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High-temperature stable inverse opal photonic crystals via mullite-sol-gel infiltration of direct photonic crystals

2018; Wiley; Volume: 102; Issue: 2 Linguagem: Inglês

10.1111/jace.16012

1551-2916

Priscila Bueno, Kaline P. Furlan, Dachamir Hotza, Rolf Janßen,

Thermal Radiation and Cooling Technologies

Abstract Three‐dimensionally ordered macroporous materials for photonic or refractory applications have been developed by an innovative approach based on mullite sol‐gel infiltration of direct photonic crystals followed by burn‐out and calcination. Direct photonic crystals were obtained using polystyrene spheres templates either by vertical convective self‐assembly or by drop casting. The samples were then infiltrated by spin coating with mullite sol‐gels prepared with two different compositions (74 wt.% Al 2 O 3 , 26 wt.% SiO 2 and 80 wt.% Al 2 O 3 , 20 wt.% SiO 2 ). The inverse opal photonic crystals prepared with both sol‐gels presented a highly ordered porosity and the high‐alumina composition showed stability up to 1500°C. After inversion of the structure (polymeric template burn‐out), the high‐alumina composition showed roundness of the PS templated pores closer to an ideal sphere (Ø = 0.967) when compared to the low‐alumina composition (Ø = 0.954). Although the inverse opal photonic crystals did not present a photonic bandgap, they showed structural stability at high temperatures, which enable their application as refractory materials.