Photonic Ink Research Articles

Multifunctional chiral nematic cellulose nanocrystals/glycerol structural colored nanocomposites for intelligent responsive films, photonic inks and iridescent coatings

Structural colored nanocomposites with photonic liquid crystal structures are desirable owing to their excellent optical performances, unique structural features and intelligent responsive behaviors.

Printable UV personal dosimeter: sensitivity as a function of DoD parameters and number of layers of a functional photonic ink

This work presents ‘intelligent papers’ obtained by functional inks printed on cellulose-sheets by DoD inkjet technology and their performance as a photonic device for UV-radiation dosimetry. The dosimeter operation is based on the photodegradation of the active part of a photonic ink, btfa (4,4,4-trifluoro-1-phenyl-1,3-butanedione) ligands in Eu(III) complex, as a function of the UV dose (Jcm−2), and the one-way device is read by the luminescence quenching of (5D0 → 7F2) Eu3+ transition after UV exposure of the printed paper. The printed dosimeter presented an exponential behavior, measured here up to 10 Jcm−2 for UV-A, UV-B and UV-C, and it was shown that the number of jetted layers could fit the dosimeter sensitivity.

A colloidoscope of colloid-based porous materials and their uses.

Nature evolved a variety of hierarchical structures that produce sophisticated functions. Inspired by these natural materials, colloidal self-assembly provides a convenient way to produce structures from simple building blocks with a variety of complex functions beyond those found in nature. In particular, colloid-based porous materials (CBPM) can be made from a wide variety of materials. The internal structure of CBPM also has several key attributes, namely porosity on a sub-micrometer length scale, interconnectivity of these pores, and a controllable degree of order. The combination of structure and composition allow CBPM to attain properties important for modern applications such as photonic inks, colorimetric sensors, self-cleaning surfaces, water purification systems, or batteries. This review summarizes recent developments in the field of CBPM, including principles for their design, fabrication, and applications, with a particular focus on structural features and materials' properties that enable these applications. We begin with a short introduction to the wide variety of patterns that can be generated by colloidal self-assembly and templating processes. We then discuss different applications of such structures, focusing on optics, wetting, sensing, catalysis, and electrodes. Different fields of applications require different properties, yet the modularity of the assembly process of CBPM provides a high degree of tunability and tailorability in composition and structure. We examine the significance of properties such as structure, composition, and degree of order on the materials' functions and use, as well as trends in and future directions for the development of CBPM.

Glassy photonic inks encapsulated in core–shell microcapsules for local electric field sensors

Photonic inks encapsulated in eccentric core–shell microcapsules form glassy photonic structures under an electric field by dielectrophoretic assembly. The property of the photonic inks exhibiting various photonic colors depending on the strength of local electric field has been utilized for measuring the electric field gradients by reading hue distances.

Robust microfluidic encapsulation of cholesteric liquid crystals toward photonic ink capsules.

Robust photonic microcapsules are created by microfluidic encapsulation of cholesteric liquid crystals with a hydrogel membrane. The membrane encloses the cholesteric core without leakage in water and the core exhibits pronounced structural colors. The photonic ink capsules, which have a precisely controlled bandgap position and size, provide new opportunities in colorimetric micro-thermometers and optoelectric applications.

Surface-Initiated Polymerization as an Enabling Tool for Multifunctional (Nano-)Engineered Hybrid Materials

Surface-initiated atom transfer radical polymerization (SI-ATRP) has become an indispensable tool for engineering the structure and properties of polymer/inorganic and polymer/organic interfaces. This article describes the progress and challenges that are associated with the application of SI-ATRP to precisely control the molecular characteristics of polymer chains tethered to nanoparticle surfaces and explores the properties and potential applications of the resulting particle brush materials. Even for the conceptually most “simple” particle brush systems—that is, spherical particles uniformly grafted with amorphous nonpolar polymers—the complex superposition of interactions as well as time- and length-scales related to particle core and tethered chains provides a rich and largely unexplored parameter space for the design of novel functional materials. The application of the particle brush approach to the development of materials for applications ranging from photonic inks and paints to advanced high “k” dielectrics for energy storage and advanced nanocomposite materials with improved optical, mechanical, or transport characteristics is discussed.

Magnetically rewritable photonic ink based on superparamagnetic nanochains

One-dimensional photonic nanochains composed of periodically arranged superparamagnetic nanoparticles have been exploited as basic color units for a new type of photonic ink. The photonic response of ink can be rapidly and repetitively switched on and off by tuning the direction of external magnetic fields. Temporary bi-stability is realized in the photonic ink by introducing highly viscous solvents as a dispersant, which suppress the rotational movement of nanochains and allow them to stay temporarily aligned after the removal of external magnetic field and to retain their photonic response for a considerably long period. Increasing the viscosity of the dispersant enhances the bi-stability of photonic inks; for instance, the ink prepared in 95% glycerol solution is able to retain its color up to ten minutes. The length of the chains also plays an important role in their temporary bi-stability. By mixing chains with different photonic properties and lengths, a display has been developed which exhibits two distinct colors in response to the application and removal of external magnetic fields.

5.2: Photonic Crystal Display Materials

AbstractOpalux Incorporated has developed a technology called Photonic Ink P‐Ink. P‐Ink comprises an active photonic crystal which reflects a band of color that can be tuned by controlling the applied current or voltage. All the individual spectral colors in the visible range can be reflected by a single P‐Ink material. This provides an opportunity to create a wider range of primary colors than the conventional RGB system given the same numbers of pixels for color mixing. Other performance characteristics of P‐Ink technology such as high reflectivity, fast switching speed, and low power consumption also suggest a promising candidate for next‐generation full color reflective display applications.

Photonic Crystal Display Materials

Photonic Ink (P-Ink) technology comprises an active photonic crystal that reflects a band of color that can be tuned by controlling the applied current or voltage. All the individual spectral colors in the visible range can be reflected by a single P-Ink material. This technology provides an opportunity to create a wider range of primary colors than the conventional RGB system, given the same numbers of pixels for color mixing.

Development of photonic crystal composites for display applications

Abstract— With an ever‐increasing demand for bigger, brighter, and more‐efficient displays, the research into new display technologies is consistently vibrant and groundbreaking. In this paper, a new type of display material based on the electrical actuation of photonic crystals is described. This material, called Photonic Ink, is capable of reflecting bright and narrow bands of color tunable throughout the entire visible spectrum as well as into the UV or NIR. P‐Ink devices are switched at low voltage and display electrical bistability, leading to very low power consumption. The characteristics of the P‐Ink material make it a viable option for color‐based reflective‐display devices.

Self-Assembly of “Paint-On” Colloidal Crystals Using Poly(styrene-co-N-isopropylacrylamide) Spheres

We report on the synthesis of monodispersed, spherical colloidal particles composed of poly(styrene-co-N-isopropylacrylamide) (pS-co-NIPAm) that rapidly self-assemble via simple solvent evaporation to form 3-D colloidal crystals that are both robust and uniformly diffractive. As a suspension of the pS-co-NIPAm particles dries, the interactions of their soft, flexible peripheries assist in particle self-assembly to form a close-packed ordered structure. Interparticle adhesion occurs at these contacts as the final amount of solvent evaporates, enhancing the durability of the assembly. The dense core provides stability of the ordered structure subsequent to drying. These dried, crystalline films exhibit Bragg diffraction, which can be modified by changing the particle size through varying the monomer feed concentrations. The facile drying process used for crystalline assembly presents a unique approach to photonic inks that can be used as “paint-on” (i.e., processable) dispersions, which are advantageous for the fabrication of materials for optical applications.

Towards photonic ink (P‐ink): a polychrome, fast response metallopolymer gel photonic crystal device

AbstractWe demonstrate here a new kind of planarized and oriented colloidal photonic crystal device whose optical stop‐band position, width and intensity can be reversibly redox and solvent tuned over a broad wavelength range by an anisotropic expansion of the photonic lattice. The material is composed of silica microspheres in a matrix of crosslinked polyferrocenylsilane[1], a metallopolymer network with a continuously variable state of oxidation[2]. Optical data was fitted using a scalar wave approximation, with a congruence to experimental data, allowing facile extraction of information concerning polymer swelling behaviour. The chemomechanical polychrome optical response of the material was exceptionally fast, attaining its fully swollen state from the dry shrunken state on a sub‐second time‐scale.

A Polychromic, Fast Response Metallopolymer Gel Photonic Crystal with Solvent and Redox Tunability: A Step Towards Photonic Ink (P‐Ink)

A broadly wavelength tunable polyferrocenylsilane–silica composite photonic crystal with a fast response is presented. Polychromic variation in the reflection wavelength is effected via the swelling by solvent of a crosslinked redox‐active metallopolymer gel network incorporated in the voids of a planarized silica colloidal crystal film. The Figure demonstrates the fast mechanical response of the composite photonic crystals.