Materials Chemistry and Nanochemistry Research Group, Center for Inorganic and Polymeric Nanomaterials, Chemistry Department, University of Toronto, 80 St. George Street, Toronto, M5S 3H6, Ontario, Canada.
Small. 2011 Dec 16;7(24):3465-71. doi: 10.1002/smll.201101906. Epub 2011 Oct 19.
To manipulate electrons in semiconductor electronic and optical devices, the usual approach is through materials composition, electronic bandgap, doping, and interface engineering. More advanced strategies for handling electrons in semiconductor devices include composition-controlled heterostructures and gradient structures. By analogy to the manipulation of electrons in semiconductor crystals by electronic bandgaps, photons in photonic crystals can be managed using photonic bandgaps. In this context, the simplest photonic crystal is the Bragg mirror, a periodic dielectric construct whose photonic bandgap is engineered through variations of the optical thickness of its constituent layers. Traditionally the materials comprising these periodic dielectric layers are nonporous, and they have mainly been used in the field of optical and photonic devices. More recently these Bragg mirrors have been made porous by building the layers from nanoparticles with functionality and utility that exploit their internal voids. These structures are emerging in the area of photonic color-coded chemical sensing and controlled chemical release. Herein, a strategy for enhancing the functionality and potential utility of nanoparticle Bragg mirrors by making the constituent dielectric layers aperiodic and porous is described. It is exemplified by prototypical tandem and gradient structures that are fully characterized with regards to their structure, porosity, and optical and photonic properties.
为了在半导体电子和光学器件中操纵电子，通常的方法是通过材料组成、能带隙、掺杂和界面工程。处理半导体器件中电子的更先进策略包括组成控制的异质结构和梯度结构。通过类比半导体晶体中电子能带隙对电子的操纵，可以使用光子带隙来管理光子晶体中的光子。在这种情况下，最简单的光子晶体是布拉格镜，这是一种周期性介电结构，其光子带隙是通过改变其组成层的光学厚度来设计的。传统上，构成这些周期性介电层的材料是无孔的，它们主要用于光学和光子器件领域。最近，通过使用具有利用内部空隙的功能和实用性的纳米粒子来构建这些层，这些布拉格镜已经变得多孔。这些结构正在光子彩色编码化学传感和受控化学释放领域崭露头角。本文描述了一种通过使组成介电层非周期性和多孔来增强纳米粒子布拉格镜的功能和潜在用途的策略。通过对全同的串联和梯度结构进行示例，对其结构、孔隙率以及光学和光子特性进行了全面的描述和分析。
