1. Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
2. Laboratory for Air Pollution and Environmental Technology, Empa, 8600 Dübendorf, Switzerland
3. Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
4. Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany