WEB Bioinspired ceramic-based photonic materials for high-temperature applicationsWednesday (01.01.2020) 00:00 - 00:30 Part of:
Photonic crystals and glasses occur in nature in many insects and birds as structural coloration or functional reflectors, as in the beetle Lamprocyphus augustus from Brazil. These complex nanostructures are capable of selectively reflecting incident electromagnetic radiation and are, thereby, a source of inspiration for technological applications such as in coatings. The spectral range in which the reflection of radiation occurs is defined by the spatial order and parameters of the 3D structure as well as by the material refractive index, all tailored during the fabrication process. However, whereas in nature the temperatures to which these structures are exposed to are usually way below 100 °C, the synthetic materials have target applications, such as reflective thermal barrier coatings, in which the temperatures exceed 1200 °C. Such extreme temperatures are expected to induce detrimental structural changes, e.g. dimensional distortion, grain growth, and eventually loss of 3D spatial ordering, impairing the materials’ photonic properties.
Hereby, we demonstrate the fabrication of high temperature stable ceramic-based photonic materials by two different approaches: i) combination of self-assembly with further infiltration with oxides via binary and super cycle atomic layer deposition (ALD) processes and ii) a heterocoagulation-based co-deposition self-assembly process. A variety of ceramic photonic crystals and glasses will be presented, and their structural and optical properties when exposed to high temperatures will be depicted, including a detailed characterization by ptychographic x-ray computed tomography. The best performance regarding high-temperature stable photonic glasses and crystals was achieved by a co-deposition process using yttria-stabilized zirconia (YSZ) and ALD infiltration of mullite, respectively. These materials kept their photonic properties up to 1400 °C, a remarkable achievement, exceeding previous reports of similar structures.
As an evolution from common self-assembly process, an example of additive manufacturing combined with colloidal assembly will be presented, showing a proof-of-concept for assembly onto inclined surfaces and large areas, which opens new paths for the fabrication of ceramic-based photonic materials.
The authors gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Projektnummer 192346071 – SFB 986.
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