Sensitization of lanthanide-based phosphors by transition metals for high-brightness tunable thermometers (SensiTherm)

该项目的主要目的是通过过渡金属离子的敏化来增强镧系光学温度计的光致发光性能。利用过渡金属离子显著提高的吸收截面，镧系离子的发射强度可以显著增强，这将提高温度计提供的信号电平。此外，由于从敏化剂到活化剂的能量传递具有强烈的温度依赖性，因此通过过渡金属离子对镧系元素发射的敏化将为提高共掺杂发光温度计的温度灵敏度开辟一条新的途径。为了实现这一目标，将对微晶颗粒中过渡金属离子对镧系元素的敏化过程进行详细的了解。研究了局部晶体场、声子能量、掺杂剂浓度、激活剂和敏化剂激发态之间的能级差等材料参数对温度依赖敏化过程的影响，可以控制和有意设计高发射强度、对温度变化高灵敏度的发光温度计。为了研究能量转移，将在弗罗茨瓦夫合成微晶样品，并在马格德堡使用分散粒子方法和量子产率测量来研究光谱特性，以明确量化吸收，能量转移和发射过程。宿主、敏化剂和激活剂相关参数将通过系统地探测一系列组合进行研究。将测量吸收截面、能量传递率以及辐射和非辐射去激发率，这也将作为弗罗茨瓦夫开发的理论模型的比较。这些速率还将在掺杂剂浓度（敏化剂和激活剂）、激发功率密度和温度的范围内进行测量，以研究每个参数对敏化过程的影响。拟议的项目汇集了弗罗茨瓦夫在过渡金属和镧系掺杂化合物的合成、结构表征和理论方面的专业知识，以及马格德堡在基于探测温度控制流体流动系统中分散颗粒发光的先进光谱技术方面的专业知识。该项目的实施将为过渡金属和镧系元素之间的能量转移过程提供广泛的表征，既有助于基本的理解，也有助于提供具有增强特性的发光温度计（更合适的激发窗口，更高的发射强度，更高的温度灵敏度），这将极大地促进许多科学领域的进步，其中温度是最重要的属性。

The main objective of this project is to enhance the photoluminescence properties of lanthanide-based optical thermometers via sensitization by transition metal ions. Taking advantage of the significantly higher absorption cross section of transition metal ions, the emission intensity of the lanthanide ions can be significantly enhanced, which will increase the signal levels offered by the thermometers. In addition, because the energy transfer from sensitizer to activator is strongly temperature-dependent, the sensitization of lanthanide emissions through transition metal ions will open a new path to enhance the temperature sensitivity of co-doped luminescent thermometers. To achieve this goal a detailed understanding of the sensitization process of lanthanides by transition metal ions in microcrystalline particles will be developed. The influence of material parameters such as local crystal field, phonon energy, dopant concentration, and energy level difference between excited states of activator and sensitizer on the temperature-dependent sensitization process enables the control and intentional design of luminescent thermometers with high emission intensity and high sensitivity to temperature changes. To investigate the energy transfer, microcrystalline samples will be synthesized in Wroclaw, and the spectroscopic properties will be investigated in Magdeburg using dispersed particle methods and quantum yield measurements to unambiguously quantify the absorption, energy transfer and emission processes. Host, sensitizer and activator dependent parameters will be investigated by systematically probing a range of combinations. The absorption cross section, the energy transfer rate, as well as radiative and non-radiative de-excitation rates will be measured, which will also serve as a comparison for theoretical models developed in Wroclaw. Those rates will also be measured over a range of dopant concentrations (sensitizer and activator), excitation power densities and temperatures to investigate the effect of each parameter on the sensitization process. The proposed project brings together the expertise of Wroclaw in the synthesis, structural characterisation and theory of transition metal and lanthanide doped compounds, with that of Magdeburg in advanced spectroscopic techniques based on probing the luminescence of dispersed particles in temperature-controlled fluid flow systems. Implementation of this project will provide an extensive characterization of energy transfer processes between transition metals and lanthanides, for both fundamental understanding as well as to provide luminescence thermometers with enhanced characteristics (more suitable excitation window, higher emission intensity, higher temperature sensitivity) which will greatly contribute to the progress of many fields of science for which temperature is a property of foremost importance.