An Optical Power Limiting and Ultrafast Photophysics Investigation of a Series of Multi-Branched Heavy Atom Substituted Fluorene Molecules oleh Hampus Lundén, Delphine Pitrat, Jean-Christophe Mulatier, Cyrille Monnereau, Iulia Minda, Adrien Liotta, Pavel Chábera, Didrik K. Hopen, Cesar Lopes, Stéphane Parola, Tönu Pullerits, Chantal Andraud, Mikael Lindgren