake. The formation of dense and hydrophobic β‐sheets results in development of a protective shell that hinders the surface oxidation of Ti₃C₂T_xin colloidal solution in water and significantly extends the storage life of the individual MXene flakes. Moreover, assembly into organized laminated composites with individual bioencapsulated flakes tightly interconnected via biopolymer bundles and hairs produces robust freestanding electrically conductive membranes with enhanced transport properties. 

Abstract Shape‐persistent, conductive ionogels where both mechanical strength and ionic conductivity are enhanced are developed using multiphase materials composed of cellulose nanocrystals and hyperbranched polymeric ionic liquids (PILs) as a mechanically strong supporting network matrix for ionic liquids with an interrupted ion‐conducting pathway. The integration of needlelike nanocrystals and PIL promotes the formation of multiple hydrogen bonding and electrostatic ionic interaction capacitance, resulting in the formation of interconnected networks capable of confining a high amount of ionic liquid (≈95 wt%) without losing its self‐sustained shape. The resulting nanoporous and robust ionogels possess outstanding mechanical strength with a high compressive elastic modulus (≈5.6 MPa), comparable to that of tough, rubbery materials. Surprisingly, these rigid materials preserve the high ionic conductivity of original ionic liquids (≈7.8 mS cm⁻¹), which are distributed within and supported by the nanocrystal network‐like rigid frame. On the one hand, such stable materials possess superior ionic conductivities in comparison to traditional solid electrolytes; on the other hand, the high compression resistance and shape‐persistence allow for easy handling in comparison to traditional fluidic electrolytes. The synergistic enhancement in ion transport and solid‐like mechanical properties afforded by these ionogel materials make them intriguing candidates for sustainable electrodeless energy storage and harvesting matrices. 

Abstract Since their inception, quantum dots have proven to be advantageous for light management applications due to their high brightness and well‐controlled absorption, scattering, and emission properties. As quantum dots become commercially available at large scale, the need for robust, stable, and flexible optical components continues to drive the development of robust and flexible quantum dot composite materials. In this review, after a thorough introduction to quantum dots, discussion delves into methods for fabricating quantum dot loaded composite optical elements such as thin films, microfabricated patterns, and microstructures. The importance of surface chemistry and ligand engineering, host matrixes, wet processing, and unique patterning methodologies is presented by considering photostability, aggregation, and phase separation of quantum dots in corresponding composites. With regard to prospective optical applications of quantum dot materials, emphasis is placed on light emitting and guiding composite materials for lasing applications, specifically whispering gallery mode‐based photonic microsystems. These developments will enable novel flexible, portable, and miniaturized optoelectronic devices such as light‐emitting diodes, flexible pixelated displays, solar cells, large‐area microwaveguides, omnidirectional micromirrors, optical metasurfaces, and directional microlasers. 

Abstract The integration of chiral organization with photonic structures found in many living creatures enables unique chiral photonic structures with a combination of selective light reflection, light propagation, and circular dichroism. Inspired by these natural integrated nanostructures, hierarchical chiroptical systems that combine imprinted surface optical structures with the natural chiral organization of cellulose nanocrystals are fabricated. Different periodic photonic surface structures with rich diffraction phenomena, including various optical gratings and microlenses, are replicated into nanocellulose film surfaces over large areas. The resulting films with embedded optical elements exhibit vivid, controllable structural coloration combined with highly asymmetric broadband circular dichroism and a microfocusing capability not typically found in traditional photonic bioderived materials without compromising their mechanical strength. The strategy of imprinting surface optical structures onto chiral biomaterials facilitates a range of prospective photonic applications, including stereoscopic displays, polarization encoding, chiral polarizers, and colorimetric chiral biosensing. 

Abstract Instability of perovskite quantum dots (QDs) toward humidity remains one of the major obstacles for their long‐term use in optoelectronic devices. Herein, a general amphiphilic star‐like block copolymer nanoreactor strategy for in situ crafting a set of hairy perovskite QDs with precisely tunable size and exceptionally high water and colloidal stabilities is presented. The selective partition of precursors within the compartment occupied by inner hydrophilic blocks of star‐like diblock copolymers imparts in situ formation of robust hairy perovskite QDs permanently ligated by outer hydrophobic blocks via coprecipitation in nonpolar solvent. These size‐ and composition‐tunable perovskite QDs reveal impressive water and colloidal stabilities as the surface of QDs is intimately and permanently ligated by a layer of outer hydrophobic polymer hairs. More intriguingly, the readily alterable length of outer hydrophobic polymers renders the remarkable control over the stability enhancement of hairy perovskite QDs.