Romero Manuel, Sánchez-Valencia Juan Ramón, Lozano Gabriel, Míguez Hernán
Institute of Materials Science of Seville, Spanish National Research Council - University of Seville, C. Américo Vespucio 49, 41092, Seville, Spain.
Nanoscale. 2023 Sep 29;15(37):15279-15287. doi: 10.1039/d3nr03348a.
In this work, we theoretically and experimentally study the influence of the optical environment on the radiative decay rate of rare-earth transitions in luminescent nanoparticles forming a thin film. We use electric dipole sources in finite-difference time-domain simulations to analyze the effect of modifying the effective refractive index of transparent layers made of phosphor nanocrystals doped with rare earth cations, and propose a correction to previously reported analytical models for calculating the radiative decay rate. Our predictions are tested against an experimental realization of such luminescent films, in which we manage to vary the effective refractive index in a gradual and controllable manner. Our model accurately accounts for the measurements attained, allows us to discriminate the radiative and non-radiative contributions to the time-resolved photoluminescence, and provides a way to rationally tune the spontaneous decay rate and hence the photoluminescence quantum yield in an ensemble of luminescent nanoparticles.
在这项工作中，我们从理论和实验上研究了光学环境对形成薄膜的发光纳米粒子中稀土跃迁辐射衰减率的影响。我们在时域有限差分模拟中使用电偶极子源，以分析改变掺杂稀土阳离子的磷光体纳米晶体构成的透明层的有效折射率的影响，并对先前报道的用于计算辐射衰减率的解析模型提出一种修正。我们的预测通过此类发光薄膜的实验实现进行了检验，在该实验中我们成功以渐进且可控的方式改变有效折射率。我们的模型准确地解释了所获得的测量结果，使我们能够区分时间分辨光致发光中的辐射和非辐射贡献，并提供了一种合理调节自发衰减率从而调节发光纳米粒子集合体中的光致发光量子产率的方法。
