New Oxychalcogenides for Electronic, Magnetic and Optical Applications

固态化学对现代生活的许多领域都有影响。这样的例子不胜枚举：基本上我们使用的所有汽油都是用固态多孔催化剂处理的；现代便携式设备中的燃料电池和可充电电池依赖于固态化学家生产的材料；金属合金和金属氧化物是所有电子产品的关键部件。今天使用的许多材料都是基于金属氧化物。在这些材料中，通常通过在结构中替换不同的金属离子来控制其电子、光学和磁性能。这影响了金属-氧反键带中的电子数，从而改变了性质；化学成分的微小变化可以极大地改变材料的性质。在这个提议中，我们寻求资金来研究氧硫族化合物的化学性质，同时包含O2-和S2-或Se2-阴离子。我们相信这些材料令人兴奋的原因有几个。首先，它们是一个相对未被充分开发的家族，并且有很大的机会制备具有同时存在两种不同阴离子影响性能的新材料。其次，这类材料中的成键与氧化物中的成键明显不同，较高的共价程度导致了在最高能占电子态中金属和阴离子的结合。这为制备p型透明导体等相和生产具有潜在可开发磁性的材料提供了可能性。第三，可以使用材料中的硫系化合物层来稳定氧化层，其结构安排在纯氧化物材料中是找不到的。这种层的新颖结构表明可以发现和利用新的电子和磁性能。在一个工作链中，我们的目标是开发与[Bi2LnO4][Cu2Se2]相关的材料化学（Ln是一种3+镧系元素）。我们希望制备具有一系列潜在有趣性质的化学取代物和相关材料。第二条链的目标是[Ln2O2Q2][M2O] （M是一种过渡金属）材料，它含有一种不寻常的[M2O]原子层，在结构上与许多重要材料中的原子层相关，但其M和O位置相反。我们希望探索可以制备的这种材料的范围，并研究它们的结构、磁性和电子特性。工作的最后一部分将利用我们在已知氧硫属化合物中发现的各种特征的知识来瞄准新的结构类型。总之，这个项目将使我们能够制备令人兴奋的新材料，并研究它们的结构、电子、光学和磁性。

Solid state chemistry has impact on many areas of modern life. Examples are numerous: essentially all the petrol we use has been processed using solid state porous catalysts; the fuel cells and rechargeable batteries in modern portable devices rely on materials produced by solid state chemists; metal alloys and metal oxides form key components of all electronic goods. Many of the materials in use today are based on metal oxides. In these materials electronic, optical and magnetic properties are usually controlled by substituting different metal ions in the structure. This influences the electron count in metal-oxygen antibonding bands which in turn changes properties; seemingly minor changes in chemical composition can dramatically change a material's properties. In this proposal we seek funding to investigate the chemistry of oxychalcogenides, phases which simultaneously contain O2- and S2- or Se2- anions. We believe that these materials are exciting for several reasons. Firstly, they are a relatively under-explored family and there are significant opportunities to prepare new materials with properties influenced by the simultaneous presence of two different anions. Secondly, the bonding in such materials is significantly different to that in oxides and the higher degree of covalency leads to a combination of metal and anion character in the highest energy occupied electronic states. This offers the possibility of preparing phases such as p-type transparent conductors and to produce materials with potentially exploitable magnetic properties. Thirdly, it's possible to use the chalcogenide layers in materials to stabilise oxide layers with structural arrangements that aren't found in pure oxide materials. The novel structures of such layers suggest novel electronic and magnetic properties may be discovered and exploited.In one work strand we aim to develop the chemistry of materials related to [Bi2LnO4][Cu2Se2] (Ln is a 3+ lanthanoid element). There are a wide range of chemical substitutions and related materials we hope to prepare with a range of potentially interesting properties. A second strand targets [Ln2O2Q2][M2O] (M is a transition metal) materials which contain an unusual [M2O] layer of atoms which is structurally related to layers found in many important materials but has M and O positions reversed. We wish to explore the range of such materials that can be prepared and investigate their structural, magnetic and electronic properties. A final strand of the work will use our knowledge of the kinds of features found in known oxychalcogenides to target new structure types.In summary, this project will allow us to prepare exciting new materials and investigate their structural, electronic, optical and magnetic properties.