2019年5月2日Utrecht University Andries Meijerink教授学术报告

报告摘要：

Lanthanides have transformed the world of lighting in the past 40 years. Presently, almost all artificial light sources rely on emission of light by lanthanide ions. In many luminescent materials, also known as phosphors, one-to-one photon conversion downshifts one high energy photon to one lower energy photon in the desired spectral region. However, recently, there is a significant increase of attention for multi-photon phosphors relying on multi-photon conversion processes, either upconversion or downconversion. Insight in the multi-photon processes is not trivial but is needed to understand the mechanism and improve the efficiency of spectral conversion processes in multi-photon phosphors which is crucial for applications, including solar cells to reduce spectral mismatch losses.

In this presentation a short historical introduction to multi-photon conversion phosphors will be followed by an overview of recent developments of efficient up- and downconversion materials. Next it will be discussed how insight can be obtained in the mechanism and efficiency of up- and downconversion processes. An important aspect involves modelling of energy transfer and ligand quenching. For both up- and downconversion examples will be given on how modelling of luminescence decay curves can provide quantitative insight. A new ligand-quenching model will be presented and applied to understand multi-phonon vibrational quenching in NaYF4:Er,Yb upconversion nanocrystals. Finally a new method will be presented that provides direct proof for downconversion. Correlated emission of photons in photon cutting materials can serve as a fingerprint for the occurrence of downconversion and can even be used to quantify the downconversion efficiency.

报告人简介：

Andries Meijerink教授1963年出生于荷兰，1986年和1990年先后获得荷兰乌得勒支大学（Utrecht University）硕士和博士学位，师从于发光学大师George Blasse教授。1990-1991年，前往美国威士康辛大学从事博士后研究工作，合作导师为John Wright教授。1991年任职荷兰乌得勒支大学，1996年晋升教授。2004年至2007年间担任乌得勒支大学化学院院长。2009年当选荷兰皇家科学院院士。

Andries Meijerink教授是荷兰皇家科学院院士，在稀土发光材料和光谱学领域做出了突出的贡献。目前主要研究领域为镧系元素化合物的真空紫外光谱、量子剪裁效应以及半导体材料量子点的光学性质，迄今为止，先后在包括Science、Physical Review Letter、Advanced Materials、Angewandte Chemie-International Edition、Journal of the American Chemical Society等国际重要学术刊物上，发表相关研究论文280多篇。已获授权和申请10个国际发明专利。