Fabrication and photophysical properties of singlet oxygen generating nanoporous membrane

The nanoporous alumina membranes (NAMs) were fabricated by a two-step aluminium anodic oxidation process. The fabricated NAMs have controllable pore diameters (40–80 nm) and unidirectionally ordered pore direction. The surface of the NAM was modified with the organo-silane agent (APTES: (aminopropyl)triethoxysilane) to induce ionic bonding between the NAM and the photosensitizer (TSPP: tetrakis(p-sulfonatophenyl)porphyrin). The morphology and chemical nature of the surface modified NAM were studied by field emission scanning electron microscope (FE-SEM), FT-IR spectra, and thermo gravimetric analysis (TGA). Furthermore, this singlet oxygen generating nanoporous membranes (SGNMs) were investigated, in detail, to understand their photophysical properties and the singlet oxygen generation efficiency which were the essential factors for their applications. Steady-state spectroscopies and nanosecond laser induced time-resolved spectroscopy were applied to get information on all photophysical properties including the lifetime of singlet oxygen which depended on the pore diameter of the SGNM.