Periodic and non-periodic nanostructured chromogenic thin films and devices

目前研究方案的主要目标是深入研究过渡金属氧化物(TMO)纳米结构的显色性能，并利用这些知识设计具有增强性能的薄膜智能系统。 生色学是指通过施加各种外力，如电场(电致变色)、热(热致变色)、光(光致变色)等，可以引起可逆的光学性质变化的材料研究领域。在无机材料中，三氧化二钨(WO_3)、二氧化钒(VO_2)、三氧化钼(MoO_3)等TMO具有非常有效的显色(开关)性质，近年来已成为基础和应用研究的热点。基于这些材料的设备的互动性正在让位于它们作为智能系统在各个领域的应用。过去几年，我在蒙克顿大学的实验室(薄膜和光子学研究组)进行的研究充分证明了研究各种纳米结构的TMO的重要性。通过一些创新和先进的方法，实现了上述TMO薄膜的纳米结构。研究发现，这种制备TMO的方法不仅可以获得性能更好的TMO基薄膜器件，而且有可能在其中引入新的性质。 因此，在基础研究方面，拟议工作的一个重要部分将致力于深入了解TMO薄膜的诱导纳米结构与显色性能之间的关系。其目的是了解与纳米结构TMO薄膜的性质及其开关特性相关的基本物理和化学原理。由于a)巨大的晶界影响电子传输，b)光学常数(n，k)和孔隙率的变化影响光在这些材料中的传播，c)由于在颗粒周围产生巨大的内表面而产生的化学行为，这些材料的尺寸减小到纳米级预计将带来许多变化。此外，由于纳米结构TMO薄膜的可逆动态(开关)行为，从其基本研究的角度来看，这些变化是复杂的，甚至更有趣。这些TMO的周期性纳米结构有望产生非常有趣和可调的光子性质。基于我2010年的发色可调谐光子特性专利的进一步深入工作将会展开。 在应用研究方面，我们的目标是利用在这些周期性和非周期性纳米结构TMO薄膜上获得的深入知识来制造性能更好的薄膜可切换智能系统，用于能源管理、显示设备等不同领域。

The principal objective of the current research proposal is to undertake an in-depth study of the chromogenic properties of transition metal oxides (TMO) in their nanostructured form and to use this knowledge to design thin film smart systems with enhanced performance. Chromogenics is the field of study of materials in which a reversible optical property change can be induced by applying various external forces such as an electric field (Electrochromics), heat (Themrochromics), light (Photochromics) and more. Amongst the inorganic materials, the TMOs such as, Tungsten trioxide (WO3), Vanadium dioxide (VO2), Molybdenum trioxide (MoO3) and others, are known to exhibit a very efficient form of chromogenic (switching) properties and have become the object of intense basic and applied research in recent years. The interactive nature of devices based on these materials are making way to their application as smart systems in various fields. Research carried out in my laboratory (Thin Films and Photonics Research Group) at Université de Moncton over the last few years has amply demonstrated the significance of working with the nanostructured form of the various TMOs. The nanostrucuring of the above said TMO thin films has been achieved by using certain innovative and advanced methods. It is found that this approach to TMO fabrication not only leads to better performing TMO based thin film devices but also to the possibility of inducing new properties into them. Hence, an important part of the proposed work on the basic research side will be dedicated to the in-depth understanding of the correlation between the induced nanostructure and the chromogenic properties of the TMO thin films. The aim is to understand the fundamental physics and chemistry related to the properties of the nanostructured TMO thin films and their switching properties. The reduction of the dimensions of these materials to nanometric level is expected to bring about numerous changes due to the a) enormous grain boundaries affecting the electron transport, b) change in the optical constants (n,k) and porosity affecting the light propagation in these materials, c) chemical behaviour due to the enormous internal surface created around the grains and more. Also, these changes are complex and even more interesting from their fundamental study point of view due to the reversible dynamic (switching) behaviour of the nanostructured TMO thin films. The periodic nanostructuring of these TMOs are expected to lead to very interesting and tunable photonic properties. Further in-depth work based on my 2010 patent on chromogenically tunable photonic properties will be undertaken. On the applied research side, the aim is to use this in-depth knowledge gained on these periodically and non-periodically nanostructured TMO thin films to fabricate better performing thin film switchable smart systems for application in various sectors such as energy management, display devices and more.