ACS Appl Mater Interfaces. 2018 Jul 11;10(27):23392-23398. doi: 10.1021/acsami.8b04732. Epub 2018 Jun 29.
Photonic crystals are essentially a periodic ("crystalline") arrangement of dielectric nanoparticles that respond in unison to incident light. They can be used to harvest light in various applications such as photocatalysis, solar cells, and lasing. In this work, we prepared the photonic crystals of dendritic fibrous nanosilica (DFNS) by their self-assembly. Because of the narrow particle size distribution of the as-synthesized DFNS, they readily formed colored photonic crystals. The photonic band gap was found to be tunable by using DFNS of various sizes and fiber densities. Notably, even after having similar particle sizes (but with different fiber densities), they showed different photonic band gaps, indicating that the fiber density plays a role in the band gap of photonic crystals. Such observations have not been reported before. This could have arisen from the difference in their refractive indices because of the difference in their fiber densities and hence the variation in the silica content, leading to a different optical signature.
光子晶体本质上是介电纳米粒子的周期性（“晶体”）排列，它们对入射光做出一致响应。它们可以用于各种应用中收集光，例如光催化、太阳能电池和激光。在这项工作中，我们通过自组装制备了树枝状纤维纳米硅（DFNS）的光子晶体。由于合成的 DFNS 的粒径分布较窄，它们很容易形成有色光子晶体。通过使用不同尺寸和纤维密度的 DFNS，发现光子带隙是可调的。值得注意的是，即使具有相似的粒径（但具有不同的纤维密度），它们也表现出不同的光子带隙，这表明纤维密度在光子晶体的带隙中起作用。以前没有报道过这种情况。这可能是由于它们的折射率不同，因为它们的纤维密度不同，因此二氧化硅含量不同，导致光学特性不同。
