Photoactive Surface-Grafted Polymer Brushes with Phthalocyanine Bridging Groups as an Advanced Architecture for Light Harvesting

Surface-grafted polymer brushes of novel ladder-like architecture were proposed for inducing ordering of chromophores embedded therein. The brushes with acetylene side groups were obtained by surface-initiated photoiniferter-mediated polymerization. The acetylene moieties reacted then via "click" process with an axially azide-bifunctionalized silicon phthalocyanine bridging the neighboring chains that inherently adopt extended conformations in dense brushes. FTIR, quartz crystal microbalance, atomic force microscopy were used to study formation and structure of the photoactive brushes varying in grafting densities. Importantly, photophysical properties of the chromophores were virtually unaffected upon embedding them into the brushes, as evidenced by UV/Vis absorption and emission spectroscopies. The proposed method due to unique ordering of the chromophores open new opportunities for fabrication of light harvesting systems suitable for e.g. photovoltaic or sensing applications.