Frequency-domain method for characterization of upconversion luminescence kinetics

<strong>This folder contains all raw data underlying the results presented in a manuscript, submitted to </strong><strong><em>The Journal of Physical Chemistry Letters</em></strong><strong>, and entitled:</strong> <strong>Frequency-domain method </strong><strong>for </strong><strong>characterization of upconversion luminescence kinetics</strong> <strong>Authored by:</strong> Lucía Labrador-Páez,^a Jouko Kankare,^b Iko Hyppänen,^b Tero Soukka,^b,* Elina Andresen,^c Ute Resch-Genger,^c Jerker Widengren,^a Haichun Liu^a,* <em>^a</em><em>Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden. </em> <em>^b</em><em>University of Turku, Turku, Finland.</em> <em>^c</em> <em>Federal Institute for Materials Research and Testing (BAM), Berlin, Germany. </em> *Corresponding authors: <em>[e-mail]</em><em>; [e-mail].</em> <strong>The data files are grouped according to the different figures in the manuscript where the extracted results are presented.</strong> <strong>ABSTRACT</strong> The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores. This method has its own strengths compared to the TD approach, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with a linear emission, the FD method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated luminescence kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analysed the response of the upconversion luminescence (UCL) of UCNPs in the FD method in theory. We found that the application of this method can potentially obtain the effective decay rates of three critical energy states of the sensitizer and activator ions involved in the upconversion process, from a single experiment. The validity of the FD method is further demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods.本文件夹包含投稿至《物理化学快报》（The Journal of Physical Chemistry Letters）的一篇手稿中所有结果对应的原始实验数据，该手稿标题为《用于上转换发光动力学表征的频域方法》。作者依次为：Lucía Labrador-Páez^a、Jouko Kankare^b、Iko Hyppänen^b、Tero Soukka^b,*、Elina Andresen^c、Ute Resch-Genger^c、Jerker Widengren^a、Haichun Liu^a,*。 ^a 瑞典皇家理工学院应用物理系，斯德哥尔摩，瑞典。 ^b 芬兰图尔库大学，图尔库，芬兰。 ^c 德国联邦材料研究与测试研究所（BAM），柏林，德国。 *通讯作者：[e-mail]；[e-mail]。 数据文件按照手稿中展示对应实验结果的各幅图表进行分组。 **摘要** 频域（frequency-domain, FD）方法为表征发光体的发光动力学提供了一种区别于常用时域（time-domain, TD）方法的备选方案。相较于时域方法，该方法具备独特优势，例如可更可靠且精准地分离多寿命组分。尽管频域方法已被广泛应用于线性发射发光体的表征，但针对稀土掺杂上转换纳米颗粒（lanthanide-doped upconversion nanoparticles, UCNPs）这类具有更复杂发光动力学的非线性发光材料的相关研究仍较为匮乏。本研究采用表征标准双光子能量转移上转换过程的简化速率方程模型，从理论层面系统分析了上转换发光（upconversion luminescence, UCL）在频域方法下的响应特性。研究发现，仅通过单次实验即可获取上转换过程中敏化剂与激活剂离子的三个关键能级的有效衰变率。随后通过实验数据进一步验证了频域方法的有效性，其结果与时域方法得到的结论具有良好的一致性。