Advances in Functional Solution Processed Planar 1D Photonic Crystals

Abstract

photonic states (PDOS), [2][3][4] which helps explaining the photoluminescence (PL) changes of materials when embedded in the PhC structure.Traditionally, PhCs have been made carving bulky inorganic dielectrics or sem iconductors. These structures are still a hot topic in photonics for optical fibers, light emitting diodes (LEDs), sensors, photo voltaic devices, lasers, discrete and integrated optical components, lightening, and quantum computing. [6] However, new solution processable photoactive materials (e.g., organic semiconductors, quantum dots, hybrid perovskites, and selfassem bling supramolecular systems) stimulated the development of PhCs grown with organic and colloidal materials by solution and melt processes. [7] Among PhCs, distributed Bragg reflectors (DBRs) are cur rently the most interesting owing to their planar structure which generates a simple optical response that represents a playground to understand deep physical concepts, as described in Sections 2.4 and 4. DBRs are indeed made of alternated thin films of different dielectric materials. This simplicity makes them the only PhCs that can take advantage of large area growths (see Section 3.1). [8] Such fabrication methods are unconceivable with bulky inorganic DBRs and might reduce processing costs and enhance customizability, also on industrial scale, thus adding unprecedented market opportunities. Figure 1 illustrates the evolution and fabrications of solution and melt processed DBRs. The top of the Figure displays three wellknown natural DBRs belonging to animal and plant reigns: the mother of pearl, [9] the Panamanian Tortoise beetle exoskel eton, [10] and the Pollia Condensata skin, [11] whose growth is driven by the thermodynamics of spinodal phase separation. [12] The interest in these natural structures leads to their emulation until the development of solutionbased fabrication methods for flexible synthetic DBRs made of polymers and inorganic nanoparticles (Figure 1). At the base of Figure 1, we also show some applications arose only in the last decades. From left to right: the use of DBRs in functional architecture, in enhance ment of photon absorption for photovoltaic cells and modules, emission control, lasing, and sensing. [7c,13] In this paper we will first briefly review the properties of DBRs and then focus on the reasons that guided the research toward new solutionbased and largearea fabrications, describing current processes used both at the laboratory and largearea scales. We will then review the main applications of these structures comparing the performances of mesoporous inorganic and polymer devices. An overview on the properties and applications of polymer and inorganic planar 1D photonic crystals fabricated from solution is provided here. In the last decades, photonic crystals became technologically relevant for light management, photovoltaics, sensing, and lasing. Such structures are traditionally produced by lithographic and vacuum techniques, but the need to reduce costs and to scale-up the fabrication have lea...

Photonic nanoarchitectonics with stimuli-responsive 2D materials

“…features or for the colourful design of buildings with radiation shielding properties. 8,[11][12][13] Stimuli induced color changes based on 2D material structures Besides making use of the "static" structural color of photonic structures, applications relying on dynamic color changes triggered by external stimuli are heavily investigated. 7,11 The main utilization of dynamic structural color changes is in the field of sensing.…”

“…[1][2][3][4] Over the last three decades, substantial progress has been achieved in creating such structural colors in the laboratory. [5][6][7][8][9][10][11][12][13][14][15] As opposed to the colors of dyes and pigments, which are based on the absorption of light, structural color arises due to diffraction, refraction and reflection of light by submicron scale structures. 1,7,8,10 The various artificial architectures that produce structural colors in the laboratory range from simple thin films to more complex 1D, 2D and 3D periodic assemblies of dielectric materials, termed photonic crystals (PC) Fig.…”

“…16,17 The origin of the displayed structural color of the simplest photonic architectures like thin films and one-dimensional photonic crystals (1D PCs), can be derived from the condition for constructive interference by a combination of the Bragg and Snell laws (see Fig. 1e): 11,15,20…”

“…50 With the recent advances in nanosheet processing protocols and tailoring methods, 43,[51][52][53][54] 2D materials made their way into the field of structural colors. 41,[55][56][57][58][59] Although there are excellent recent reviews on structural colors and their applications, 7,8,[10][11][12] 2D materials appear only as minor points in these reviews as most of the research in this field is still carried out with nanoparticles and polymers despite considerable drawbacks compared to 2D materials.…”

Ultrafast photochromism and bacteriochromism in one dimensional hybrid plasmonic photonic structures

“…Alternatively, one-dimensional photonic crystals can be fabricated by stacking two different types of materials, and these multilayer geometries are usually called Bragg stacks [12][13][14][15][16][17] . Bragg stacks are very versatile from a materials point of view because they can be fabricated either with organic [18][19][20] or inorganic materials [21][22][23][24] , exploiting a wide range of refractive index values. If a material that is employed to fabricate the photonic crystal is a plasmonic, e.g.…”