Solid-State Oxides and Oxide-Fluorides

固态氧化物和氧化物-氟化物

• 批准号: 1307698
• 负责人: Kenneth Poeppelmeier
• 金额: $ 45万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1307698&HistoricalAwards=false
• 关键词: Solid; State; Oxides; Oxide; Fluorides

TECHNICAL SUMMARYEmerging technologies require high-performance nonlinear optical (NLO) materials that exhibit enhanced optical properties at the microscopic and macroscopic level. The rational design of crystal structures, in particular noncentrosymmetric (NCS) materials, and how to target polar, polar-chiral, and chiral structures, is an ongoing theme in crystal engineering. A new class of potentially high performance NLO inorganic materials, solid-state oxide-fluorides, has been identified with the synthesis of new compounds containing [MOxF6-x]2- units in inorganic, solid-state environments. In the process it has been discovered that i) the use of fluoride ligands with early-transition metals (ETMs) enhances the second-order Jahn-Teller distortion in comparison to pure oxide ETM compounds, ii) the synthesis of NCS materials can be achieved with the use of polar basic-building units (BBUs), iii) design of NCS BBUs can predictably lead to NCS structures, iv) the synthesis of compounds that contain two, separate anionic BBUs is likely to result in an NCS compound, and v) the synthesis of ETM oxide-fluoride compounds can produce energy-storage materials such as high-potential primary batteries. Drawing from these learned principles, a program of discovery-based research on NCS structures based on acentric ETM oxide-fluorides (ETMOFs) is planned. These materials comprise a large and new class of solids with properties associated with piezoelectricity, pyroelectricity, ferroelectricity and second harmonic generation (SHG). The structural-property relationships that give rise to high, low, or null nonlinearities of the NLO material are examined. Finally, the growth of large crystals (on the order of 1 cm3) allows detailed analysis with measurements of the NLO tensor and phase-matchability properties, and other properties of interest such as piezoelectricity. The materials synthesized will have potential use in relaxor ferroelectrics and non-linear optics. These materials will have a high damage threshold and the potential for bulk growth to create large, single crystals suitable for optical use and examination. This work is supported by the Solid State and Materials Chemistry Program.NON TECHNICAL SUMMARYAs recently described in a Nature News Feature, the highly-efficient non-linear optical (NLO) oxide-fluoride material KBe2BO3F4 and other NLO materials are essential to act as wave guides for the modification of the amplitude, phase, and/or frequency of an optical signal. Such materials are used in femtosecond laser spectroscopy and-more recently-to generate UV laser light for nanolithography. Such NLO materials are increasingly needed to upconvert laser light to higher energies by second-harmonic generation (SHG). Current research and engineering activities in the field of NLO materials typically concern synthesis of NLO crystals; however, research is lacking in understanding how to design NLO materials and why materials exhibit a particular NLO response. While exploring the fundamental driving factors that create NLO materials, research will be performed to grow large (on the order of cm3) single crystals with a floating zone image furnace to allow a quantitative understanding of the interaction of light with the NLO material. This project concerns such analyses and progress made towards rational synthesis of solid-state inorganic materials and analysis of their structure-property relationships. These analyses of basic principles of the chemistry by graduate students and postdoctoral associates - who are engaged in local education, teaching, mentoring, and leadership - will facilitate broad understanding of stable solid-state compounds.

技术综述新兴技术需要高性能的非线性光学(NLO)材料，在微观和宏观层面上表现出增强的光学性能。合理设计晶体结构，特别是非中心对称(NCS)材料，以及如何针对极性、极性-手性和手性结构，是晶体工程中正在进行的主题。通过在无机、固态环境中合成含[MoxF6-x]2-单元的新化合物，确定了一类潜在的高性能非线性光学无机材料--固态氧化物-氟化物。在这一过程中，人们发现：i)与早过渡金属(ETM)配合使用时，与纯氧化物ETM化合物相比，氟配体的二阶Jahn-Teller失真增强；ii)NCS材料的合成可以通过使用极性基本单元(BBU)来实现，iii)NCS BBU的设计可以预测到NCS结构，iv)含有两个单独的阴离子BBU的化合物的合成很可能导致NCS化合物，以及v)ETM氧化物-氟化合物的合成可以生产高电位一次电池等储能材料。从这些已学到的原理出发，计划开展一项基于发现的基于偏心ETM氧化物-氟化物(ETMOF)的NCS结构的研究计划。这些材料包括一大类新的固体，具有与压电性、热释电性、铁电性和二次谐波产生(SHG)相关的特性。研究了引起NLO材料的高、低或零非线性的结构-性质关系。最后，通过测量NLO张量和相位匹配性，以及其他感兴趣的特性，如压电性，可以对大晶体(约1厘米~3)的生长进行详细分析。所合成的材料将在弛豫铁电体和非线性光学中有潜在的应用。这些材料将具有较高的损伤阈值，并有可能大量生长，以产生适合光学使用和检查的大单晶。这项工作得到了固态和材料化学计划的支持。正如最近在《自然新闻》的一篇专题文章中所描述的那样，高效的非线性光学(NLO)氧化物氟化物材料KBe2BO3F4和其他NLO材料对于充当光信号的幅度、相位和/或频率的波导器至关重要。这种材料被用于飞秒激光光谱分析，最近还被用来产生用于纳米光刻的紫外线激光。这种非线性光学材料越来越需要通过二次谐波产生(SHG)将激光上转换为更高的能量。目前在非线性光学材料领域的研究和工程活动主要涉及非线性光学晶体的合成，然而，对于如何设计非线性光学材料以及为什么材料表现出特殊的非线性光学响应，目前的研究还缺乏。在探索产生非线性光学材料的基本驱动因素的同时，将进行研究，用浮动区域成像炉生长大(约厘米~3)单晶，以便能够定量地了解光与非线性光学材料的相互作用。本项目涉及在固态无机材料的合理合成及其结构-性能关系分析方面取得的分析和进展。从事当地教育、教学、指导和领导工作的研究生和博士后助理对化学基本原理的这些分析将促进对稳定固体化合物的广泛理解。