Light or Darkness: Luminescence and quenching of phosphors for LEDs and sensing

For luminescent materials competition between radiative decay (emission of photons, light) and non-radiative decay (conversion of excited state energy to heat) is crucial for their performance. This battle between light and darkness is the topic in this thesis for a selection of materials that (may) find application in displays, lighting and optical sensing. New insights are presented for different types of materials (insulator or semiconductor, doped or undoped), activator ions (transition metal or lanthanide) and size (micro- or nanocrystalline) and contribute to a brighter future.