The innovation engine for new materials

Linus Haglund


Chalmers University of Technology


Materials Engineering


Clayton Cozzan

Faculty Sponsor(s): 

Ram Seshadri

Faculty Sponsor's Department: 


Project Title: 

New experimental equipment for phosphor-converted solid state white lighting research

Project Description: 

Scientific and public interest in phosphor converted light emitting-diode (pc-LED) devices has soared in the last two decades, mainly owing to their superior energy efficiency and durability compared to conventional light sources. One common approach to produce pc-LED white light is to use a blue LED to excite a yellow-emitting inorganic phosphor, often comprised of cerium-doped yttrium aluminum garnet (Y3Al5O12), or Ce:YAG. The emission color of the phosphor depends on the relationship between the crystal structure and the dopant ion used. To obtain the coveted optical properties, the preparation of phosphors traditionally requires several hours of heating at temperatures above 1500 °C in a reducing atmosphere. However, recent studies have shown that the same material qualities can be obtained by using a conventional microwave oven, using a fraction of the time and energy. Currently, the atmospheric conditions of the heating procedure are not reliably regulated and thus not reproducible. The first goal of the work is to design, build, and test a more controlled setup for the microwave preparation of phosphors. The functionality and reproducibility of a custom made enclosure with nitrogen gas control is currently being tested and optimized. Once phosphor samples are successfully prepared, their structure and properties will be analyzed using powder X-ray diffraction and fluorimetry. Additionally, data on many canonical and novel phosphors are currently being collected for the development of an engineering database, where a user can easily search for phosphors with the desired properties, such as emitted color, absorption wavelength, and efficiency.