Phase-transition induced thermochromic behavior of schafarzikites

相变诱导的菱铁矿的热致变色行为

• 批准号: 514924554
• 负责人: Professor Dr. Thorsten Michael Gesing
• 金额: --
• 依托单位: Institut für Anorganische Chemie und Kristallographie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/514924554?language=en
• 关键词: Phase; transition; induced; thermochromic; behavior

A thermochromic material can be used as an excellent optical indicator for a given temperature. In this way, a thermochromic phases can be integrated into structural components, indicating a certain risk due to color changes in case of temperature-driven partial or complete failure of materials. Alternatively, it can function, for instance, in space exploration, depending on the relative position of the sun and thus depending on the temperature, as both heat-reflecting and heat-absorbing material. For this purpose, it is planned to investigate materials that can undergo color changes as soon as the critical temperature is reached. Thermochromism can be realized by materials with reversible displacive phase transitions as found in schafarzikite-type structures, leading to reversible color changes over a critical temperature TC. In addition, irreversible reconstructive phase transitions or transformations lead to permanent color changes. If necessary, these two could be combined. In this respect, it is important to understand the color change mechanism with respect to thermal gradient and/or thermal conductivity. Beside the phase-transition temperature (TC), it would be advantageous if the thermochromic transition could be described with only one physical parameter. As such, we propose a single parameter, which can be derived from a transition function. This transition function is assigned to the thermal expansion behavior of the two involved phases, described by the Debye-Einstein-Anharmonicity (DEA) model across the phase transition. To realize thermochromism across phase transitions we propose mullite-type O8 Schafarzikite phases stabilized by stereochemically active lone electron pairs, and their solid solutions as model systems. The project aims at the following milestones: (I) to experimentally validate and, if necessary, to further development the "thermal expansion across phase transition" (TEAPT) model, (II) to characterize the model system L2(M1-xM'x)O4 (L = Pb2+, M = Pb4+, Sn4+, Pt4+) to better understand the crystal-chemico-physical basis of thermochromism across the phase transitions, (III) to create at least the relevant thermochromic oxide library and categorize the environmental-friendly phases that allow a wide temperature range for thermochromic transitions.

热色材料可以用作给定温度的出色光学指示器。通过这种方式，可以将热色体阶段整合到结构成分中，表明在温度驱动的部分或完全失败的情况下，由于颜色变化而导致一定风险。另外，它可以在太空探索中起作用，具体取决于太阳的相对位置，因此取决于温度，因为热量反射和热量吸收材料。为此，计划调查一旦达到临界温度，可以立即发生颜色变化的材料。热色素可以通过具有可逆的位移相变的材料来实现，如Schafarzikite型结构所示，从而导致临界温度TC的可逆颜色变化。此外，不可逆的重建相变或转换导致永久性颜色变化。如有必要，这两个可以组合。在这方面，重要的是要了解有关热梯度和/或导热率的颜色变化机制。除了相位转换温度（TC）以外，如果只能用一个物理参数来描述热色素过渡，这将是有利的。因此，我们提出了一个可以从过渡函数得出的单个参数。该过渡函数分配给了两个相关阶段的热膨胀行为，该阶段由跨相变的Debye-Einstein-Anharmonicity（DEA）模型描述。为了实现整个相变的热色素化，我们提出了通过立体活动活跃的孤独电子对稳定的mullite型O8 schafarzikite阶段，其实心解决方案作为模型系统。该项目旨在以下里程碑：（i）实验验证，并在必要时进行进一步开发“跨相变的热膨胀”（TEAPT）模型，（ii）表征模型系统L2（M1-XM'X） ）o4（l = pb2+，m = pb4+，sn4+，pt4+），以更好地理解整个相变的热染色体的晶体 - 智囊性基础，（iii）至少创建相关的热化氧化物库并对环境进行环境分类。允许热色彩过渡的较宽温度范围的相。