Khanin Vasilii M, Vrubel Ivan I, Polozkov Roman G, Shelykh Ivan A, Venevtsev Ivan D, Meijerink Andries, Wieczorek Herfried, Boerekamp Jack, Spoor Sandra, Rodnyi Piotr A, Ronda Cees
Philips Healthcare , High Tech Campus 4 , 5656 AE Eindhoven , The Netherlands.
Utrecht University , Princetonplein 5 , 3584 CC Utrecht , The Netherlands.
J Phys Chem A. 2019 Mar 7;123(9):1894-1903. doi: 10.1021/acs.jpca.8b11778. Epub 2019 Feb 25.
Afterglow is an important phenomenon in luminescent materials and can be desired (e.g., persistent phosphors) or undesired (e.g., scintillators). Understanding and predicting afterglow is often based on analysis of thermally stimulated luminescence (TSL) glow curves, assuming the presence of one or more discrete trap states. Here we present a new approach for the description of the time-dependent afterglow from TSL glow curves using a model with a distribution of trap depths. The method is based on the deconvolution of the energy dependent density of occupied traps derived from TSL glow curves using Tikhonov regularization. To test the validity of this new approach, the procedure is applied to experimental TSL and afterglow data for LuGdGaAlO:Ce ceramics codoped with 40 ppm of Yb or Eu traps. The experimentally measured afterglow curves are compared with simulations based on models with and without the continuous trap depth distribution. The analysis clearly demonstrates the presence of a distribution of trap depths and shows that the new approach gives a more accurate description of the experimentally observed afterglow. The new method will be especially useful in understanding and reducing undesired afterglow in scintillators.
余辉是发光材料中的一种重要现象，可能是人们所期望的（例如，长余辉磷光体），也可能是不期望出现的（例如，闪烁体）。对余辉的理解和预测通常基于热释光（TSL）发光曲线的分析，并假设存在一个或多个离散的陷阱态。在此，我们提出一种新方法，用于描述来自TSL发光曲线的随时间变化的余辉，该方法使用具有陷阱深度分布的模型。该方法基于使用蒂霍诺夫正则化对从TSL发光曲线导出的占据陷阱的能量相关密度进行反卷积。为了测试这种新方法的有效性，将该程序应用于掺有40 ppm Yb或Eu陷阱的LuGdGaAlO:Ce陶瓷的实验TSL和余辉数据。将实验测量的余辉曲线与基于具有和不具有连续陷阱深度分布的模型的模拟结果进行比较。分析清楚地证明了陷阱深度分布的存在，并表明新方法能更准确地描述实验观察到的余辉。这种新方法在理解和减少闪烁体中不期望的余辉方面将特别有用。
