By courtesy of:
R Schroeder, B Ullrich, W Graupner and U Scherf
J. Phys.: Condens. Matter 13 (2001) L313
and a recent biological imaging application study:
Conjugated Polymer Dots for Multiphoton Fluorescence Imaging
Changfeng Wu, Craig Szymanski, Zachary Cain, and Jason McNeill*
JACS 2007, 129, 12904